chemmacros (12sep15)

git-svn-id: svn://tug.org/texlive/trunk@38359 c570f23f-e606-0410-a88d-b1316a301751

29 files changed, 11294 insertions, 5489 deletions

diff --git a/Master/texmf-dist/doc/latex/chemmacros/README b/Master/texmf-dist/doc/latex/chemmacros/README
index ecd8835def6..d7bbd234cc6 100644
--- a/Master/texmf-dist/doc/latex/chemmacros/README
+++ b/Master/texmf-dist/doc/latex/chemmacros/README
@@ -1,11 +1,12 @@
 --------------------------------------------------------------------------
-the CHEMMACROS package v4.7 2015/02/08
+the CHEMMACROS package v5.0 2015/09/11
 
-  macros and commands for chemists
+  comprehensive support for typesetting chemistry documents
 
 --------------------------------------------------------------------------
 Clemens Niederberger
 Web:    https://github.com/cgnieder/chemmacros/
+        http://www.mychemistry.eu/forums/forum/2430/
 E-Mail: contact@mychemistry.eu
 --------------------------------------------------------------------------
 Copyright 2011-2015 Clemens Niederberger
@@ -23,8 +24,10 @@ This work has the LPPL maintenance status `maintained'.
 The Current Maintainer of this work is Clemens Niederberger.
 --------------------------------------------------------------------------
 The chemmacros package consists of the following files
- - chemmacros.sty,
+ - chemmacros.sty, chemmacros4.sty, chemmacros5.sty,
  - chemmacros_en.tex, chemmacros_en.pdf,
+ - quite a number of module files following the naming scheme
+   chemmacros.module.*.code.tex
  - README
 --------------------------------------------------------------------------
 If you have any ideas, questions, suggestions or bugs to report, please
diff --git a/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.pdf b/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.pdf
index 603eafab494..9affd83f227 100644
--- a/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.pdf
+++ b/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.pdf
diff --git a/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.tex b/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.tex
index 511935388ea..26d3d45e756 100644
--- a/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.tex
+++ b/Master/texmf-dist/doc/latex/chemmacros/chemmacros_en.tex
@@ -1,22 +1,23 @@
-% !arara: pdflatex
+% arara: pdflatex
 % !arara: biber
 % arara: pdflatex
 % arara: pdflatex
 % --------------------------------------------------------------------------
 % the CHEMMACROS package
 %
-%   macros and commands for chemists
+%   comprehensive support for typesetting chemistry documents
 %
 % --------------------------------------------------------------------------
 % Clemens Niederberger
 % --------------------------------------------------------------------------
 % https://github.com/cgnieder/chemmacros/
+% http://www.mychemistry.eu/forums/forum/chemmacros/
 % contact@mychemistry.eu
 % --------------------------------------------------------------------------
 % If you have any ideas, questions, suggestions or bugs to report, please
 % feel free to contact me.
 % --------------------------------------------------------------------------
-% Copyright 2011-2015 Clemens Niederberger
+% Copyright 2015 Clemens Niederberger
 %
 % This work may be distributed and/or modified under the
 % conditions of the LaTeX Project Public License, either version 1.3
@@ -32,11 +33,11 @@
 % --------------------------------------------------------------------------
 \documentclass[load-preamble+]{cnltx-doc}
 \usepackage[utf8]{inputenc}
-\usepackage[greek=newtx]{chemmacros}
+\usepackage{chemmacros}
 \setcnltx{
   package  = {chemmacros},
-  info     = {macros and commands for chemists},
-  url      = https://github.com/cgnieder/chemmacros/ ,
+  info     = {comprehensive support for typesetting chemistry documents},
+  url      = http://www.mychemistry.eu/forums/forum/chemmacros/ ,
   authors  = Clemens Niederberger ,
   email    = contact@mychemistry.eu ,
   abstract = {%
@@ -44,72 +45,95 @@
     \includegraphics{chemmacros-logo.pdf}
     \par
   } ,
+  quote-format = \small\biolinumLF ,
   add-cmds = {
      abinitio, activatechemgreekmapping, AddRxnDesc, anti, aq, aqi,
      ba, bond, bridge,
     cd, ch, changechemgreeksymbol, charrow, chcpd, chemabove, chemalpha,
       chembeta, chemgamma, chemdelta, chemDelta, chemformula@bondlength,
+      ChemModule,
       chemomega, chemphi, chemPhi, chemsetup, chlewis, chname , cip, cis, ch,
       CNMR,
     data, DeclareChemArrow, DeclareChemBond, DeclareChemBondAlias,
-      declarechemgreekmapping, DeclareChemIUPAC, DeclareChemLatin,
-      DeclareChemNMR, DeclareChemParticle, DeclareChemPhase,
-      DeclareChemReaction, DeclareChemState, delm, delp, Delta, Dfi,
-    el, ElPot, endo, Enthalpy, enthalpy, Entropy,
-    fmch, fpch, fscrm, fscrp,
-    gas, ghs, ghslistall, ghspic, Gibbs, gram,
+      declarechemgreekmapping, DeclareChemCharge, DeclareChemIUPAC,
+      DeclareChemIUPACShorthand, DeclareChemLatin, DeclareChemNMR,
+      DeclareChemNucleophile, DeclareChemPartialCharge, DeclareChemParticle,
+      DeclareChemPhase, DeclareChemReaction, DeclareChemState,
+      delm, delp, Delta, Dfi,
+    el, ElPot, endo, Enthalpy, enthalpy, entropy,
+    fdelm, fdelp, fmch, fminus, fpch, fplus, fscrm, fscrp,
+    gas, ghs, ghslistall, ghspic, gibbs, gram,
     hapto, HNMR, Helmholtz, hydrogen,
-    insitu, invacuo, iupac,
+    IfChemCompatibilityF, IfChemCompatibilityT, IfChemCompatibilityTF, insitu,
+      invacuo, isotope, iupac,
     Ka, Kb, Kw,
     Lfi, listofreactions, lqd,
     mch, mega, meta, mhName,
     NewChemArrow, NewChemBond, NewChemBondAlias,
-      newchemgreekmapping, NewChemIUPAC, NewChemLatin,
-      NewChemNMR, NewChemParticle, NewChemPhase,
-      NewChemReaction, NewChemState,
+      newchemgreekmapping, NewChemCharge, NewChemIUPAC, NewChemIUPACShorthand,
+      NewChemLatin, NewChemNMR, NewChemNucleophile, NewChemPartialCharge,
+      NewChemParticle, NewChemPhase, NewChemReaction, NewChemState,
       newman, nitrogen, NMR, Nu, Nuc,
     orbital, ortho, ox, OX, oxygen,
     para, pch, per, pH, phase, phosphorus, photon, pKa, pKb, pOH, pos,
-      positron, Pot, prt,
-    Rad, redox, RenewChemArrow, RenewChemBond, renewchemgreekmapping,
-      RenewChemIUPAC, RenewChemLatin, RenewChemNMR, RenewChemParticle,
+      positron, Pot, ProvideChemArrow, ProvideChemBond, ProvideChemCharge,
+      ProvideChemIUPAC, ProvideChemIUPACShorthand, ProvideChemLatin,
+      ProvideChemNMR, ProvideChemNucleophile, ProvideChemPartialCharge,
+      ProvideChemParticle, ProvideChemPhase, ProvideChemReaction,
+      ProvideChemState, prt,
+    Rad, redox, RemoveChemIUPACShorthand, RenewChemArrow, RenewChemBond,
+      renewchemgreekmapping, renewChemCharge, RenewChemIUPAC,
+      RenewChemIUPACShorthand, RenewChemLatin, RenewChemNMR,
+      RenewChemNucleophile, RenewChemPartialCharge, RenewChemParticle,
       RenewChemPhase, RenewChemState,
     Sf, scrm, scrp, second, selectchemgreekmapping, setchemformula,
-      ShowChemArrow, ShowChemBond, sld, Sod, State, sulfur,
+      ShowChemArrow, ShowChemBond, sld, Sod, state, sulfur,
     trans,
+    usechemmodule,
     val
   } ,
   add-silent-cmds = {
     addplot,
     bottomrule,
     cancel, cdot, ce, cee, celsius, centering, chemfig, chemname, clap,
-      cnsetup, color, cstack, cstsetup,
+      cnsetup, code, color, cstack, cstsetup,
     DeclareInstance, DeclareSIUnit, definecolor, draw,
-    electronvolt,
+    electronvolt, endtikzpicture,
     footnotesize,
     glqq, grqq,
     hertz, hspace,
     includegraphics, intertext, IUPAC,
     joule,
-    kilo,
-    latin, lewis, Lewis, liquid, ltn,
+    kelvin, kilo,
+    latin, lc, lewis, Lewis, liquid, ltn,
     metre, midrule, milli, mmHg, mole,
     nano, nicefrac, num, numrange,
     ominus, oplus,
     percent, pgfarrowsdeclarealias, pgfarrowsrenewalias,
     renewtagform, rightarrow,
-    sample, scriptscriptstyle, setatomsep, setbondoffset, sfrac, shorthandoff,
-      si, SI, sisetup, square, subsection,
-    textcolor, textendash, textsuperscript, tiny, toprule,
+    sample, scriptscriptstyle, setatomsep, setbondoffset, sfrac, shade,
+      shadedraw, shorthandoff, si, SI, sisetup, square, subsection,
+    textcolor, textendash, textsuperscript, tikz, tikzpicture, tiny, toprule,
     upbeta, upeta, upgamma, usetikzlibrary,
     volt, vphantom, vspave,
     xspace,
     z@, z@skip
-  }
+  } ,
+  index-setup = { othercode = \footnotesize , level = \section } ,
+  makeindex-setup = { columns = 2 , columnsep = 1em }
 }
 
 \usepackage{chemfig,booktabs,cancel,varioref,csquotes}
 
+\usepackage[
+  a4paper,
+  top    = .1\paperheight,
+  bottom = .1\paperheight,
+  left   = .2\paperwidth,
+  right  = .1\paperwidth
+]{geometry}
+
+
 \expandafter\def\csname libertine@figurestyle\endcsname{LF}
 \usepackage[libertine]{newtxmath}
 \expandafter\def\csname libertine@figurestyle\endcsname{OsF}
@@ -168,9 +192,13 @@
 }
 
 \chemsetup{
-  option/synchronize ,
-  chemformula/format = \libertineLF
+  modules = all ,
+  greek = newtx ,
+%  chemformula/format = \libertineLF
 }
+\setchemformula{format = \libertineLF}
+
+\usepackage{siunitx}
 
 \sisetup{
   detect-mode=false,
@@ -180,7 +208,7 @@
 
 \usepackage{filecontents}
 
-\defbibheading{bibliography}{\addsec{References}}
+\defbibheading{bibliography}{\section{References}}
 \addbibresource{\jobname.bib}
 \begin{filecontents*}{\jobname.bib}
 @book{iupac:greenbook,
@@ -190,6 +218,7 @@
     Michio Takami and Anders J Thor} ,
   title     = {``Quantities, Symbols and Units in Physical Chemistry'', \acs{iupac}
     Green Book} ,
+  shorttitle = {The \acs{iupac} Green Book} ,
   sorttitle = {Quantities, Symbols and Units in Physical Chemistry} ,
   indexsorttitle = {Quantities, Symbols and Units in Physical Chemistry} ,
   edition   = {3rd Edition. 2nd Printing} ,
@@ -200,6 +229,7 @@
   author    = {Neil G. Connelly and Ture Damhus and Richard M. Hartshorn and
     Alan T. Hutton} ,
   title     = {``Nomenclature of Inorganic Chemistry'', \acs{iupac} Red Book} ,
+  shorttitle = {The \acs{iupac} Red Book} ,
   sorttitle = {Nomenclature of Inorganic Chemistry} ,
   indexsorttitle = {Nomenclature of Inorganic Chemistry} ,
   year      = {2005} ,
@@ -210,6 +240,7 @@
   author    = {R. Panico and W. H. Powell and J-C. Richer},
   title     = {``Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F,
     and H'', \acs{iupac} Blue Book},
+  shorttitle = {The \acs{iupac} Blue Book} ,
   sorttitle = {Nomenclature of Organic Chemistry} ,
   indexsorttitle = {Nomenclature of Organic Chemistry} ,
   edition   = {\mkbibacro{draft}},
@@ -237,6 +268,27 @@
   urldate  = {2012-03-20} ,
   date     = {2012-03-20}
 }
+@online{mychemistry:chemmacros-dev,
+  author  = {Clemens Niederberger} ,
+  title   = {chemmacros development} ,
+  url     = {http://www.mychemistry.eu/2015/06/chemmacros-development/} ,
+  urldate = {2015-07-16} ,
+  date    = {2015-06-14}
+}
+@online{mychemistry:modular-chemmacros,
+  author  = {Clemens Niederberger} ,
+  title   = {modular chemmacros} ,
+  url     = {http://www.mychemistry.eu/2015/06/modular-chemmacros/} ,
+  urldate = {2015-07-16} ,
+  date    = {2015-06-08}
+}
+@online{mychemistry:chemmacros-update-how,
+  author  = {Clemens Niederberger} ,
+  title   = {a new chemmacros -- but how?} ,
+  url     = {http://www.mychemistry.eu/2015/07/a-new-chemmacros-but-how/} ,
+  urldate = {2015-07-16} ,
+  date    = {2015-07-15}
+}  
 \end{filecontents*}
 
 \DeclareInstance{xfrac}{chemformula-text-frac}{text}
@@ -253,6 +305,7 @@
 \usetikzlibrary{calc,positioning,decorations.pathmorphing,patterns}
 
 % \newpackagename\chemmacros{chemmacros}
+\newcommand*\chemmacrosversion{\csname c_chemmacros_version_number_tl\endcsname}
 \newpackagename\chemformula{chemformula}
 \newpackagename\ghsystem{ghsystem}
 \newpackagename\chemgreek{chemgreek}
@@ -261,569 +314,689 @@
 \newcommand*\TikZ{Ti\textit{k}Z}
 \newcommand*\tablehead[1]{\textrm{\bfseries#1}}
 
-\NewChemPhase{\aqi}{aq,$\infty$}% aqueous solution at infinite dilution
-\NewChemPhase{\cd}{cd}% condensed phase
-\NewChemPhase{\lc}{lc}% liquid crystal
+% \NewChemPhase{\aqi}{aq,$\infty$}% aqueous solution at infinite dilution
+% \NewChemPhase{\cd}{cd}% condensed phase
+% \NewChemPhase{\lc}{lc}% liquid crystal
 
 \newname\hensel{Martin Hensel}
 \newname\pedersen{Bj\o rn Pedersen}
 
-\BeforeBeginEnvironment{example}{\vspace{\baselineskip}}
-\AfterEndEnvironment{example}{\vspace{\baselineskip}}
-\BeforeBeginEnvironment{sourcecode}{\vspace{\baselineskip}}
-\AfterEndEnvironment{sourcecode}{\vspace{\baselineskip}}
+% \undef\module
+% \undef\moduleidx
+\newidxcmd\chemmodule{\code{#1}}[ (module)]
+\AtEndPreamble{%
+  \pdfstringdefDisableCommands{%
+    \def\chemmodule*#1{\textquotedblleft#1\textquotedblright}%
+  }%
+}
+\newidxcmd\sym{\code{#1}}[ (symbol)]
+
+\makeatletter
+\def\cnltx@bash@listings@style{
+  language         = bash,
+  basicstyle       = {\sourceformat\color{black}},
+  % numbers          = left,
+  % numberstyle      = \tiny,
+  xleftmargin      = 1em,
+  numbersep        = .75em,
+  gobble           = \cnltx@gobble ,
+  columns          = fullflexible,
+  literate         =
+    {ä}{{\"a}}1
+    {ö}{{\"o}}1
+    {ü}{{\"u}}1
+    {Ä}{{\"A}}1
+    {Ö}{{\"O}}1
+    {Ü}{{\"U}}1
+    {ß}{{\ss}}1 ,
+  breaklines       = true,
+  keepspaces       = true,
+  breakindent      = 1em,
+  commentstyle     = \color{comment},
+  keywordstyle     = \color{black}\bfseries ,
+  stringstyle      = \color{black} ,
+  showstringspaces = false ,
+  morekeywords     = texdoc
+}
+
+\cnltx@expandargs(nx)\lstdefinestyle
+  {bash}
+  {\expandonce\cnltx@bash@listings@style}
+
+\newcommand*\prompt{}
+\patchcmd\lst@NewLine
+  {\hbox{}}% search
+  {\hbox{}\prompt}% replace
+  {}% success
+  {}% failure
+\newsourcecodeenv[
+  code-only,
+  sourcecode-options={style=bash},
+  pre-code=\def\prompt{\textasciitilde\space\$\space}
+]{bash}
+\makeatother
+
+\renewcommand*\dictumauthorformat[1]{#1}
+\renewcommand*\raggeddictumtext{}
+
+\newcommand*\TF{\textcolor{red}{\uline{\code{\textcolor{cs}{\textit{TF}}}}}}
+
+\makeatletter
+\renewenvironment{commands}
+  {%
+    \cnltx@set@catcode_{12}%
+    \let\command\cnltx@command
+    \cnltxlist
+  }
+  {\endcnltxlist}
+\newenvironment{tikzcode}
+  {%
+    \def\arrowtip{\@cnltx@option@item\code}%
+    \cnltxlist
+  }
+  {\endcnltxlist}
+
+\newrobustcmd*\showenv[1]{\beginenv*\code{\{}\env{#1}\code{\}}}
+\makeatother
+
+\ExplSyntaxOn
+\cs_new_protected:Npn \chemboldchecks #1
+  {
+    \seq_set_map:NNn \l_tmpa_seq \l__chemmacros_if_bf_seq { \code {##1} }
+    \seq_use:Nnnn \l_tmpa_seq {,~} {,~} {~#1~}
+  }
+\ExplSyntaxOff
 
 \begin{document}
 
 \part{Preliminaries}
-\section{Licence, Requirements and \textsc{README}}
+\section{Licence, Requirements and \textsc{README}}\label{sec:licence-requ-readme}
 \license
 
-The \chemmacros\ package needs the bundles \bnd{l3kernel}~\cite{bnd:l3kernel}
-and \bnd{l3packages}~\cite{bnd:l3packages}.  It also needs the packages
-\needpackage{siunitx}~\cite{pkg:siunitx},
-\needpackage{mathtools}~\cite{pkg:mathtools}, \needpackage{bm}~\cite{pkg:bm},
-\needpackage{nicefrac}~\cite{pkg:nicefrac} and
-\needpackage{environ}~\cite{pkg:environ} as well as
-\pkg{tikz}\footnote{\CTANurl[graphics]{pgf}}~\cite{pkg:pgf} and the \TikZ\
-libraries \code{calc} and \code{arrows}.  Language support is done with the
-help of the \needpackage{translations}~\cite{pkg:translations}.  The
-\chemmacros\ package also loads the packages
-\pkg{chemformula}~\cite{pkg:chemformula} and
-\pkg{chemgreek}~\cite{pkg:chemgreek}.
-
-The package option \option{xspace} also loads the package
-\pkg{xspace}~\cite{pkg:xspace}.
-
-The package option \option{ghsystem} also loads the package
-\pkg{ghsystem}~\cite{pkg:ghsystem}.
-
-
-\section{Motivation and Background}
-\chemmacros\ started some years ago as a growing list of custom macros that I
-frequently used.  I cannot completely recall when and why I decided to release
-them as a package.  Well -- here we go and you might find it useful, too, I
-hope.
-
-Both the macros and their functionality have changed over time and quite a lot
-have been added.  Many things have been unified and what's probably most
-important: many possibilities to customize have been added, too.
-
-Probably every chemist using \LaTeXe\ is aware of the great \pkg{mhchem}
-package by \hensel.  There have always been some difficulties intertwining it
-with \chemmacros, though.  Also, some other minor points in \pkg{mhchem}
-always bothered me, but they hardly seemed enough for a new package.  They
-weren't even enough for a feature request to the \pkg{mhchem} author.  The
-challenge and the fun of creating a new package and the wish for a highly
-customizable alternative led to \chemformula\ after all.  \chemformula{} used
-to part of \chemmacros{} for quite a while but now is an independent package.
-
-As a chemist you are probably aware of the fact that the \acl{UN} have
-developed the \ac{ghs} as a global replacement for the various different
-systems in different countries.  While it has not been implemented by all
-countries yet~\cite{unece:ghsystem_implementation}, it is only a matter of
-time.
-
-The package \ghsystem\ enables you to typeset all the hazard and precautionary
-statements and pictograms in a very easy way.  The statements are taken from
-\acs{eu} regulation 1272/2008~\cite{eu:ghsystem_regulation}.  \ghsystem{} used
-to be a part of \chemmacros{} for quite a while but now is an independent
-package.
-
-There are four points I hope I have achieved with this package:
+\chemmacros\ loads the packages \pkg{expl3}~\cite{bnd:l3kernel} and
+\pkg{xparse}~\cite{bnd:l3packages}.  Depending on your usage other packages
+will be loaded.  They are mentioned when the corresponding module using the
+package is described.
+
+\section{Motivation and Background}\label{sec:motiv-backgr}
+This package grew from a small collection of personal helper macros back
+in~2010 into a rather big package supporting various different chemical
+typesetting tasks.  I hope I have achieved the following points with this
+package:
 \begin{itemize}
-  \item intuitive usage as far as the syntax of the commands is concerned
-  \item the commands shall not only make typesetting easier and faster but also
-    the document source more readable with respect to semantics
+  \item Intuitive usage as far as the syntax of the commands is concerned.
+  \item A comprehensive set of macros! If there are any needs you might have
+    with respect to typesetting of chemistry which is not supported by this
+    package\footnote{Not including needs already solved by other packages such
+      as \pkg{chemnum} or \pkg{chemfig}.} then let me know so \chemmacros\ can
+    be extended.
+  \item The commands shall not only make typesetting easier and faster but
+    also the document source more readable with respect to semantics
     (\code{\cs{ortho}-dichlorobenzene} is easier to read and understand than
-    \code{\cs*{textit}\Marg{o}-dichlorobenzene})
-  \item as much customizability as I could think of so every user can adapt the
-    commands to his or her own wishes
-  \item default settings compliant with the recommendations of the \acf{iupac}.
-\end{itemize}
-Especially the last point needed some pushing from users to get things right
-in many places.  If you find anything not compliant with \ac{iupac}
-recommendations\footnote{This does not concern the \cs{ox} command. The
-  \ac{iupac} version is \cs{ox}\sarg.} I would welcome an email very much!
-
-\section{News}
-\subsection{Version~4.0}
-With version~4.0 some changes have been made:
-\begin{itemize}
-  \item first of all the packages \chemformula\ and \ghsystem\ do not load
-    \chemmacros\ any more which means they can be used independently.
-  \item the option \option{bpchem} has been dropped.
-  \item the commands \cs{mch} and \cs{pch} now match \chemformula's
-    charges.
-  \item the option \option{method} has been dropped.
-  \item the option \option{append} has deprecated.
-  \item the option \option{greek} has been extended to support other uppercase
-    greek letters, for example those provided by \pkg{kpfonts}.  This is
-    handled internally by the new package in the family: \chemgreek.  This
-    package is not really a package for usage at a user-level but could in
-    principle be used to extend the \option{greek} option.
-  \item language support is now done with the help of the \pkg{translations}.
-    This means that with version~4.0  the document language is recognized
-    automatically.
-  \item the status of the commands \cs{Lfi} and \cs{Dfi} has been changed
-    from \emph{deprecated} to \emph{dropped}.
-  \item various other changes like bug fixes and improvements on the
-    typographical appearance of \chemformula's inline formulae with \cs{ch}.
+    \code{\cs*{textit}\Marg{o}-dichlorobenzene}); the first variant in my
+    opinion also is more in the spirit of \LaTeXe.
+  \item As much customizability as I could think of so every user can adapt
+    the commands to his or her own wishes.  Every now an then users have
+    wishes which can't be solved with the available options.  Almost always
+    I'll add options then.  If you find something please contact me, see
+    section~\vref{sec:sugg-bug-reports}.
+  \item Default settings that are compliant with the recommendations of the
+    \acf{iupac}.
 \end{itemize}
+Especially the last point in the past needed some pushing from users to get
+things right in many places.  If you find anything not compliant with
+\ac{iupac} recommendations please contact me, see
+section~\vref{sec:sugg-bug-reports}.  Don't forget to add references for the
+corresponding \ac{iupac} recommendation.
+
+\section{The Structure of \chemmacros}\label{sec:structure-chemmacros}
+\subsection{General Structure}
+Since version~5.0 the \chemmacros\ package has a strictly modular
+structure\sinceversion{5.0}.  On the one hand this eases maintenance but it
+will also allow for easy and quick extension in the future.  In a way it is a
+logical consequence from \chemmacros' history: since version~2.0, \ie, since
+the fall of~2011 \chemmacros\ already had modular options.
+
+The different modules of \chemmacros\ are divided into two groups:
+\begin{enumerate}
+  \item Internal modules which provide underlying functionality or basic
+    functionality which is not of direct interest from a user perspective but
+    might be if you plan to write a module yourself (see
+    section~\ref{sec:own-modules} for details).
+  \item User modules which provide all the stuff for typesetting.
+\end{enumerate}
+Both groups each are subdivided into two groups: preloaded modules and modules
+which have to be loaded by the programmer (internal modules) or by the
+document author (user modules).  Those modules are described in
+parts~\ref{part:preloaded-modules} (preloaded modules)
+and~\ref{part:additional-modules} (additional modules) of this manual.
+
+The above means that not all functionality is available per default.  If you
+want to load \emph{all} modules no matter what then you can say:
+\begin{sourcecode}
+  \usechemmodule{all}
+\end{sourcecode}
+or
+\begin{sourcecode}
+  \chemsetup{modules=all}
+\end{sourcecode}
+which will load all modules which are part of \chemmacros\ (also see
+section~\vref{sec:all-module}). Own modules (see
+section~\vref{sec:own-modules}) are \emph{not} loaded through this, though,
+and still have to be loaded additionally.
+
+In part~\vref{part:preloaded-modules} the preloaded modules are described,
+first the user modules then the internal ones, in
+part~\vref{part:additional-modules} the other available modules are described,
+again the user modules first.  In each section the modules are described in
+an alphabetical order.
+
+\subsection{Using \chemmacros' Options}\label{sec:using-chemm-opti}
+Prior to v5.0 \chemmacros\ had quite a number of package options.
+\chemmacros\ v5.0 or higher has none!  All of \chemmacros's options are set
+using the command
+\begin{commands}
+  \command{chemsetup}[\oarg{module}\marg{option list}]
+    \chemmacros' setup command.
+\end{commands}
 
-\subsection{Version~4.2}
+When an option is described then in the left margin the module the option
+belongs to is denoted.  This looks something like this:
+\begin{options}
+  \keyval{option}{value}\Module{module}\Default
+    Description of \option{option}. The module is printed in the left margin.
+    The default value to the right is the setting the option has when
+    \chemmacros\ is loaded.  This can be an explicit setting but the option
+    can also be empty.
+  \keychoice{choice-option}{list,of,\default{choices}}\Module{module}\Default{list}
+    Description of \option{choice-option}.  A choice option can only be used
+    with a predefined list of values. If one of the values is underlined it
+    means that the option can be used without value in which case the
+    underlined value is chosen.  If no value is underlined then a value
+    \emph{has} to be given by the user.
+  \keybool{boolean-option}\Module{module}\Default{true}
+    Description of \option{boolean-option}.  A boolean option is a choice
+    option with exactly the two values \code{true} and \code{false}.  If the
+    option is called without value then the underlined value is chosen (which
+    is always \code{true} for a boolean option).
+\end{options}
 
+An option or list of options belonging to a module \chemmodule{module} can be
+set in two ways:
+\begin{sourcecode}
+  % first possibility:
+  \chemsetup[module]{
+    option1 = value ,
+    option2 = value
+  }
+  % second possibility:
+  \chemsetup{
+    module/option1 = value ,
+    module/option2 = value
+  }
+\end{sourcecode}
+The second way allows to set options belonging to different modules with one
+call of \cs{chemsetup}.
+
+\subsection{Support Package \chemformula}
+\chemformula\ provides means of typesetting chemical formulas and reactions.
+You will see its macros \cs{ch} and \cs{chcpd} every now and then in this
+manual.  When using \chemmacros\ you can consider the \chemformula\
+package~\cite{pkg:chemformula} to be loaded as \chemmacros\ makes use of it in
+various places.  \chemmacros\ and \chemformula\ are tightly intertwined.  In
+fact: \emph{when using \chemmacros\ you should prefer \chemformula\ over
+  \pkg{mhchem} (which provides very similar functionality) for having
+  consistent typesetting}.
+
+A historical note: \chemformula\ started as a part of \chemmacros\ in
+January~2012.  Since July~2013 it is a completely independent package -- from
+\chemformula's point of view.  It is maintained independently and has a manual
+of its own.
+
+\subsection{Upgrading from version $<5.0$}
+People upgrading from versions $<5.0$ will find that almost everything they
+know from earlier versions is the same in versions $\geq5.0$.  But there are
+important and \emph{breaking} differences:
 \begin{itemize}
-  \item Changed particles with electron pairs such as \cs{ba} to use
-    \chemformula's new macro \cs{chlewis} for the Lewis electrons.
-  \item Changed the implicit \cs*{Delta} in the thermodynamic state variables
-    into \cs*{ChemDelta} to ensure that an upright symbol is used.
-  \item Change in the syntax of \cs{DeclareChemState} and
-    \cs{RenewChemState}.  The old syntax is still supported but discouraged.
+  \item \chemmacros\ has no package options any more, all options are set via
+    \cs{chemsetup}, also see section~\vref{sec:using-chemm-opti}.
+  \item Not all of the features are available per default any more, for some
+    the corresponding module has to be loaded explicitly, see
+    section~\ref{sec:general-options}.  If suddenly some commands or
+    environments seem to be undefined this is the most likely reason.
+  \item Some option modules have been renamed (\eg, \module*{iupac} is now
+    \module{nomenclature}).  If you experience strange errors when you upgrade
+    your document this is the most likely source.
+  \item The command family \cs*{NewChem\ldots}, \cs*{RenewChem\ldots} and
+    \cs*{DeclareChem\ldots} has a new member \cs*{ProvideChem\ldots}.
+  \item In \cs{iupac} the macro \cs*{-} no longer gives a dash with breaking
+    point.  Instead \sym*{-} can be used directly\footnote{\cs*{-} will be
+      provided a bit longer for easing the upgrade step but will be dropped
+      eventually.}.
+  \item The macro \cs{ox} has another default behaviour (\keyis{pos}{super})
+    and the starred version has another effect (\keyis{pos}{top}) than the
+    same macro in earlier versions.  Now the default behaviour follows
+    \acs{iupac} recommendations.  A second change is that the atom is now
+    treated as a \chemformula\ formula.
+  \item The syntax of \cs{NewChemReaction} and friends is now different from
+    what it used to be.  If you have defined your own reaction environments
+    you need to adapt!
+  \item \chemmacros\ offers a macro \cs{state} which is similar to but
+    different from the earlier macro \cs*{State}.  \cs*{State} is deprecated.
+    There are also differences in the syntax of \cs{enthalpy} \vs\ the earlier
+    \cs*{Enthalpy}, \cs{entropy} \vs\ \cs*{Entropy} and \cs{gibbs} \vs\
+    \cs*{Gibbs}.  The uppercase versions are deprecated. The  macro
+    \cs{NewChemState} also has a different syntax now.
+  \item At various places in the code improvements and fixes have been made,
+    too many to list them here.  You should keep an open eye and first of all
+    read the manual closely.
 \end{itemize}
 
-\subsection{Version 4.3}
-\begin{itemize}
-  \item All one-letter \acs{iupac} macros have been exchanged in favour of
-    more meaningful macro names.  The one-letter commands still exist for
-    backward compatibility (and to some users no doubt also for convenience).
-    They are no longer recommended though.  One-letter commands seldomly have
-    meaningful names and  often they've also been defined by other packages.
-    This means they make collaboration more difficult than it needs to be and
-    are a source for package conflicts.  \chemmacros\ used to solved the
-    latter problem by only providing them inside the argument of
-    \cs{iupac}\label{desc:one-letter-commands}.  The one exception
-    \chemmacros\ makes is the command \cs{p} (for things like \pH) which is
-    and will remain an official command.
-  \item The environment \env{experimental} has got a number of new options,
-    see section~\ref{sec:experimental-customization}.
-  \item The commands \cs*{DeclareChem\meta{...}} now don't give an error any
-    more if the command already exists.  This is more consistent with \LaTeX's
-    \cs*{DeclareRobustCommand}.  For all those commands a version
-    \cs*{NewChem\meta{...}} is introduced that \emph{does} give an error if
-    the new command is already defined.
-  \item The package option \option{strict} has been deprecated.
-  \item The package option \option{cmversion} has been deprecated.
-  \item The command \cs{mhName} has been dropped.
-\end{itemize}
+\subsection{Compatibility Mode}
 
-\subsection{Version 4.4}
-\begin{itemize}
-  \item New \module{nmr} option \option{atom-number-cs}.
-  \item New \module{nmr} option \option{coupling-pos-cs}.
-\end{itemize}
+\subsubsection{For Users}
+It is actually not true that \chemmacros' has no package options any more.  It
+has one very important package option:
+\begin{options}
+  \keyval{compatibility}{num}\Default{\chemmacrosversion}
+    Let's you specify the version number of \chemmacros\ you want to use.  Any
+    version earlier than 5.0 will load v4.7. \ie, the last version before
+    \chemmacros\ got its modular structure\footnote{Mostly: the loaded v4.7
+      has got a few fixes}.  Not using the option will always load the newest
+    version.  Please note that you only can specify the \emph{number} of the
+    version.  For a version \enquote{5.2c} you can only set compatibility mode
+    \enquote{5.2} but not specify the subrelease.
+\end{options}
 
-\subsection{Version 4.5}
-\begin{itemize}
-  \item New \module{acid-base} option \option{subscript}.
-  \item Dutch translations.
-\end{itemize}
+In your document you can check for the compatibility mode.  For the following
+functions it is important to understand the rules: \emph{greater} means
+\emph{newer}.  The version number is \emph{not} a usual decimal number!  The
+syntax for \meta{num} is \meta{major}\code{.}\meta{minor}.  This means that a
+version 5.11 is \emph{newer} than a version 5.7!  In the same way \emph{less}
+means \emph{older}.  As last example: 5.10 is \emph{newer} (greater) than 5.1.
+\begin{commands}
+  \command{IfChemCompatibilityTF}[\marg{comp}\marg{num}\marg{true}\marg{false}]
+    Checks the value given through the option \option{compatibility} against
+    \meta{num} using \meta{comp} and either leaves \meta{true} or \meta{false}
+    in the input stream. \meta{comp} can be one of \code{<}, \code{<=},
+    \code{=}, \code{>=} or \code{>}.
+  \command{IfChemCompatibilityT}[\marg{comp}\marg{num}\marg{true}]
+    Checks the value given through the option \option{compatibility} against
+    \meta{num} using \meta{comp} and leaves \meta{true} in the input stream if
+    the check is logically true.  \meta{comp} can be one of \code{<},
+    \code{<=}, \code{=}, \code{>=} or \code{>}.
+  \command{IfChemCompatibilityF}[\marg{comp}\marg{num}\marg{false}]
+    Checks the value given through the option \option{compatibility} against
+    \meta{num} using \meta{comp} and leaves \meta{false} in the input stream if
+    the check is logically false.  \meta{comp} can be one of \code{<},
+    \code{<=}, \code{=}, \code{>=} or \code{>}.
+\end{commands}
 
-\subsection{Version 4.6}
-\begin{itemize}
-  \item The packages \chemformula, \chemgreek{} and \ghsystem{} are no longer
-    distributed as a part of \chemmacros{} but as packages of their own.
-  \item Inside \cs{iupac} the characters \code{\textbar} and
-    \code{\textasciicircum} are active.  The corresponding commands
-    \cs{\textbar} and \cs{\textasciicircum} are deprecated now and will be
-    dropped eventually.
-\end{itemize}
+A possible usage:
+\begin{sourcecode}
+  \IfChemCompatibilityT{>=}{5.0}{\usechemmodule{all}}
+\end{sourcecode}
 
-\subsection{Version 4.7}
-\begin{itemize}
-  \item Fix broken \cs{iupac}.
-  \item Change the default subscripts of the equilibrium constants to match
-    the usage in the \acs{iupac} Green Book.
-  \item Allow \cs{NewChemPhase} and friends after \verbcode+\begin{document}+.
-  \item New optional argument to phase commands.
-  \item New \module{nmr} options n\option{method} and \option{connector}.
-\end{itemize}
+Loading \chemmacros\ with \keyis{compatibility}{4.7} also allows to use the
+package options from that version:
+\begin{sourcecode}
+  \usepackage[compatibility=4.7,language=german]{chemmacros}
+\end{sourcecode}
+
+\subsubsection{For Module Writers}
+For future versions the aim is not to make such breaking changes again.  While
+we never know what the future actually will bring \chemmacros\ now has the
+tools for tying code to a version number:
+\begin{commands}
+  \expandable\command*{chemmacros_if_compatiblity:nn}[\TF\ \marg{comp}
+  \marg{num} \marg{true} \marg{false}]
+    expl3 version of \cs{IfChemCompatibilityTF}.
+\end{commands}
 
-\section{Package Options}\label{sec:options}
-\chemmacros\ has several package options. They all are used as key/value pairs
-like
+In modules one can try adding code for a certain version or range of versions:
+\begin{commands}
+  \command{ChemCompatibility}[\marg{num} \meta{code} \cs{EndChemCompatibility}]
+    Leaves \meta{code} in the input stream if the compatibility version $x$
+    given by \option{compatibility} matches \meta{num}
+    ($x=\text{\meta{num}}$).
+  \command{ChemCompatibilityFrom}[\marg{num} \meta{code} \cs{EndChemCompatibility}]
+    Leaves \meta{code} in the input stream if the compatibility version $x$
+    given by \option{compatibility} matches \meta{num} or newer.  This means
+    \meta{num} is the \emph{oldest} version allowed
+    ($x\geq\text{\meta{num}}$).
+  \command{ChemCompatibilityTo}[\marg{num} \meta{code} \cs{EndChemCompatibility}]
+    Leaves \meta{code} in the input stream if the compatibility version $x$ given
+    by \option{compatibility} matches \meta{num} or older.  This means
+    \meta{num} is the \emph{newest} version allowed
+    ($x\leq\text{\meta{num}}$).
+  \command{ChemCompatibilityBetween}[\marg{num1}\marg{num2} \meta{code}
+  \cs{EndChemCompatibility}]
+    Leaves \meta{code} in the input stream if the compatibility version $x$
+    given by \option{compatibility} lies between \meta{num2} and \meta{num2}
+    ($\text{\meta{num1}}\leq x\leq\text{\meta{num2}}$).
+  \command{EndChemCompatibility}
+    This macro \emph{must} end each of the \cs*{ChemCompatibility\ldots}
+    macros.
+\end{commands}
+
+You may refer to the current version of \chemmacros\ with the following
+tokenlists:
+\begin{commands}
+  \command*{c_chemmacros_date_tl}
+    The current release date: \enquote{\csname
+      c_chemmacros_date_tl\endcsname}.
+  \command*{c_chemmacros_version_major_number_tl}
+    The current major version: \enquote{\csname
+    c_chemmacros_version_major_number_tl\endcsname}.
+  \command*{c_chemmacros_version_minor_number_tl}
+    The current minor version: \enquote{\csname
+    c_chemmacros_version_minor_number_tl\endcsname}.
+  \command*{c_chemmacros_version_number_tl}
+    The current version number: \enquote{\csname
+    c_chemmacros_version_number_tl\endcsname}.
+  \command*{c_chemmacros_version_subrelease_tl}
+    The current sub-release: \enquote{\csname
+    c_chemmacros_version_subrelease_tl\endcsname}.
+  \command*{c_chemmacros_version_tl}
+    The current version: \enquote{\csname c_chemmacros_version_tl\endcsname}.
+  \command*{c_chemmacros_info_tl}
+    The package information: \enquote{\csname
+      c_chemmacros_info_tl\endcsname}.
+\end{commands}
+
+\section{General Options}\label{sec:general-options}
+
+\chemmacros\ has some core options which don't belong to any of the modules
+described in parts~\ref{part:preloaded-modules}
+and~\ref{part:additional-modules}.  Those options have no module denoted in
+the left margin next to their descriptions and are also set without specifying
+a module:
 \begin{sourcecode}
-  \usepackage[option1 = <value1>, option2 = <value2>]{chemmacros}
+  \chemsetup{
+    option1 = value ,
+    option2 = value
+  }
 \end{sourcecode}
-Some also can be used without value
-(\verbcode+\usepackage[option1]{chemmacros}+), which means that the
-\default{underlined} value is used.
 
+Two of those options are explained now:
 \begin{options}
-  % circled
-  \keychoice{circled}{formal,\default{all},none}\Module{option}\Default{formal}
-    \chemmacros\ uses two different kinds of charges which indicate the usage
-    of real ($+/-$) and formal (\fplus/\fminus) charges.  The option
-    \code{formal} distinguishes between them, option \code{none} displays them
-    all without circle, option \code{all} circles all.
-  % circletype
-  \keychoice{circletype}{\default{chem},math}\Module{option}\Default{chem}
-    This option switches between two kinds of circled charge symbols:
-    \cs{fplus} \fplus\ and \verbcode+$\oplus$+ $\oplus$.
-  % ghsystem
-  \keybool{ghsystem}\Module{option}\Default{false}
-    \keyis{ghsystem}{false} disables the automatic loading of the \ghsystem\
-    package.
-  % greek
-  \keychoice{greek}{\default{auto},upgreek,textgreek,mathdesign,kpfonts,newtx,%
-      fourier,textalpha}\Module{option}{}% empty group pushes default value to
-                                         % next line
-    \Default{auto}
-    This option determines how the letters \cs{chemalpha} and friends are
-    typeset.  See pages~\pageref{desc:greek} and~\pageref{par:greek_letters}
-    for more information.  Please note that this option \emph{does not load
-      either \pkg{upgreek}, \pkg{kpfonts} or any other package!}  It only
-    determines which one to choose if available.  The option \code{auto} will
-    detect if any of the packages needed for one of the options has been
-    loaded and use it if available.  If more than one of the packages has been
-    loaded the option will choose the one listed first in the above choice
-    list.  If you explicitly choose an option other than \code{auto} or
-    \code{math} you also have to load the corresponding package.  \emph{This
-      option can only be chosen in the preamble}.
-  % iupac
-  \keychoice{iupac}{auto,restricted,strict}\Module{option}\Default{auto}
-    Take care of how \ac{iupac} naming commands are defined, see
-    page~\pageref{desc:iupac}.
-  % language
-  \keychoice{language}{american,british,english,french,german,italian,ngerman}%
-    \Module{option}\Default
-    Load the language used by \chemmacros.  \emph{This option can only be
-      chosen in the preamble}.
-  % Nu
-  \keychoice{Nu}{\default{chemmacros},mathspec}\Module{option}\Default{chemmacros}
-    The package \pkg{mathspec} also defines a macro \cs{Nu}.  This option
-    chooses which definition holds, see page~\pageref{Nu}.  \emph{This option
-      can only be chosen in the preamble}.
-  % synchronize
-  \keybool{synchronize}\Module{option}\Default{false}
-    The setting \code{true} will tell \chemmacros\ to adapt the font settings
-    of \chemformula.
-  % xspace
-  \keybool{xspace}\Module{option}\Default{true}
-    With this option most commands are defined with a \cs*{xspace}.
+  \keyval{modules}{comma separated list of module names}\Default
+    With this option you can specify which modules you want to load.
+    Alternatively you can use \cs{usechemmodule}\marg{comma separated list of
+      module names}.
+  \keyval{greek}{mapping}\Default
+    Explicitly specify which mapping should be used by the \chemgreek\
+    package~\cite{pkg:chemgreek}.  For details about what this means please
+    refer to section~\vref{sec:greek-module}.
 \end{options}
 
+Some internal modules may also define core options, \eg, the \chemmodule{lang}
+module, see section~\vref{sec:lang-module}.
 
-\section{Setup}\label{sec:setup}
-Various of \chemmacros' commands have key/value pairs with which they can be
-customized.  Most times they can be used as (optional) argument of the
-commands themselves.  They also can most times be used with the \cs{chemsetup}
-command.
+\part{The Preloaded Modules}\label{part:preloaded-modules}
+
+\section{User Modules}
+\subsection{The \chemmodule*{acid-base} Module}\label{sec:acid-base-module}
+
+Easy representation of \pH, \pKa \ldots
 \begin{commands}
-  \command{chemsetup}[\oarg{module}\Marg{\meta{key} = \meta{value}}]
-    Set up the options for module \meta{module} only or
-  \command{chemsetup}[\Marg{\meta{module}/\meta{key} = \meta{value}}]
-    in combination with options from other modules.
+  \command{pH} \pH
+  \command{pOH} \pOH
+  \command{Ka} \Ka, depends on language settings, see
+    section~\vref{sec:lang-module}.  The translations can be adapted.
+  \command{Kb} \Kb
+  \command{Kw} \Kw
+  \command{pKa}[\oarg{num}] \cs{pKa}: \pKa, \cs{pKa}\Oarg{1}: \pKa[1], depends
+    on language settings, see  section~\vref{sec:lang-module}.  The translations
+    can be adapted.
+  \command{pKb}[\oarg{num}] \cs{pKb}: \pKb, \cs{pKb}\Oarg{1}: \pKb[1]
+  \command{p}[\marg{anything}] \eg\ \cs{p}\Marg{\cs{Kw}} \p{\Kw}
 \end{commands}
-The keys each belong to a module, which defines for which commands they are
-intended for.  If a key is presented, you'll see the module to which it
-belongs in the left margin.  You have two ways to use keys with the
-\cs{chemsetup}, as you can see above.
-
-The package options can also be seen as keys belonging to the module
-\module{option}.  This means they can also be used with the \cs{chemsetup}
-command (except for the option \choicekey{version}{1,2,3}).
+
+\begin{example}[side-by-side]
+  \Ka\ \Kb\ \pKa\ \pKa[1] \pKb\ \pKb[1]
+\end{example}
+
+\begin{cnltxquote}[{\citetitle{iupac:greenbook} \cite[][p.\,103]{iupac:greenbook}}]
+ The operator \p{} \textelp{} shall be printed in Roman type.
+\end{cnltxquote}
+
+There is one option which changes the style the \p{} is typeset, other options
+allow to change the subscript of the constants:
+\begin{options}
+  \keychoice{p-style}{italics,slanted,upright}\Module{acid-base}\Default{upright}
+    Set the style of the \p{} operator.
+  \keyval{K-acid}{text}\Module{acid-base}\Default{\cs{ChemTranslate}\Marg{K-acid}}
+    The subscript to \cs{Ka} and \cs{pKa}.
+  \keyval{K-base}{text}\Module{acid-base}\Default{\cs{ChemTranslate}\Marg{K-base}}
+    The subscript to \cs{Kb} and \cs{pKb}.
+  \keyval{K-water}{text}\Module{acid-base}\Default{\cs{ChemTranslate}\Marg{K-water}}
+    The subscript to \cs{Kw}.
+\end{options}
 \begin{example}
-  \chemsetup[option]{circled=none}
-    \leavevmode\mch\ \pch\ \fmch\ \fpch\ \el\ \prt \par
-  \chemsetup[option]{circled=formal}
-    \leavevmode\mch\ \pch\ \fmch\ \fpch\ \el\ \prt \par
-  \chemsetup[option]{circletype=math}
-    \leavevmode\mch\ \pch\ \fmch\ \fpch\ \el\ \prt \par
-  \chemsetup{option/circletype=chem,option/circled=all}%
-    \leavevmode\mch\ \pch\ \fmch\ \fpch\ \el\ \prt \par
-  \chemsetup{option/circletype=math}
-    \leavevmode\mch\ \pch\ \fmch\ \fpch\ \el\ \prt
-\end{example}
-Keys \emph{not} belonging to a module \emph{cannot} be used with
-\cs{chemsetup}!
-
-All options of \chemformula\ belong to the module \module{chemformula} and all
-of \ghsystem's options belong to the module \module{ghsystem} which means that
-their options can also be set up using \cs{chemsetup}.
-
-
-\section{Language Settings}\label{sec:languages}
-\subsection{How it Works}
-\chemmacros\ uses the \pkg{translations} package for a number of language
-dependent strings.  That means that if a suitable translation to those strings
-is given the \pkg{babel}~\cite{pkg:babel} or
-\pkg{polyglossia}~\cite{pkg:polyglossia} language will be picked up
-automatically.  You can, however, overwrite this mechanism by explicitly
-chosing the language you want.  This is done with the package option
-\option{language}.
-
-Section~\ref{sec:supported-languages} lists all language dependent strings and
-the provided translations.
-
-\subsection{Supported Languages}\label{sec:supported-languages}
-By choosing the option
-\begin{commands}
-  \command{chemsetup}[\oarg{option}\Marg{language=\meta{language}}]
-    Selection of the language \meta{language}.
-\end{commands}
-you can set the language that is used by \chemmacros\ if you want it to be a
-\emph{different language than your main document language}.
+  \pH, \pKa \par
+  \chemsetup[acid-base]{p-style=slanted} \pH, \pKa \par
+  \chemsetup[acid-base]{p-style=italics} \pH, \pKa
+\end{example}
 
-There are some language definitions made by \chemmacros.  They include
-\begin{itemize}
-  \item the header of the list of reactions,
-  \item the beginning of the entries in the list of reactions, and
-  \item the H- and P-statements of the \ac{ghs} statements.
-\end{itemize}
+As you can see the default subscripts of \cs{Kw}, \cs{Ka} and \cs{Kb} are
+lowercase letters.  The literature is inconclusive about if this is the right
+way or if uppercase letters should be preferred.  In textbooks the uppercase
+variant usually seems to be used while journals seem to prefer the lowercase
+variant.  \chemmacros' default follows the usage in
+\citetitle{iupac:greenbook}~\cite{iupac:greenbook}.  If you want to change
+this you have two possibilities:
 
-\chemmacros\ uses the \pkg{translations} to get translated strings sensitive
-to \pkg{babel} or \pkg{polyglossia} settings.  All pre-defined
-\pkg{translations} keys are listed in
-table~\ref{tab:language-dependent-strings}.  To some of those a few
-non-English translations are provided.
+\begin{example}
+  % this works only in the preamble:
+  % \DeclareTranslation{English}{K-acid}{\mathrm{A}}% use your language here
+  % alternative:
+  \chemsetup{acid-base/K-acid=\mathrm{A}}% overwrites language dependent settings
+  \pKa
+\end{example}
 
-\begin{table}
-  \centering
-  \caption{Language dependent strings.}
-  \label{tab:language-dependent-strings}
-  \begin{tabular}{>{\ttfamily}ll}
-    \toprule
-      \normalfont\bfseries \pkg{translations} key &
-      \bfseries English default \\
-    \midrule
-      K-acid  & $\GetTranslation{K-acid}$ \\
-      K-base  & $\GetTranslation{K-base}$ \\
-      K-water & $\GetTranslation{K-water}$ \\
-    \midrule
-      phase-sld & \GetTranslation{phase-lqd} \\
-      phase-lqd & \GetTranslation{phase-sld} \\
-      phase-gas & \GetTranslation{phase-gas} \\
-      phase-aq  & \GetTranslation{phase-aq} \\
-    \midrule
-      list-of-reactions & \GetTranslation{list-of-reactions} \\
-      reaction          & \GetTranslation{lor-reaction} \\
-    \bottomrule
-  \end{tabular}
-\end{table}
+\subsection{The \chemmodule*{charges} Module}\label{sec:charges-module}
 
-Currently this includes the following translations:
-\begin{sourcecode}
-  % subscript used in \Ka:
-  \DeclareTranslation{German}{K-acid}{\mathrm{s}}
-  % the phases \sld and \lqd:
-  \DeclareTranslation{German}{phase-sld}{f}
-  \DeclareTranslation{German}{phase-lqd}{f{}l}
-  % heading of the list of reactions:
-  \DeclareTranslation{English}{list-of-reactions}{List of reactions}
-  \DeclareTranslation{German} {list-of-reactions}{Reaktionsverzeichnis}
-  \DeclareTranslation{Italian}{list-of-reactions}{Elenco delle reazioni}
-  \DeclareTranslation{French} {list-of-reactions}{Table des r\'eactions}
-  % name at the beginning of each entry in the list of reactions:
-  \DeclareTranslation{English}{reaction}{Reaction}
-  \DeclareTranslation{German} {reaction}{Reaktion}
-  \DeclareTranslation{Italian}{reaction}{Reazione}
-  \DeclareTranslation{French} {reaction}{R\'eaction}
-\end{sourcecode}
-All other languages will fall back to English.  However, you can always add
-the translation you want.  If you send me an email with translations you'd
-like to have added to \chemmacros\ I'll gladly add them.
-
-\subsection{Specialties}
-\subsubsection{German}
-If you choose \code{german/ngerman} the phase commands \cs{sld} and \cs{lqd}
-and the command \cs{pKa} are translated.
-
-\subsubsection{Italian}
-\NewChemIUPAC{\ter}{\textit{ter}}\NewChemIUPAC{\sin}{\textit{sin}}%
-Choosing the language \code{italian} defines two additional \ac{iupac} commands:
+The \chemmodule{charges} module loads the module \chemmodule{chemformula}.
+
+\subsubsection{Charge Symbols}
 \begin{commands}
-  \command{ter} \iupac{\ter}
-  \command{sin} \iupac{\sin}
+  \command{fplus} \fplus\ formal positive charge
+  \command{fminus} \fminus\ formal negative charge
+  \command{scrp} \scrp\ scriptstyle positive charge (\eg, for usage in
+    \pkg{chemfig}'s~\cite{pkg:chemfig} formulas).
+  \command{scrm} \scrm\ scriptstyle negative charge (\eg, for usage in
+    \pkg{chemfig}'s formulas).
+  \command{fscrp} \fscrp\ scriptstyle formal positive charge (\eg, for usage
+    in \pkg{chemfig}'s formulas).
+  \command{fscrm} \fscrm\ scriptstyle formal negative charge (\eg, for usage
+    in \pkg{chemfig}'s formulas).
+  \command{fsscrp} \fsscrp\ scriptscriptstyle formal positive charge (\eg, for
+    usage in \pkg{chemfig}'s formulas).
+  \command{fsscrm} \fsscrm\ scriptscriptstyle formal negative charge (\eg, for
+    usage in \pkg{chemfig}'s formulas).
 \end{commands}
 
-\part{The Package's Features}\label{part:chemmacros}
-\section{Particles, Ions and Symbols}\label{sec:particles}
-\subsection{Predefined}
+\subsubsection{Ion Charges}\label{sec:ion-charges}
+Simple displaying of (real) charges.  It is worth noting that these commands
+really are relicts from a time when \chemmacros\ tried hard to be compliant
+with \pkg{mhchem} and \chemformula\ didn't exist, yet.  They are still
+provided for backwards compatibility but \emph{my recommendation is to use}
+\cs{ch} (see the documentation of the \chemformula\
+package~\cite{pkg:chemformula}) \emph{and forget about these commands:}
+\begin{commands}
+  \command{pch}[\oarg{number}]
+    positive charge
+  \command{mch}[\oarg{number}]
+    negative charge
+  \command{fpch}[\oarg{number}]
+    formal positive charge
+  \command{fmch}[\oarg{number}]
+    formal negative charge
+\end{commands}
+\begin{example}[side-by-side]
+  A\pch\ B\mch[3] C\fpch[2] D\fmch
+\end{example}
 
-\chemmacros\ defines some simple macros for displaying often needed particles
-and symbols.  Please note, that they're displayed differently depending on the
-package options used, see section~\ref{sec:options}.  These commands can be
-used in text as well as in math mode.  Note that they are not meant to be used
-in \chemformula's \cs{ch}.
+\subsubsection{Partial Charges and Similar Stuff}\label{sec:part-charg-simil}
 
+The next ones probably are seldomly needed but nevertheless useful:
 \begin{commands}
-  \command{Hpl} \Hpl\ (proton)
-  \command{Hyd} \Hyd\ (hydroxide)
-  \command{HtO} \HtO\ (oxonium ion) (\textbf{H} \textbf{t}hree \textbf{O})
-  \command{water} \water
-  \command{el} \el\ (electron)
-  \command{prt} \prt\ (proton)
-  \command{ntr} \ntr\ (neutron)
-  \command{Nu} \Nu\ (nucleophile)\par
-    The package \pkg{mathspec} also defines a macro \cs{Nu}.  If you chose
-    package option \keyis{Nu}{mathspec} \chemmacros\ defines \cs{Nuc}
-    instead\label{Nu}.
-  \command{El} \El\ (electrophile)
-  \command{ba} \ba\ (base)
-  \command{fplus} \fplus
-  \command{fminus} \fminus
-  \command{transitionstatesymbol} \transitionstatesymbol
-  \command{standardstate} \standardstate\par
-    This symbol is only provided by \chemmacros, if the package
-    \pkg{chemstyle} is not loaded; the idea is borrowed from
-    there\footnote{many thanks to the package author
-      \href{http://www.texdev.net/}{Joseph Wright}.}.
-  \command{changestate} $\changestate$\par
-    A math operator symbol for denoting the change in an extensive
-    thermodynamic quantity for a process such as \State{H}.  This symbol is
-    used in the definitions presented in section~\ref{sec:stand-state-therm}.
-  \command{chemalpha}[ \chemalpha, \cs{chemAlpha} \chemAlpha]
-    For each of the 24 greek letters a lowercase and uppercase \cs*{Chem...}
-    command is defined that maps to the upright greek letter as set with the
-    option \option{greek}.  More details on this can be found in the manual of
-    the \chemgreek\ package.
+  \command{delp} \delp\ partial positive charge
+  \command{delm} \delm\ partial negative charge
+  \command{fdelp} \fdelp\ partial formal positive charge
+  \command{fdelm} \fdelm\ partial formal negative charge
 \end{commands}
 
-The two particles \cs{Nu} and \cs{ba} can be modified.  To do that you use
-the option
+These macros for example can be used with the \cs{ox} command (see
+section~\vref{sec:redox-module}) or with the \pkg{chemfig} package:
+\begin{example}
+  \chemsetup{
+    charges/circled = all,
+    redox/parse     = false,
+    redox/pos       = top
+  }
+  \ch{"\ox{\delp,H}" -{} "\ox{\delm,Cl}"} \hspace*{1cm}
+  \chemfig{\chemabove[3pt]{\lewis{246,Br}}{\delm}-\chemabove[3pt]{H}{\delp}}
+\end{example}
+
+\subsubsection{Charge Options}
+
 \begin{options}
-  \keychoice{elpair}{false,\default{dots},dash}\Module{particle}\Default{false}
-    Set how the electron pair of the particles \cs{Nu} and \cs{ba} are set.
+  \keychoice{circled}{formal,\default{all},none}\Module{charges}\Default{formal}
+    \chemmacros\ uses two different kinds of charges which indicate the usage
+    of real ($+/-$) and formal (\fplus/\fminus) charges.  The option
+    \code{formal} distinguishes between them, option \code{none} displays them
+    all without circle, option \code{all} circles all.
+  \keychoice{circletype}{chem,math}\Module{charges}\Default{chem}
+    This option switches between two kinds of circled charge symbols:
+    \cs{fplus} \fplus/\cs{fminus} \fminus\ (\code{chem}) and
+    \verbcode+$\oplus$+ $\oplus$/\verbcode+$\ominus$+ $\ominus$ (\code{math}).
+  \keyval{partial-format}{\LaTeX\ code}\Module{charges}\Default{\cs*{tiny}}
+    Code which formats the macros defined with \cs{NewChemPartialCharge} (see
+    section~\ref{sec:own-charge-macros}).
 \end{options}
-\begin{example}[side-by-side]
-  \ba[elpair] \Nu[elpair=dash]
- 
-  \chemsetup[particle]{elpair}
-  \ba\ \Nu
-\end{example}
 
-\label{desc:greek}The greek letters aren't newly defined symbols but are
-defined differently depending on the packages you've loaded.  The default
-definition is the corresponding math letter.  If you have loaded the
-\pkg{textgreek} package the letters are taken from there, and if you have
-loaded the package \pkg{upgreek} the macros of that package are used.  This is
-also described in the description of the package option \option{greek}, other
-details can be found in the documentation of the \chemgreek\ package.  Which
-package you have to load for a specific choice for the package option
-\option{greek} is listed in table~\ref{tab:option:greek}.  This documentation
-uses \pkg{newtxmath} and the setting \keyis{greek}{newtx} for instance.
+\subsubsection{Own Charge Macros}\label{sec:own-charge-macros}
+Just in case the existing macros don't fit you needs there are commands for
+defining new ones or modifying the existing ones.  These commands define
+macros like those described in section~\vref{sec:ion-charges}.
 
-\begin{table}
-  \centering
-  \caption{Packages needed for the \option*{greek} package option..}
-  \label{tab:option:greek}
-  \begin{tabular}{>{\ttfamily}ll}
-    \toprule
-      \tablehead{option} & \tablehead{needed package} \\
-    \midrule
-      auto        & --- \\
-      math        & --- \\
-      textgreek   & \pkg{textgreek} \cite{pkg:textgreek} \\
-      upgreek     & \pkg{upgreek} \cite{pkg:upgreek} \\
-      newtx       & \pkg{newtxmath} \cite{pkg:newtx} \\
-      kpfonts     & \pkg{kpfonts} \cite{pkg:kpfonts} \\
-      mathdesign  & \pkg{mathdesign} \cite{pkg:mathdesign} \\
-      fourier     & \pkg{fourier} \cite{pkg:fourier} \\
-      textalpha   & \pkg{textalpha} \cite{bnd:greek-fontenc} \\
-    \bottomrule
-  \end{tabular}
-\end{table}
+\begin{commands}
+  \command{NewChemCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a new macro \meta{cs}. Raises an error if \meta{cs} already
+    exists.
+  \command{RenewChemCharge}[\marg{cs}\marg{charge symbol}]
+    Redefines a new macro \meta{cs}. Raises an error if \meta{cs} doesn't
+    exist.
+  \command{DeclareChemCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a macro \meta{cs}.  Silently overwrites \meta{cs} if it exists.
+  \command{ProvideChemCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a new macro \meta{cs}.  Does nothing if \meta{cs} already exists.
+\end{commands}
+An example of usage is the definition of the existing ion charge macros:
+\begin{sourcecode}
+  \NewChemCharge\fpch{\fplus}
+  \NewChemCharge\fmch{\fminus}
+\end{sourcecode}
 
-The reason why \chemmacros\ uses these macros in the first place is \ac{iupac}
-compliance.  \ac{iupac} recommends to use upright greek letters in
-nomenclature.
+These commands define macros like those described in
+section~\vref{sec:part-charg-simil}. 
+\begin{commands}
+  \command{NewChemPartialCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a new macro \meta{cs}. Raises an error if \meta{cs} already
+    exists.
+  \command{RenewChemPartialCharge}[\marg{cs}\marg{charge symbol}]
+    Redefines a new macro \meta{cs}. Raises an error if \meta{cs} doesn't
+    exist.
+  \command{DeclareChemPartialCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a macro \meta{cs}.  Silently overwrites \meta{cs} if it exists.
+  \command{ProvideChemPartialCharge}[\marg{cs}\marg{charge symbol}]
+    Defines a new macro \meta{cs}.  Does nothing if \meta{cs} already exists.
+\end{commands}
+An example of usage is the definition of the existing partial charge macros:
+\begin{sourcecode}
+  \NewChemPartialCharge\fdelp{\fplus}
+  \NewChemPartialCharge\fdelm{\fminus}
+\end{sourcecode}
 
-\begin{cnltxquote}[{\ac{iupac} Green Book {\cite[][p.\,9]{iupac:greenbook}}}]
-  Greek letters are used in systematic organic, inorganic, macromolecular and
-  biochemical nomenclature.  These should be roman (upright), since they are
-  not symbols for physical quantities.
-\end{cnltxquote}
+\subsection{The \chemmodule*{nomenclature} Module}\label{sec:nomenclature-module}
 
-\chemmacros\ uses these commands now to define nomenclature commands, see
-page~\pageref{par:greek_letters}.
+The \chemmodule{nomenclature} module loads the \chemmodule{tikz} module.  It
+also loads the package \pkg{scrlfile} which is part of the
+\KOMAScript\ bundle~\cite{bnd:koma-script}.
 
-\subsection{Own Particles}
+\subsubsection{The \cs*{iupac} Command}
 
-Surely sometimes it can be handy to have other particle macros defined such as
-\cs*{positron} or \cs*{photon}.  This can easily be done with this command:
-\begin{commands}
-  \command{NewChemParticle}[\marg{cs}\marg{definition}]
-    \sinceversion{4.3}Define a new particle command.  Gives an error if
-    \meta{cs} already exists.
-  \command{DeclareChemParticle}[\marg{cs}\marg{definition}]
-    \changedversion{4.3}Define a new particle command.
-  \command{RenewChemParticle}[\marg{cs}\marg{definition}]
-    Renew the definition of a particle command.
-\end{commands}
-The particle defined this way behaves uses \chemformula's \cs{ch} to typeset
-the particle which means that the \meta{definition} should be a vaild
-\chemformula\ compound.  Please have a look at the \chemformula\ manual for
-details.  The particle will obey the \option{circled} option.
-\begin{example}
-  \NewChemParticle\positron{\chembeta+}
-  \NewChemParticle\photon{\chemgamma}
-  \RenewChemParticle\el{\chembeta-}
-  \positron\ \photon\ \el
-\end{example}
-
-\section{Nomenclature, Stereo Descriptors, Latin Phrases}\label{sec:stereo}
-\subsection{\acs{iupac} Names}
-
-Similar to the \pkg{bpchem} package \chemmacros\ provides a
-command\footnote{The idea and the implementation is shamelessly borrowed from
-  \pkg{bpchem} by \pedersen.} to typeset \ac{iupac} names.  Why is
-that useful?  \ac{iupac} names can get very long.  So long indeed that they
-span over more than two lines, especially in two-column documents.  This means
-they must be allowed to be broken more than one time.  This is what the
-following command does.
+Similar to the \pkg{bpchem} package~\cite{pkg:bpchem} \chemmacros\ provides a
+command\footnote{The idea and initial implementation is shamelessly borrowed
+  from \pkg{bpchem} by \pedersen.} to typeset \ac{iupac} names.  Why is that
+useful?  \ac{iupac} names can get very long.  So long indeed that they span
+over more than two lines, especially in two-column documents.  This means they
+must be allowed to be broken more than one time.  This is what the following
+command does.
 \begin{commands}
   \command{iupac}[\marg{IUPAC name}]
-    Inside this command use \cs{\textbar} and \cs{-} to indicate a breaking
-    point or a breaking dash.  Use \cs{\textasciicircum} as a shortcut for
-    \cs*{textsuperscript}.  In fact, \sinceversion{4.6}since version~4.6 the
-    characters \code{\textbar} and \code{\textasciicircum} are active inside
-    \cs{iupac}. Using \code{\textbar} is equivalent to \cs{\textbar} and using
-    \code{\textasciicircum} is equivalent to \cs{\textasciicircum}.
+    Inside this command use \sym{\textbar} indicate a breaking point
+    \sym{\textasciicircum} as a shortcut for \cs*{textsuperscript}. \sym{-},
+    \sym{(} and \sym{)} allow words to be broken while still allow the rest of
+    word to be hyphenated, likewise \sym{[} and \sym{]}.
 \end{commands}
 
 \begin{example}
   \begin{minipage}{.4\linewidth}
     \iupac{%
-      Tetra|cyclo[2.2.2.1^{1,4}]\-un|decane-2\-dodecyl\-%
-      5\-(hepta|decyl|iso|dodecyl|thio|ester)%
+      Tetra|cyclo[2.2.2.1^{1,4}]-un|decane-2-dodecyl-%
+      5-(hepta|decyl|iso|dodecyl|thio|ester)%
     }
   \end{minipage}
 \end{example}
-The \cs{iupac} command is more of a semantic command.  Most times you can
-achieve (nearly) the same thing by using \cs{-} instead of \cs{\textbar},
-\code{-} instead of \cs{-} and \cs*{textsuperscript} instead of
-\cs{\textasciicircum}.
 
-There are some subtleties: \cs{-} inserts a small space before the hyphen and
-removes a small space after it.  The command \cs{\textbar} not only prevents
-ligatures but also inserts a small space.
+The \cs{iupac} command is more of a semantic command.  In many cases you can
+achieve (nearly) the same thing by using \cs*{-} instead of \sym{\textbar},
+and \cs*{textsuperscript} instead of \sym{\textasciicircum} without
+\cs{iupac}.  There are some important differences, though:
+\begin{itemize}
+  \item The character \sym{-} inserts a small space before the hyphen and
+    removes a small space after it.  Also usually words with hyphens are only
+    allowed to break at the hyphen.  Inside \cs{iupac} the hyphen will not
+    prevent further hyphenation.  The amount of inserted space can be
+    customized.
+  \item The character \sym{\textbar} not only prevents ligatures but also
+    inserts a small space.  The amount of inserted space can be customized.
+  \item The characters \sym{(} and \sym{)} allow the word to be hyphenated and
+    don't prevent further hyphenation, likewise \sym{[} and \sym{]}.
+\end{itemize}
 \begin{example}[side-by-side]
-  \huge\iupac{2,4\-Di|chlor|pentan} \par
+  \huge\iupac{2,4-Di|chlor|pentan} \par
   2,4-Dichlorpentan
 \end{example}
 
-The spaces inserted by these commands can be customized.
+The spaces inserted by \sym{-} and \sym{\textbar} can be customized.
 \begin{options}
-  \keyval{hyphen-pre-space}{dim}\Module{iupac}\Default{.01em}
-    Set the space that is inserted before the hyphen set with \cs{-}.
-  \keyval{hyphen-post-space}{dim}\Module{iupac}\Default{-.03em}
-    Set the space that is inserted after the hyphen set with \cs{-}.
-  \keyval{break-space}{dim}\Module{iupac}\Default{.01em}
-    Set the space inserted by \cs{\textbar}.
+  \keyval{hyphen-pre-space}{dim}\Module{nomenclature}\Default{.01em}
+    Set the space that is inserted before the hyphen set with \sym{-}.
+  \keyval{hyphen-post-space}{dim}\Module{nomenclature}\Default{-.03em}
+    Set the space that is inserted after the hyphen set with \sym{-}.
+  \keyval{break-space}{dim}\Module{nomenclature}\Default{.01em}
+    Set the space inserted by \sym{\textbar}.
 \end{options}
 
 The command \cs{iupac} serves another purpose, too, however.  Regardless of
-the setting of the \option{iupac} option all the commands presented in this
-section are always defined \emph{inside} \cs{iupac}.  Quite a number of the
-naming commands have very general names: \cs{meta}, \cs{D}, \cs{E}, \cs{L},
-\cs{R}, \cs{S}, \cs{trans} and so forth\footnote{Please read
-  page~\pageref{desc:one-letter-commands} before you consider using the
+the setting of the \option{iupac} option (see below) all the commands
+presented in this section are always defined \emph{inside} \cs{iupac}.  Quite
+a number of the naming commands have very general names: \cs{meta}, \cs{D},
+\cs{E}, \cs{L}, \cs{R}, \cs{S}, \cs{trans} and so forth\footnote{Please read
+  section~\vref{sec:one-letter-commands} before you consider using the
   one-letter commands}.  This means they either are predefined already (\cs{L}
 \L) or are easily defined by another package or class (the \pkg{cool} package
 defines both \cs{D} and \cs{E}, for example).  In order to give you control
-which commands are defined in which way, there is the package option
-\option{iupac}\label{desc:iupac}.  It has three modes:
+which commands are defined in which way, there is the option \option{iupac}:
+\begin{options}
+  \keychoice{iupac}{auto,restricted,strict}\Module{nomenclature}\Default{auto}
+    Take care of how \ac{iupac} naming commands are defined.
+\end{options}
+It has three modes:
 \begin{itemize}
  \item \keyis{iupac}{auto}: if the commands are \emph{not} defined by any
    package or class you're using they are available generally, otherwise only
@@ -836,7 +1009,7 @@ which commands are defined in which way, there is the package option
    commands can be redefined (but only in the document body).  They will still
    be available inside \cs{iupac} then.
 \end{itemize}
-Table~\ref{tab:iupac_modes} demonstrates the different modes.
+Table~\vref{tab:iupac_modes} demonstrates the different modes.
 
 \begin{table}
   \centering
@@ -847,24 +1020,30 @@ Table~\ref{tab:iupac_modes} demonstrates the different modes.
     \midrule
       \cs{L}                  & \L         & \L         & \iupac{\L} \\
       \cs{iupac}\Marg{\cs{L}} & \iupac{\L} & \iupac{\L} & \iupac{\L} \\
-      \cs{D}                  & \D         & --         & \D \\
+      \cs{D}                  & \D         & ---        & \D \\
       \cs{iupac}\Marg{\cs{D}} & \iupac{\D} & \iupac{\D} & \iupac{\D} \\
     \bottomrule
   \end{tabular}
 \end{table}
 
-\subsubsection{Predefined Commands}
+\subsubsection{Macros Defined (Not Only) For Usage in \cs*{iupac}}
 
-The macros in this section are intended to make the writing of \ac{iupac}
-names more convenient.
+\paragraph{One-letter Macros}\label{sec:one-letter-commands}
+For some of the macros explained in this section one-letter commands are
+defined -- with a \latin{caveat} in mind, though: they are not actively
+recommended.  One-letter commands seldomly have meaningful names and often
+they've also been defined by other packages.  This means they make
+collaboration more difficult than it needs to be and are a source for package
+conflicts.  \chemmacros\ solves the latter problem by only providing them
+inside the argument of \cs{iupac}.  The one exception \chemmacros\ makes is
+the command \cs{p} (for things like \pH) which is and will remain an official
+command (see section~\vref{sec:acid-base-module}).  For all other one-letter
+macros alternatives with more meaningful names exist.
 
 \paragraph{Greek Letters}\label{par:greek_letters}
 
-Greek\changedversion{4.3} letters in compound names are typeset upright. For
-this there are for example the packages \pkg{upgreek} and \pkg{textgreek}.  If
-you have loaded one of them\footnote{There are other options, see the
-  description of the \option{greek} option.} the following commands typeset
-upright Greek letters:
+Greek letters in compound names are typeset upright.  Here are a few examples
+for the existing macros:
 \begin{commands}
   \command{chemalpha}[\quad\chemalpha]
     Upright lowercase alpha
@@ -875,15 +1054,15 @@ upright Greek letters:
   \command{chemdelta}[\quad\chemdelta]
     Upright lowercase alpha
 \end{commands}
-The exist two commands for each of the twenty-four Greek letters: a lowercase
-and an uppercase version (\cs{chemalpha} and \cs{chemAlpha}).  Those commands
-are actually provided by the \chemgreek\ package.  For more details refer to
-its documentation.
+There exist two commands for each of the twenty-four Greek letters: a
+lowercase and an uppercase version (\cs{chemalpha} and \cs{chemAlpha}).  Those
+commands are actually provided by the \chemgreek\ package.  For more details
+read section~\vref{sec:greek-module} and also refer to \chemgreek's
+documentation.
 
 There are a number of one-letter commands that some people may find convenient
-to use which use above mentioned commands to pint Greek letters inside
-\cs{iupac}.  They're listed in table~\ref{tab:iupac-greek-shortcuts}.  But
-please read page~\pageref{desc:one-letter-commands} first before you use them.
+to use which use above mentioned commands to print Greek letters inside
+\cs{iupac}.  They're listed in table~\vref{tab:iupac-greek-shortcuts}.
 
 \begin{table}
   \centering
@@ -902,46 +1081,35 @@ please read page~\pageref{desc:one-letter-commands} first before you use them.
   \end{tabular}
 \end{table}
 
-
 \begin{example}
-  \iupac{5\chemalpha\-androstan\-3\chembeta\-ol} \par
-  \iupac{\chemalpha\-(tri|chloro|methyl)\-\chemomega
-    \-chloro|poly(1,4\-phenylene|methylene)}
+  \iupac{5\chemalpha-androstan-3\chembeta-ol} \par
+  \iupac{\chemalpha-(tri|chloro|methyl)-\chemomega
+    -chloro|poly(1,4-phenylene|methylene)}
 \end{example}
 
 \paragraph{Hetero Atoms and added Hydrogen}
 
-Attachments to hetero atoms\changedversion{4.3} and added hydrogen atoms are
-indicated by italic letters~\cite{iupac:greenbook}.  \chemmacros\ defines a
-few macros for the most common ones.
+Attachments to hetero atoms and added hydrogen atoms are indicated by italic
+letters~\cite{iupac:greenbook}.  \chemmacros\ defines a few macros for the
+most common ones.
 \begin{commands}
   \command{hydrogen}[\quad\iupac{\hydrogen}]
-    The italic H for hydrogen.  (An alias for this command is \cs{H}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    The italic H for hydrogen.  (An alias for this command is \cs{H}.)
   \command{oxygen}[\quad\iupac{\oxygen}]
-    The italic O for oxygen.  (An alias for this command is \cs{O}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    The italic O for oxygen.  (An alias for this command is \cs{O}.)
   \command{nitrogen}[\quad\iupac{\nitrogen}]
-    The italic N for nitrogen.  (An alias for this command is \cs{N}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    The italic N for nitrogen.  (An alias for this command is \cs{N}.)
   \command{sulfur}[\quad\iupac{\sulfur}]
-    The italic S for sulfur.  (An alias for this command is \cs{Sf}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    The italic S for sulfur.  (An alias for this command is \cs{Sf}.)
   \command{phosphorus}[\quad\iupac{\phosphorus}]
-    The italic P for phosphorus.  (An alias for this command is \cs{P}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    The italic P for phosphorus.  (An alias for this command is \cs{P}.)
 \end{commands}
 \begin{example}[side-by-side]
-  \iupac{\nitrogen\-methyl|benz|amide}
+  \iupac{\nitrogen-methyl|benz|amide}
   
-  \iupac{3\hydrogen\-pyrrole}
+  \iupac{3\hydrogen-pyrrole}
   
-  \iupac{\oxygen\-ethyl hexanethioate}
+  \iupac{\oxygen-ethyl hexanethioate}
 \end{example}
 
 \paragraph{Cahn-Ingold-Prelog}\label{par:cip}
@@ -949,63 +1117,50 @@ few macros for the most common ones.
   \command{cip}[\marg{conf}]
     Typeset Cahn-Ingol-Prelog descriptors, \eg: \cs{cip}\Marg{R,S} \cip{R,S}
   \command{rectus}[\quad\iupac{\rectus}]
-    Typeset rectus descriptor.  (An alias for this command is \cs{R}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    Typeset rectus descriptor.  (An alias for this command is \cs{R}.)
   \command{sinister}[\quad\iupac{\sinister}]
-    Typeset sinister descriptor.  (An alias for this command is \cs{S}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    Typeset sinister descriptor.  (An alias for this command is \cs{S}.)
 \end{commands}
 
 Both these commands and the entgegen/zusammen descriptors get a small
 additional amount of kerning after the closing parenthesis.  This amount can
 be changed through the following option:
 \begin{options}
-  \keyval{cip-kern}{dim}\Module{iupac}\Default{.075em}
+  \keyval{cip-kern}{dim}\Module{nomenclature}\Default{.075em}
     Set the amount of kerning after the closing parenthesis.
 \end{options}
 
 \paragraph{Fischer}
 \begin{commands}
   \command{dexter}[\quad\iupac{\dexter}]
-    Typeset dexter descriptor.  (An alias for this command is \cs{D}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    Typeset dexter descriptor.  (An alias for this command is \cs{D}.)
   \command{laevus}[\quad\iupac{\laevus}]
-    Typeset laevus descriptor.  (An alias for this command is \cs{L}.  But
-    please read page~\pageref{desc:one-letter-commands} first before you use
-    it.)
+    Typeset laevus descriptor.  (An alias for this command is \cs{L}.)
 \end{commands}
 
 \paragraph{cis/trans, zusammen/entgegen, syn/anti \& tert}
 \begin{itemize}
-  \item[]
-    \cs{cis}   \iupac{\cis} \quad
-    \cs{trans} \iupac{\trans} \quad
-    \cs{fac}   \iupac{\fac} \quad
-    \cs{mer}   \iupac{\mer} \quad
-    \cs{zusammen} \iupac{\zusammen} \quad
-    \cs{entgegen} \iupac{\entgegen} \quad
-    \cs{syn}   \iupac{\syn} \quad
-    \cs{anti}  \iupac{\anti} \quad
-    \cs{tert}  \iupac{\tert}
+  \item \cs{cis}   \iupac{\cis} \quad \cs{trans} \iupac{\trans}
+  \item \cs{fac}   \iupac{\fac} \quad \cs{mer}   \iupac{\mer}
+  \item \cs{sin}   \iupac{\sin} \quad \cs{ter}   \iupac{\ter}
+  \item \cs{zusammen} \iupac{\zusammen} \quad \cs{entgegen} \iupac{\entgegen}
+  \item \cs{syn}   \iupac{\syn} \quad \cs{anti}  \iupac{\anti}
+  \item \cs{tert}  \iupac{\tert}
 \end{itemize}
 An alias for \cs{entgegen} is \cs{E} and an alias for \cs{zusammen} is
-\cs{Z}.  But please read page~\pageref{desc:one-letter-commands} first before
-you use them.
+\cs{Z}.
 
 \paragraph{ortho/meta/para}
-\begin{itemize}
-  \item[]
+\begin{center}
     \cs{ortho} \iupac{\ortho} \quad
     \cs{meta}  \iupac{\meta} \quad
     \cs{para}  \iupac{\para}
-\end{itemize}
+\end{center}
 
-Although these commands are provided I like to cite~\cite{iupac:bluebook}:
+Although these commands are provided I like to cite
+\citetitle{iupac:bluebook}~\cite{iupac:bluebook}:
 
-\begin{cnltxquote}[{\acs{iupac} Blue Book {\cite[][p.\,90]{iupac:bluebook}}}]
+\begin{cnltxquote}[{\cite[][p.\,90]{iupac:bluebook}}]
   The letters \iupac{\ortho}, \iupac{\meta}, and \iupac{\para} have been used
   in place of \textit{ortho}, \textit{meta}, and \textit{para}, respectively,
   to designate the 1,2-, 1,3-, and 1,4- isomers of disubstituted benzene.
@@ -1013,7 +1168,7 @@ Although these commands are provided I like to cite~\cite{iupac:bluebook}:
   names.
 \end{cnltxquote}
 
-\paragraph{Absolute Configuration} (uses \TikZ)
+\paragraph{Absolute Configuration}
 \begin{commands}
   \command{Rconf}[\oarg{letter}]
     \cs{Rconf}: \Rconf \quad \cs{Rconf}\oarg{}: \Rconf[]
@@ -1021,59 +1176,66 @@ Although these commands are provided I like to cite~\cite{iupac:bluebook}:
     \cs{Sconf}: \Sconf \quad \cs{Sconf}\oarg{}: \Sconf[]
 \end{commands}
 
-Examples:\nopagebreak
-\begin{example}
-  \iupac{\dexter\-Wein|s\"aure} =
-  \iupac{\cip{2S,3S}\-Wein|s\"aure} \par
-  \iupac{\dexter\-($-$)\-Threose} =
-  \iupac{\cip{2S,3R}\-($-$)\-2,3,4\-Tri|hydroxy|butanal} \par
-  \iupac{\cis\-2\-Butene} =
-  \iupac{\zusammen\-2\-Butene}, \par
-  \iupac{\cip{2E,4Z}\-Hexa|diene} \par
-  \iupac{\meta\-Xylol} =
-  \iupac{1,3\-Di|methyl|benzene}
-\end{example}
-
 \paragraph{Coordination Chemistry}
 
-\chemmacros\ provides a few commands useful with coordination chemistry:
+\chemmacros\ provides a few commands useful in coordination chemistry:
 \begin{commands}
   \command{bridge}[\marg{num}\quad\bridge{3}]
     Denote bridging ligand connection.
   \command{hapto}[\marg{num}\quad\hapto{5}]
     Denote hapticity.
   \command{dento}[\marg{num}\quad\dento{2}]
-    \sinceversion{4.3}Denote denticity.
+    Denote denticity.
 \end{commands}
 \begin{example}
   Ferrocene = \iupac{bis(\hapto{5}cyclo|penta|dienyl)iron} \par
-  \iupac{tetra\-\bridge{3}iodido\-tetrakis[tri|methyl|platinum(IV)]}
+  \iupac{tetra-\bridge{3}iodido-tetrakis[tri|methyl|platinum(IV)]}
 \end{example}
 
 Two options allow customization:
 \begin{options}
-  \keychoice{bridge-number}{sub,super}\Module{iupac}\Default{sub}
-    Appends the number as a subscript or superscript.  \ac{iupac}
-    recommendation is the subscript~\cite{iupac:redbook}.
-  \keybool{coord-use-hyphen}\Module{iupac}\Default{true}
+  \keychoice{bridge-number}{sub,super}\Module{nomenclature}\Default{sub}
+    Appends the number as a subscript or superscript, depending on the choice.
+    The \ac{iupac} recommendation is the subscript~\cite{iupac:redbook}.
+  \keybool{coord-use-hyphen}\Module{nomenclature}\Default{true}
     Append a hyphen to \cs{hapto}, \cs{dent} and \cs{bridge} or don't.
 \end{options}
 
-\subsubsection{Own Naming Commands}
+\pagebreak
+
+\paragraph{Examples}
+\begin{example}
+  \iupac{\dexter-Wein|s\"aure} =
+  \iupac{\cip{2S,3S}-Wein|s\"aure} \par
+  \iupac{\dexter-($-$)-Threose} =
+  \iupac{\cip{2S,3R}-($-$)-2,3,4-Tri|hydroxy|butanal} \par
+  \iupac{\cis-2-Butene} =
+  \iupac{\zusammen-2-Butene}, \par
+  \iupac{\cip{2E,4Z}-Hexa|diene} \par
+  \iupac{\meta-Xylol} =
+  \iupac{1,3-Di|methyl|benzene}
+\end{example}
+
+\subsubsection{Own \cs*{iupac} Macros And Shorthands}
 
 If you find any commands missing you can define them using
 \begin{commands}
   \command{NewChemIUPAC}[\marg{cs}\marg{declaration}]
-    \sinceversion{4.3}Define a new \ac{iupac} command that is in any case
-    defined inside of \cs{iupac} regardless if \meta{cs} is defined elsewhere
-    already.
+    Define a new \ac{iupac} command that is in any case defined inside of
+    \cs{iupac} regardless if \meta{cs} is defined elsewhere already.
+  \command{ProvideChemIUPAC}[\marg{cs}\marg{declaration}]
+    Define a new \ac{iupac} command that is in any case defined inside of
+    \cs{iupac} regardless if \meta{cs} is defined elsewhere already only if
+    the corresponding \ac{iupac} macro is not defined, yet.
   \command{RenewChemIUPAC}[\marg{cs}\marg{declaration}]
     Redefine an existing \ac{iupac} command that is in any case defined inside
     of \cs{iupac} regardless if \meta{cs} is defined elsewhere already.
   \command{DeclareChemIUPAC}[\marg{cs}\marg{declaration}]
-    \changedversion{4.3}Define a new \ac{iupac} command that is in any case
-    defined inside of \cs{iupac} regardless if \meta{cs} is defined elsewhere
-    already.  This silently overwrites an existing \ac{iupac} definition.
+    Define a new \ac{iupac} command that is in any case defined inside of
+    \cs{iupac} regardless if \meta{cs} is defined elsewhere already.  This
+    silently overwrites an existing \ac{iupac} macro definition.
+  \command{LetChemIUPAC}[\marg{cs1}\marg{cs2}]
+    Defines \meta{cs1} to be an alias of \meta{cs2}.
 \end{commands}
 A command defined in this way will obey the setting of the option
 \option{iupac}.  This means any existing command is only overwritten with
@@ -1082,45 +1244,65 @@ definition of an existing \ac{iupac} naming command but issue an error if the
 \ac{iupac} naming command already exists.  \cs{DeclareChemIUPAC} \emph{will}
 overwrite an existing \ac{iupac} command.
 \begin{example}
-  \NewChemIUPAC\endo{\textit{endo}}
-  \RenewChemIUPAC\anti{\textit{anti}}
-  \iupac{(2\-\endo,7\-\anti)\-2\-bromo\-7\-fluoro|bicyclo[2.2.1]heptane}
+  \NewChemIUPAC\endo{\textsc{endo}}
+  \RenewChemIUPAC\anti{\textsc{anti}}
+  \iupac{(2-\endo,7-\anti)-2-bromo-7-fluoro|bicyclo[2.2.1]heptane}
 \end{example}
 
 \cs{RenewChemIUPAC} allows you to redefine the existing \ac{iupac} naming
 commands.
 \begin{example}[side-by-side]
-  \iupac{\meta\-Xylol} \par
+  \iupac{\meta-Xylol} \par
   \RenewChemIUPAC\meta{\textup{m}}
-  \iupac{\meta\-Xylol}
+  \iupac{\meta-Xylol}
 \end{example}
 
-\subsection{Latin Phrases}
+There's also a way for defining new \ac{iupac} shorthands or changing the
+existing ones:
+\begin{commands}
+  \command{NewChemIUPACShorthand}[\meta{shorthand token}\meta{control sequence}]
+    Defines a new \ac{iupac} shorthand.  Inside \cs{iupac} it will be equal to
+    using \meta{control sequence}.  This throws an error if \meta{shorthand
+      token} is already defined.
+  \command{RenewChemIUPACShorthand}[\meta{shorthand token}\meta{control sequence}]
+    Redefines an existing \ac{iupac} shorthand.  This throws an error if
+    \meta{shorthand token} is not defined, yet.
+  \command{DeclareChemIUPACShorthand}[\meta{shorthand token}\meta{control sequence}]
+    Defines a new \ac{iupac} shorthand or redefines an existing one.
+  \command{ProvideChemIUPACShorthand}[\meta{shorthand token}\meta{control sequence}]
+    Provides a new \ac{iupac} shorthand.  Does nothing if \meta{shorthand
+      token} is already defined.
+  \command{RemoveChemIUPACShorthand}[\meta{shorthand token}]
+    Deletes an existing \ac{iupac} shorthand.
+\end{commands}
 
-The package \pkg{chemstyle} provides the command \cs{latin} to typeset common
-latin phrases in a consistent way.  \chemmacros\ defines a similar \cs{latin}
-only if \pkg{chemstyle} has \emph{not} been loaded and additionally provides
-these commands:
-\begin{itemize}
-  \item[]
-    \cs{insitu}   \insitu \quad
-    \cs{abinitio} \abinitio \quad
-    \cs{invacuo}  \invacuo
-\end{itemize}
+\subsubsection{Latin Phrases}
+
+The package \pkg{chemstyle}~\cite{pkg:chemstyle} provides the command
+\cs{latin} to typeset common latin phrases in a consistent way.  \chemmacros\
+defines a similar \cs{latin} only if \pkg{chemstyle} has \emph{not} been
+loaded and additionally provides these commands:
+\begin{center}
+  \cs{insitu}   \insitu \quad
+  \cs{abinitio} \abinitio \quad
+  \cs{invacuo}  \invacuo
+\end{center}
 
-If the package \pkg{chemstyle} has been loaded they are defined using
+\emph{If the package \pkg{chemstyle} has been loaded they are defined using
 \pkg{chemstyle}'s \cs{latin} command.  This means that then the appearance
-depends on \pkg{chemstyle}'s option \code{abbremph}.
+depends on \pkg{chemstyle}'s option \code{abbremph}.}
 
 The commands are defined through
 \begin{commands}
   \command{NewChemLatin}[\marg{cs}\marg{phrase}]
-    \sinceversion{4.3}Define a new latin phrase. Gives an error if \meta{cs}
-    already exists.
+    Define a new latin phrase.  Gives an error if \meta{cs} already exists.
   \command{DeclareChemLatin}[\marg{cs}\marg{phrase}]
-    \changedversion{4.3}Define a new latin phrase.
+    Define a new latin phrase.  Silently redefined existing macros.
   \command{RenewChemLatin}[\marg{cs}\marg{phrase}]
-    Redefine an existing latin phrase.
+    Redefine an existing latin phrase.  Gives an error if \meta{cs} doesn't
+    exist.
+  \command{ProvideChemLatin}[\marg{cs}\marg{phrase}]
+    Define a new latin phrase only if \meta{cs} doesn't exist.
 \end{commands}
 \begin{example}[side-by-side]
   \NewChemLatin\ltn{latin text}\ltn
@@ -1128,252 +1310,504 @@ The commands are defined through
 If you have \emph{not} loaded \pkg{chemstyle} you can change the appearance
 with this option:
 \begin{options}
-  \keyval{format}{definition}\Module{latin}\Default{\cs*{itshape}}
+  \keyval{format}{definition}\Module{nomenclature}\Default{\cs*{itshape}}
     Set the format of the latin phrases.
 \end{options}
 
-\section{Units for the Usage With \pkg*{siunitx}}\label{sec:einheiten}
+\subsection{The \chemmodule*{particles} Module}\label{sec:particles-module}
 
-In chemistry some non-SI units are very common.  \pkg{siunitx} provides the
-command \cs*{DeclareSIUnit}\marg{command}\marg{unit} to add arbitrary units.
-\chemmacros\ uses that command to provide some units.  Like all \pkg{siunitx}
-units they're only valid inside \cs*{SI}\marg{num}\marg{unit} and
-\cs*{si}\marg{unit}.
-\begin{commands}
-  \command{atmosphere} \si{\atmosphere}
-  \command{atm} \si{\atm}
-  \command{calory} \si{\calory}
-  \command{cal} \si{\cal}
-  \command{cmc} \si{\cmc} \par
-    The units \cs{cmc}, \cs{molar}, and \cs{Molar} are defined by the
-    package \pkg{chemstyle} as well.  \chemmacros\ only defines them, if
-    \pkg{chemstyle} is not loaded.
-  \command{molar} \si{\molar}
-  \command{moLar} \si{\moLar}
-  \command{Molar} \si{\Molar}
-  \command{MolMass} \si{\MolMass}
-  \command{normal} \si{\normal}
-  \command{torr} \si{\torr}
-\end{commands}
+The \chemmodule{particles} module loads the modules \chemmodule{charges} and
+\chemmodule{chemformula}.
+
+\subsubsection{Provided Particle Macros}
+The \chemmodule{particles} defines a number of macros which can be used for
+typesetting common particles in the running text.  Most of them don't make
+much sense in \pkg{chemformula}~\cite{pkg:chemformula}'s \cs{ch}, though,
+which doesn't mean that they can't be used there, of course:
+\begin{center}
+  \cs{el} \el\ \cs{prt} \prt\ \cs{ntr} \ntr\ \cs{Hyd} \Hyd\ \cs{Oxo} \Oxo\
+  \cs{water} \water\ \cs{El} \El\ \cs{Nuc} \Nuc\ \cs{ba} \ba
+\end{center}
+All of these macros are defined using \pkg{chemformula}'s \cs{chcpd}.  The
+details are explained in section~\vref{sec:defin-own-part}.
+
+The macros \cs{Nuc} and \cs{ba} are special:  they have an optional argument
+for the following option:
+\begin{options}
+  \keychoice{elpair}{dots,dash,false}\Module{particles}\Default{false}
+    Determine how the electron pair of the nucleophiles is displayed.  The
+    electron pair is drawn using \chemformula's \cs{chlewis} macro.
+\end{options}
 
-By the way: \cs*{mmHg} \si{\mmHg} already is defined by \pkg{siunitx} and
-\pkg{chemstyle}.
+\begin{example}[side-by-side]
+  \ba[elpair=dots] \Nuc[elpair=dash]
+ 
+  \chemsetup[particles]{elpair=false}
+  \ba\ \Nuc
+\end{example}
 
-\section{Acid/Base}\label{sec:saeure_base}
+\subsubsection{Defining Own Particle Macros}\label{sec:defin-own-part}
 
-Easy representation of \pH, \pKa \ldots\ (the command \cs{pKa} depends on the
-package option \option{language}). The translations may be adapted, though,
-see section~\ref{sec:languages}.
+There are two sets of macros, one for defining particles and one for defining
+nucleophiles.
 \begin{commands}
-  \command{pH} \pH
-  \command{pOH} \pOH
-  \command{Ka} \Ka
-  \command{Kb} \Kb
-  \command{Kw} \Kw
-  \command{pKa}[\oarg{num}] \cs{pKa}: \pKa, \cs{pKa}\Oarg{1}: \pKa[1]
-  \command{pKb}[\oarg{num}] \cs{pKb}: \pKb, \cs{pKb}\Oarg{1}: \pKb[1]
-  \command{p}[\marg{anything}] \eg\ \cs{p}\Marg{\cs{Kw}} \p{\Kw}
+  \command{NewChemParticle}[\marg{cs}\marg{formula}]
+    Defines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Raises an error if \meta{cs} already exists.
+  \command{RenewChemParticle}[\marg{cs}\marg{formula}]
+    Redefines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Raises an error if \meta{cs} doesn't exist.
+  \command{DeclareChemParticle}[\marg{cs}\marg{formula}]
+    Defines a macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Silently overwrites \meta{cs} if it exists.
+  \command{ProvideChemParticle}[\marg{cs}\marg{formula}]
+    Defines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Does nothing if \meta{cs} already exists.
 \end{commands}
+An example of usage is the definition of the existing particle macros:
+\begin{sourcecode}
+  \NewChemParticle\el {e-}
+  \NewChemParticle\prt{p+}
+  \NewChemParticle\ntr{n^0}
+\end{sourcecode}
 
-\begin{example}[side-by-side]
-  \Ka \Kb \pKa \pKa[1] \pKb \pKb[1]
+The following set defines macros like \cs{Nuc}
+\begin{commands}
+  \command{NewChemNucleophile}[\marg{cs}\marg{formula}]
+    Defines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound. Note that \meta{formula} will get a trailing negative charge!
+    Raises an error if \meta{cs} already exists.
+  \command{RenewChemNucleophile}[\marg{cs}\marg{formula}]
+    Redefines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Note that \meta{formula} will get a trailing negative charge!
+    Raises an error if \meta{cs} doesn't exist.
+  \command{DeclareChemNucleophile}[\marg{cs}\marg{formula}]
+    Defines a macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Note that \meta{formula} will get a trailing negative charge!
+    Silently overwrites \meta{cs} if it exists.
+  \command{ProvideChemNucleophile}[\marg{cs}\marg{formula}]
+    Defines a new macro \meta{cs}. \meta{formula} is any valid \chemformula\
+    compound.  Note that \meta{formula} will get a trailing negative charge!
+    Does nothing if \meta{cs} already exists.
+\end{commands}
+An example of usage is the definition of the existing nucleophile macros:
+\begin{sourcecode}
+  \NewChemNucleophile\Nuc{Nu}
+  \NewChemNucleophile\ba {ba}
+\end{sourcecode}
+A macro defined this way will have an optional argument for the
+\option{elpair} option.
+
+\subsection{The \chemmodule*{phases} Module}\label{sec:phases-module}
+
+The \chemmodule{phases} module loads the \chemmodule{chemformula} modul.
+
+\subsubsection{Basics}
+
+These commands are intended to indicate the phase of a compound.
+\begin{center}
+  \cs{sld} \sld \quad \cs{lqd} \lqd \quad \cs{gas} \gas \quad \cs{aq} \aq
+\end{center}
+\begin{example}
+  \ch{C\sld{} + 2 H2O\lqd{} -> CO2\gas{} + 2 H2\gas}\par
+  To make it complete: NaCl\aq.
 \end{example}
 
-\begin{cnltxquote}[{\acs{iupac} Green Book {\cite[][p.\,103]{iupac:greenbook}}}]
- The operator \p{} \textelp{} shall be printed in Roman type.
+The \ac{iupac} recommendation to indicate the state of aggregation is to put
+it in parentheses after the compound \cite{iupac:greenbook}.  However, you
+might want to put it as a subscript which is also very common.
+
+\begin{cnltxquote}[{\citetitle{iupac:greenbook}~\cite[][p.\,54]{iupac:greenbook}}]
+  The \textelp{} symbols are used to represent the states of aggregation of
+  chemical species.  The letters are appended to the formula in parentheses
+  and should be printed in Roman (upright) type without a full stop (period).
 \end{cnltxquote}
 
-There is one option which changes the style the \p{} is typeset:
+There are two options to customize the output:
 \begin{options}
-  \keychoice{p-style}{italics,slanted,upright}\Module{acid-base}\Default{upright}
-    Set the style of the \p{} operator.
-  \keyval{K-acid}{text}\Module{acid-base}\Default{\cs*{mathrm}\Marg{a}}
-    The subscript to \cs{Ka} and \cs{pKa}.
-  \keyval{K-base}{text}\Module{acid-base}\Default{\cs*{mathrm}\Marg{b}}
-    The subscript to \cs{Kb} and \cs{pKb}.
-  \keyval{K-water}{text}\Module{acid-base}\Default{\cs*{mathrm}\Marg{w}}
-    The subscript to \cs{Kw}.
-  % \keychoice{subscript}{lowercase,uppercase}\Module{acid-base}\Default{uppercase}
-  %   Choose\sinceversion{4.5} if the default subscript is written in lower- or
-  %   uppercase.
+  \keychoice{pos}{side,sub}\Module{phases}\Default{side}
+    Switch the position of the phase indicator.
+  \keyval{space}{dim}\Module{phases}\Default{.1333em}
+    Change the default spacing between compound a phase indicator if
+    \keyis{pos}{side}. A \TeX\ dimension.
 \end{options}
 \begin{example}
-  \pH, \pKa \par
-  \chemsetup[acid-base]{p-style=slanted} \pH, \pKa \par
-  \chemsetup[acid-base]{p-style=italics} \pH, \pKa
+  \chemsetup[phases]{pos=sub}
+  \ch{C\sld{} + 2 H2O\lqd{} -> CO2\gas{} + 2 H2\gas}\par
+  To make it complete: NaCl\aq.
 \end{example}
 
-As\changedversion{4.7} you can see the default subscripts of \cs{Kw}, \cs{Ka}
-and \cs{Kb} are lowercase letters.  The literature is inconclusive about if
-this is the right way or if uppercase letters should be preferred.  In
-textbooks the uppercase variant usually seems to be used while journals seem
-to prefer the lowercase variant.  \chemmacros' default follows the usage
-in~\cite{iupac:greenbook}.  If you want to change this you have two
-possibilities:
+All those phase commands have an optional argument:
+\begin{example}[side-by-side]
+  \ch{H2O "\lqd[\SI{5}{\celsius}]"}
+\end{example}
+
+There is also a generic phase command:
+\begin{commands}
+  \command{phase}[\marg{phase}]
+    If you need a phase indicator just once or twice.  You can use it to
+    denote a phase for which there is no phase command, yet.
+\end{commands}
+
+\subsubsection{Define Own Phases}
+Depending on the subject of your document you might need to indicate other
+states of aggregation.  You can easily define them.
+\begin{commands}
+  \command{NewChemPhase}[\marg{cs}\marg{symbol}]
+    Define a new phase command.  See section~\vref{sec:lang-depend} for a way
+    to define language dependent settings.  Gives an error if \meta{cs}
+    already exists.
+  \command{DeclareChemPhase}[\marg{cs}\marg{symbol}]
+    Define a new phase command. See section~\vref{sec:lang-depend} for a way to
+    define language dependent settings.  Overwrites previous definitions of
+    \meta{cs}.
+  \command{RenewChemPhase}[\marg{cs}\marg{symbol}]
+    Redefine an existing phase command.  See section~\vref{sec:lang-depend} for
+    a way to define language dependent settings.  Gives an error if \meta{cs}
+    is not defined.
+  \command{ProvideChemPhase}[\marg{cs}\marg{symbol}]
+    Define a new phase command.  See section~\vref{sec:lang-depend} for a way
+    to define language dependent settings.  Does nothing if \meta{cs} is
+    already defined.
+\end{commands}
 
 \begin{example}
-  % this works only in the preamble:
-  % \DeclareTranslation{English}{K-acid}{\mathrm{A}}% use your language here
-  % alternative:
-  \chemsetup{acid-base/K-acid=\mathrm{A}}% overwrites language dependent settings
-  \pKa
+  % preamble:
+  \NewChemPhase\aqi{aq,$\infty$} % aqueous solution at infinite dilution
+  \NewChemPhase\cd {cd} % condensed phase
+  \NewChemPhase\lc {lc} % liquid crystal
+  \ch{NaOH\aqi} \ch{H2O\cd} \ch{U\phase{cr}} \ch{A\lc}\par
+  \chemsetup[phases]{pos=sub}
+  \ch{NaOH\aqi} \ch{H2O\cd} \ch{U\phase{cr}} \ch{A\lc}
 \end{example}
 
-\section{Oxidation Numbers, Real and Formal Charges}\label{sec:ladungen}
+\subsubsection{Language Dependencies}\label{sec:lang-depend}
+For each phase command a translation into the custom language can be defined.
+If a phase is declared with \cs{NewChemPhase} no translation exists and
+for every \pkg{babel} language the literal string is used that was provided
+as a definition.  Let's say you define the phase
+\begin{sourcecode}
+  \NewChemPhase\liquid{l}
+\end{sourcecode}
+and want to add the German translation ``f\/l''.  Then you could do
+\begin{sourcecode}
+  \DeclareTranslation{German}{phase-liquid}{f\/l}
+\end{sourcecode}
+This way, when you use it in a German document using the appropriate
+\pkg{babel} option using \cs*{liquid} would correctly translate.  For this the
+package \pkg{translations}~\cite{pkg:translations} is used.  The \acs{id}
+always is \code{phase-\meta{csname}} where \meta{csname} is the name of the
+phase command you defined without leading backslash.
 
-\chemmacros{} distinguishes between real ($+$/$-$) and formal (\fplus/\fminus)
-charge symbols, also see section~\ref{sec:options}.  All commands using formal
-charge symbols start with a \code{f}.
+See section~\vref{sec:lang-module} for predefined translations and general
+language options of \chemmacros.
 
-\subsection{Ion Charges}\label{ssec:ionen}
+\subsection{The \chemmodule*{symbols} Module}\label{sec:symbols-module}
 
-Simple displaying of (real) charges.  It is worth noting that these commands
-really are relicts from a time when \chemmacros\ tried hard to be compliant
-with \pkg{mhchem} and \chemformula\ didn't exist, yet.  They are still provided
-for backwards compatibility but \emph{my recommendation is to use} \cs{ch}
-(see the documentation of the \chemformula\ package) \emph{and forget about
-  these commands:}
+The \chemmodule{symbols} module defines a few symbols chemists need now and
+then.  It loads the package \pkg{amstext}~\cite{pkg:amstext}.
 \begin{commands}
-  \command{pch}[\oarg{number}]
-    positive charge (\textbf{p}lus + \textbf{ch}arge)
-  \command{mch}[\oarg{number}]
-    negative charge (\textbf{m}inus + \textbf{ch}arge)
+  \command{transitionstatesymbol}
+    This is self-explaining: \transitionstatesymbol
+  \command{standardstate}
+    Again self-explaining: \standardstate
+  \command{changestate}
+    The uppercase delta used in \state[superscript=]{H} for example.
 \end{commands}
 
-\begin{example}[side-by-side]
-  \leavevmode
-  \pch, Na\pch, Ca\pch[2]\par
-  \leavevmode
-  \mch, F\mch, S\mch[2]
-\end{example}
+\section{Internal Modules}
+\subsection{The \chemmodule*{base} Module}\label{sec:base-module}
+
+The \chemmodule{base} module is the core module of \chemmacros. It defines
+some tools which can (and should) be used in other modules.  This means this
+section is only interesting for you if you plan to write a module yourself
+(see section~\vref{sec:own-modules} for details).
+
+This module requires the packages \pkg{bm}~\cite{pkg:bm} and
+\pkg{amstext}~\cite{pkg:amstext}.
+
+This module also provides \cs{chemsetup} and the option \option{modules}.
 
-The same for formal charges:
+It also provides a number of (expl3) macros which may be used in other
+modules. In the macro descriptions below \TF\ denotes that a \code{T}, an
+\code{F} and a \code{TF} variant exist.  In case of an expandable conditional
+(\expandablesymbol) also the predicate variant is available.
 \begin{commands}
-  \command{fpch}[\oarg{number}]
-    positive charge
-  \command{fmch}[\oarg{number}]
-    negative charge
+  \expandable\command*{chemmacros_is_int:n}[\TF\ \marg{number} \marg{true}
+  \marg{false}]
+    Checks if \meta{number} is an integer or not.
+  \expandable\command*{chemmacros_if_loaded:nn}[\TF\
+  \Marg{\meta{package}|\meta{class}} \marg{name} \marg{true} \marg{false}]
+    Checks if package (or class) \meta{name} has been loaded. Also works after
+    begin document.
+  \expandable\command*{chemmacros_if_package_loaded:n}[\TF\ \marg{name}
+  \marg{true} \marg{false}]
+    Checks if package \meta{name} has been loaded. Also works after begin
+    document.
+  \expandable\command*{chemmacros_if_class_loaded:n}[\TF\ \marg{name}
+  \marg{true} \marg{false}]
+    Checks if class \meta{name} has been loaded. Also works after begin
+    document.
+  \command*{chemmacros_leave_vmode:}
+    Equivalent of \cs*{leavevmode}.
+  \command*{chemmacros_nobreak:}
+    Inserts a penalty of \num{10000}.
+  \command*{chemmacros_allow_break:}
+    Inserts a penalty of \num{0}.
+  \command*{chemmacros_skip_nobreak:N}[ \meta{skip/length variable}]
+    Insert a horizontal skip while linebreak is disallowed.
+  \command*{chemmacros_if_is_int:n}[\TF\ \marg{input} \marg{true} \marg{false}]
+    Checks if \meta{input} is an integer or something else.
+  \command*{chemmacros_if_bold:}[\TF\ \marg{true} \marg{false}]
+    Checks if the current font weight is one of \chemboldchecks{or}.
+  \command*{chemmacros_bold:n}[ \marg{text}]
+    Checks if the current font weight is bold and if yes places \meta{text} in
+    \cs*{textbf} if in text mode or in \cs*{bm} if in math mode.  If false
+    \meta{text} simply is placed in the input stream as is.
+  \command*{chemmacros_text:n}[ \marg{text}]
+    Ensures that \meta{text} is placed in text mode.
+  \command*{chemmacros_math:n}[ \marg{text}]
+    Ensures that \meta{text} is placed in math mode.
+  \command*{chemmacros_new_macroset:nnn}[ \marg{type} \marg{arg spec}
+  \marg{internal command call}]
+    A command to define a set of macros \cs*{NewChem\meta{type}},
+    \cs*{RenewChem\meta{type}}, \cs*{DeclareChem\meta{type}} and
+    \cs*{ProvideChem\meta{type}}. \meta{arg spec} is any valid argument
+    specification for \pkg{xparse}'s \\
+    \cs{DeclareDocumentCommand}~\cite{bnd:l3packages}. \meta{internal command
+      call} should be a macro which makes definitions \emph{without} error
+    checks, \ie, define new macros or redefine existing ones like \cs*{def}
+    does.  This macro just should get the arguments passed on to.  Have a look
+    at the example below.
 \end{commands}
+This is how the macros \cs{NewChemParticle}, \cs{RenewChemParticle},
+\cs{DeclareChemParticle} and \cs{ProvideChemParticle} were defined:
+\begin{sourcecode}
+  \chemmacros_new_macroset:nnn {Particle} {mm}
+    { \chemmacros_define_particle:Nn #1 {#2} }
+\end{sourcecode}
 
-\begin{example}[side-by-side]
-  \leavevmode
-  \fpch\ \fmch\ \fpch[3] \fmch[3]
-\end{example}
+\subsection{The \chemmodule*{chemformula} Module}\label{sec:chemformula-module}
+
+The \chemmodule{chemformula} module loads the \pkg{chemformula}
+package~\cite{pkg:chemformula} and the \pkg{amstext}
+package~\cite{pkg:amstext}.  It also loads the \chemmodule{charges} module.
 
-\subsection{Oxidation Numbers}\label{ssec:oxidationszahlen}
+\subsubsection{For Users}
+The \chemmodule{chemformula} module makes it possible that you can set all
+\chemformula\ options via the \cs{chemsetup} command using the module
+\module{chemformula}, for example:
+\begin{sourcecode}
+  \chemsetup[chemformula]{format=\sffamily}
+\end{sourcecode}
+
+\subsubsection{For Module Writers}
 
-Typesetting oxidation numbers:
+There's only one macro for module writers:
 \begin{commands}
-  \command{ox}[\oarg{options}\Marg{\meta{number},\meta{atom}}]
-    Places \meta{number} above \meta{atom}; \meta{number} has to be a
-    (rational) number!
+  \command*{chemmacros_chemformula:n}[ \marg{formula}]
+    This is only a wrapper for \cs{chcpd}.  It is recommended that module
+    writers use this macro (or a variant thereof) inside of \chemmacros's
+    macros whenever they want to display a chemical formula.  Writers who
+    prefer traditional \LaTeXe\ programming over expl3 should use \cs{chcpd}
+    directly.
 \end{commands}
 
-\begin{example}
-  \ox{+1,Na}, \ox{2,Ca}, \ox{-2,S}, \ox{-1,F}
-\end{example}
+\subsection{The \chemmodule*{greek} Module}\label{sec:greek-module}
+
+The \chemmodule{greek} module loads the \pkg{chemgreek}
+package~\cite{pkg:chemgreek}.
 
-There are a number of keys, that can be used to modify the \cs{ox} command.
+This module provides one option:
 \begin{options}
-  \keybool{parse}\Module{ox}\Default{true}
-    When \code{false} an arbitrary entry can be used for \code{<number>}.
-  \keybool{roman}\Module{ox}\Default{false}
-    Switches from roman to arabic numbers.
-  \keychoice{pos}{top,super,side}\Module{ox}\Default{top}
-    \code{top} places \meta{number} above \meta{atom}, \code{super} to the
-    upper right as superscript and \code{side} to the right and inside
-    brackets.
-  \keybool{explicit-sign}\Module{ox}\Default{false}
-    Shows the $+$ for positiv numbers and the $\pm$ for $0$.
-  \keychoice{decimal-marker}{comma,point}\Module{ox}\Default{point}
-    Choice for the decimal marker for formal oxidation numbers like \ox{1.2,X}.
-  \keychoice{align}{center,right}\Module{ox}\Default{center}
-    Center the oxidation number relative to the atom or right-align it.
+  \keyval{greek}{mapping}
+    A valid value is any valid \chemgreek\ \meta{mapping}.  \chemmacros\ will
+    warn you if no mapping has been chosen or if you are using the
+    \code{default} or the \code{var-default} mapping because this means that
+    no upright Greek letters are available.
 \end{options}
+If you load a \chemgreek\ support package which allows an unambiguous choice
+of a mapping \chemgreek\ will make this choice automatically.  This means if
+you say
+\begin{sourcecode}
+  \usepackage{upgreek}
+  \usepackage{chemmacros}
+\end{sourcecode}
+then \chemmacros\ will use \pkg{upgreek}'s upright Greek letters.  If you
+have
+\begin{sourcecode}
+  \usepackage{upgreek}
+  \usepackage{chemmacros}
+  \usepackage{textgreek}
+\end{sourcecode}
+then no unambiguous choice is possible and you should choose a mapping
+yourself, for example:
+\begin{sourcecode}
+  \usepackage{upgreek}
+  \usepackage{chemmacros}
+  \usepackage{textgreek}
+  \chemsetup{greek=textgreek}
+\end{sourcecode}
+For further details on mappings please refer to \chemgreek's manual.
 
-\begin{example}[side-by-side]
-  \ox[roman=false]{2,Ca} \ox{2,Ca} \\
-  \ox[pos=super]{3,Fe}-Oxide \\
-  \ox[pos=side]{3,Fe}-Oxide \\
-  \ox[parse=false]{?,Mn} \\
-  \ox[align=right]{2,Ca}
-\end{example}
+\subsection{The \chemmodule*{lang} Module}\label{sec:lang-module}
 
-The \keyis{pos}{super} variant also can be set with the shortcut \cs{ox}\sarg:
-\begin{example}[side-by-side]
-  \ox{3,Fe} \ox*{3,Fe}
-\end{example}
+The \chemmodule{lang} module provides language support for \chemmacros.  It
+loads the package \pkg{translations}~\cite{pkg:translations}.
 
-Using the \option{explicit-sign} key will always show the sign of the
-oxidation number:
-\begin{example}
-  \chemsetup[ox]{explicit-sign = true}
-  \ox{+1,Na}, \ox{2,Ca}, \ox{-2,S}, \ch{"\ox{0,F}" {}2}
-\end{example}
+\subsubsection{Information For Users}
 
-\begin{example}
-  Compare \ox{-1,\ch{O2^2-}} to \ch{"\ox{-1,O}" {}2^2-}
-\end{example}
+This module defines the following option:
+\begin{options}
+  \keychoice{language}{auto,\meta{language}}\Default{auto}
+    If set to \code{auto} \chemmacros\ will detect the language used by
+    \pkg{babel}~\cite{pkg:babel} or \pkg{ployglossia}~\cite{pkg:polyglossia}
+    automatically, fallback is English.  Any language known to the
+    \pkg{translations} package is a valid value for \meta{language}.
+\end{options}
 
-Sometimes one might want to use formal oxidation numbers like \num{.5} or
-$\frac{1}{3}$:
-\begin{example}[side-by-side]
-  \ox{.5,\ch{Br2}} \ch{"\ox{1/3,I}" {}3+}
-\end{example}
+The language chosen via \option{language} is used for translation of certain
+strings in different places all over \chemmacros.  They are mentioned in the
+places when the corresponding function of \chemmacros\ is explained.
 
-The fraction uses the \cs*{sfrac} command of the \pkg{xfrac} package.  For
-this purpose the instance \code{chemmacros-ox-frac} is defined.
-\begin{sourcecode}
-  \DeclareInstance{xfrac}{chemmacros-ox-frac}{text}{
-    scale-factor        = 1.2 ,
-    denominator-bot-sep = -.5ex ,
-    numerator-top-sep   = -.3ex ,
-    slash-left-kern     = -.2em ,
-    slash-right-kern    = -.2em ,
-    slash-symbol-font   = lmr
-  }
-\end{sourcecode}
-Of course you can redefine it so that it suits your needs as the output often
-strongly depends on the used font.
+Translation is done with the help of the \pkg{translations} package, available
+translation keys are listed in section~\vref{sec:avail-transl-keys}.
 
-\subsection{Partial Charges and Similar Stuff}\label{ssec:partialladungen}
+\subsubsection{Available Translation Keys}\label{sec:avail-transl-keys}
 
-The next ones probably are seldomly needed but nevertheless useful:
+Table~\vref{tab:translation-keys} lists (almost) all keys which are predefined
+in \chemmacros.  A translation key is a key which is understood by the
+\pkg{translations} package and its commands like \cs*{GetTranslation}.  For
+each key at least the English fallback translation is provided, for most also
+the German translation is provided.  For a few keys also other translations
+are provided.  If you find that your translation is missing you can provide it
+in the preamble:
 \begin{commands}
-  \command{delp} \delp\ (\textbf{del}ta + \textbf{p}lus)
-  \command{delm} \delm\ (\textbf{del}ta + \textbf{m}inus)
-  \command{fdelp} \fdelp
-  \command{fdelm} \fdelm
+  \command*{DeclareTranslation}[\marg{language}\marg{key}\marg{translation}]
+    Defines a translation of key \meta{key} for the language \meta{language}.
+    No error will be raised if a translation of \meta{key} already exists.
+    This command can only be used in the preamble and is defined by the
+    \pkg{translations} package.
 \end{commands}
+f you send me an email (see section~\vref{sec:sugg-bug-reports}) with the
+translations for your language I'll gladly add them to the next release of
+\chemmacros!
 
-These macros for example can be used with the \cs{ox} command or with the
-\pkg{chemfig} package:
-\begin{example}
-  \chemsetup{
-    option/circled = all,
-    ox/parse       = false
+\begin{table}
+  \centering
+  \caption{Translation keys predefined by \chemmacros.}
+  \label{tab:translation-keys}
+  \NewDocumentCommand\showtranslation{mm}{%
+    \SaveTranslationFor\tmp{#1}{#2}%
+    \code{\detokenize\expandafter{\tmp}}%
   }
-  \ch{"\ox{\delp,H}" -{} "\ox{\delm,Cl}"} \hspace*{1cm}
-  \chemfig{\chemabove[3pt]{\lewis{246,Br}}{\delm}-\chemabove[3pt]{H}{\delp}}
-\end{example}
+  \NewDocumentCommand\showtranslations{m}{
+    \code{#1} &
+    \showtranslation{fallback}{#1} &
+    \showtranslation{german}{#1}
+  }
+ \begin{tabular}{lll}
+    \toprule
+      \bfseries key & \bfseries fallback translation & \bfseries German \\
+    \midrule
+      \showtranslations{scheme-name} \\
+      \showtranslations{scheme-list} \\
+      \showtranslations{K-acid} \\
+      \showtranslations{K-base} \\
+      \showtranslations{K-water} \\
+      \showtranslations{phase-sld} \\
+      \showtranslations{phase-lqd} \\
+      \showtranslations{phase-gas} \\
+      \showtranslations{phase-aq} \\
+      \showtranslations{list-of-reactions} \\
+      \showtranslations{reaction} \\
+    \bottomrule
+  \end{tabular}
+\end{table}
+
+\subsubsection{Information For Module Writers}
 
-The following macros are useful together with \pkg{chemfig}, too.
 \begin{commands}
-  \command{scrp} \scrp\ (\textbf{scr}iptstyle + \textbf{p}lus)
-  \command{scrm} \scrm\ (\textbf{scr}iptstyle + \textbf{m}inus)
-  \command{fscrp} \fscrp
-  \command{fscrm} \fscrm
-  \command{fsscrp} \fsscrp\ (using \cs*{scriptscriptstyle})
-  \command{fsscrm} \fsscrm
+  \expandable\command*{chemmacros_translate:n}[ \marg{translation key}]
+    Translates the given key to the language which is detected automatically
+    or given by the user.  Should be used in \chemmacros's macros instead of
+    \pkg{translations}' \cs*{GetTranslation}.
+  \command*{l_chemmacros_language_tl}
+    A token list variable that holds the language which is used by
+    \cs*{chemmacros_translate:n} for translation, \emph{after begin
+      document}.
+  \command{ChemTranslate}[\marg{translation key}]
+    A version of \cs*{chemmacros_translate:n} for those who prefer
+    traditional \LaTeXe\ programming over expl3.
 \end{commands}
 
-\begin{example}
-  \setatomsep{1.8em}\chemfig{CH_3-\chemabove{C}{\scrp}(-[6]C|H_3)-\vphantom{H_3}CH_3}
-  
-  \chemfig{\fmch{}|O-\chemabove{N}{\fscrp}(-[1]O|\fmch)-[7]O|\fmch}
+\clearpage
+
+\part{Additional Modules}\label{part:additional-modules}
+
+\section{User Modules}
+\subsection{The \chemmodule*{all} \emph{pseudo}-module}\label{sec:all-module}
+
+The \chemmodule{all} module is a pseudo module: it doesn't define any
+functionality at all.  It does however load all other modules.  So you can say
+\begin{sourcecode}
+  \chemsetup{ modules = all }
+\end{sourcecode}
+to ensure that every module is available.  This \emph{will not} load personal
+modules!
+
+\subsection{The \chemmodule*{isotopes} Module}\label{sec:isotopes-module}
+
+The \chemmodule{isotope} module loads the \pkg{elements}
+package~\cite{pkg:elements}.  This module defines one user command:
+\begin{commands}
+  \command{isotope}[\sarg\marg{input}]
+    \meta{input} can either be the \emph{symbol} of an element or the
+    \emph{name} of an element.  Be aware that \emph{the name is language
+      dependent}, refer to the manual of the \pkg{elements} package for
+    details.  To be on the safe side use the element symbol.
+
+    \meta{input} can also be comma separated list:
+    \cs{isotope}\Marg{\meta{nuc},\meta{symbol}}.  If you leave \meta{nuc} out
+    then \cs{isotope} will display the most common isotope.  Otherwise
+    \meta{nuc} will be used.  If \meta{nuc} is an isotope unknown to the
+    \pkg{elements} package \cs{isotope} will write a warning to the log file.
+
+    The starred variant omits the element number.
+\end{commands}
+
+\begin{example}[side-by-side]
+  \isotope{C}
+  \isotope*{C}
+  \isotope{14,C}
+  \isotope*{14,C}
+\end{example}
+
+As input for the element symbol you can choose any of the elements known to
+the \pkg{elements} package.
+
+There are options which allow you to determine how the isotope is printed:
+\begin{options}
+  \keychoice{format}{super,side}\Module{isotopes}\Default{super}
+    Either print the isotope number as superscript or to the right of the
+    element symbol.
+  \keyval{side-connect}{input}\Module{isotopes}\Default{-}
+    Determine what is printed between the element symbol and the isotope
+    number if \keyis{format}{side}.
+\end{options}
+
+\begin{example}[side-by-side]
+  \isotope{C}
+  \chemsetup[isotopes]{format=side}
+  \isotope{C}
+  \chemsetup[isotopes]{side-connect=}
+  \isotope{C}
 \end{example}
 
-\section{Reaction Mechanisms}\label{sec:mechanismen}
+\subsection{The \chemmodule*{mechanisms} Module}\label{sec:mechanisms-module}
+
+The module \chemmodule{mechanisms} loads the package
+\pkg{amstext}~\cite{pkg:amstext}.  It provides one macro:
 
 \begin{commands}
   \command{mech}[\oarg{type}]
@@ -1406,7 +1840,440 @@ The following macros are useful together with \pkg{chemfig}, too.
     \mech[cb]
 \end{commands}
 
-\section{Redox Reactions}\label{sec:redoxreaktionen}% TODO: watch pagebreaks!
+\subsection{The \chemmodule*{newman} Module}\label{sec:newman-module}
+The \chemmodule{newman} module provides a command for drawing Newman
+projections.  It loads the \chemmodule{tikz} module.
+\begin{commands}
+  \command{newman}[\oarg{options}\darg{angle}%
+    \Marg{\meta{1},\meta{2},\meta{3},\meta{4},\meta{5},\meta{6}}]
+    Create Newman projections.  This command uses \TikZ\ internally.
+    \meta{angle} rotates the back atoms counter clockwise with respect to the
+    front atoms and is an optional argument.  \meta{1} to \meta{6} are the
+    positions, the first three are the front atoms, the last three the back
+    atoms.
+\end{commands}
+
+\begin{example}
+  \newman{} \newman(170){}
+  \newman{1,2,3,4,5,6} \newman{1,2,3} \newman{,,,4,5,6}
+\end{example}
+
+Several options allow customization:
+\begin{options}
+  \keyval{angle}{angle}\Module{newman}\Default{0}
+    Default angle.
+  \keyval{scale}{factor}\Module{newman}\Default{1}
+    Scale the whole projection by factor \meta{factor}.
+  \keyval{ring}{tikz}\Module{newman}\Default
+    Customize the ring with \TikZ\ keys.
+  \keyval{atoms}{tikz}\Module{newman}\Default
+    Customize the nodes within which the atoms are set with \TikZ\ keys.
+  \keyval{back-atoms}{tikz}\Module{newman}\Default
+    Explicitly customize the nodes of the back atoms with \TikZ\ keys.
+\end{options}
+
+\begin{example}
+  \chemsetup[newman]{angle=45} \newman{}
+  \newman[scale=.75,ring={draw=blue,fill=blue!20}]{}
+\end{example}
+
+\begin{example}
+  \chemsetup[newman]{atoms={draw=red,fill=red!20,inner sep=2pt,rounded corners}}
+  \newman{1,2,3,4,5,6}
+\end{example}
+
+\begin{example}
+  \chemsetup[newman]{
+    atoms = {draw=red,fill=red!20,inner sep=2pt,rounded corners},
+    back-atoms = {draw=blue,fill=blue!20,inner sep=2pt,rounded corners}
+  }
+  \newman{1,2,3,4,5,6} \newman(170){1,2,3,4,5,6}
+\end{example}
+
+\subsection{The \chemmodule*{orbital} Module}\label{sec:orbital-module}
+The \chemmodule{orbital} module loads the \chemmodule{tikz} module.  It
+provides the following command to create orbitals:
+\begin{commands}
+  \command{orbital}[\oarg{options}\marg{type}]
+    Draw an orbital shape of type \meta{type}.  This command uses \TikZ\
+    internally.
+\end{commands}
+
+There are the following types available for \meta{type}:
+\begin{center}
+  \code{s} \quad
+  \code{p} \quad
+  \code{sp} \quad
+  \code{sp2} \quad
+  \code{sp3}
+\end{center}
+
+\begin{example}
+  \orbital{s} \orbital{p} \orbital{sp} \orbital{sp2} \orbital{sp3}
+\end{example}
+
+Depending on the type you have different options to modify the orbitals:
+\begin{options}
+  \keychoice{phase}{+,-}\Module{orbital}\Default{+}
+    changes the phase of the orbital (all types)
+  \keyval{scale}{factor}\Module{orbital}\Default{1}
+    changes the size of the orbital (all types)
+  \keyval{color}{color}\Module{orbital}\Default{black}
+    changes the color of the orbital (all types)
+  \keyval{angle}{angle}\Module{orbital}\Default{0}
+    rotates the orbitals with a p contribution counter clockwise (all types
+    except \code{s})
+  \keybool{half}\Module{orbital}\Default{false}
+    displays only half an orbital (only \code{p})
+\end{options}
+
+\begin{example}
+  \orbital{s} \orbital[phase=-]{s} 
+  \orbital{p} \orbital[phase=-]{p}
+  \orbital{sp3} \orbital[phase=-]{sp3}
+ 
+  \orbital[angle=0]{p} \orbital[color=red!50]{p}
+  \orbital[angle=135,scale=1.5]{p} \orbital[half]{p}
+\end{example}
+
+Additionally there are two options, with which the \TikZ\ behaviour can be
+changed.
+\begin{options}
+  \keybool{overlay}\Module{orbital}
+    The orbital \enquote{doesn't need space}; it is displayed with the \TikZ\
+    option \code{overlay}.
+  \keyval{opacity}{num}\Module{orbital}
+    The orbital becomes transparent; \meta{value} can have values between
+    \code{1} (fully opaque) to \code{0} (invisible).
+\end{options}
+\begin{example}
+  \vspace{7mm}
+  \chemsetup[orbital]{
+    overlay,
+    p/color = black!70
+  }
+  \setbondoffset{0pt}
+  \chemfig{
+    ?\orbital{p}
+    -[,1.3]{\orbital[phase=-]{p}}
+    -[:30,1.1]\orbital{p}
+    -[:150,.9]{\orbital[phase=-]{p}}
+    -[4,1.3]\orbital{p}
+    -[:-150,1.1]{\orbital[phase=-]{p}}?
+  }
+  \vspace{7mm}
+\end{example}
+
+\begin{example}
+  \vspace{7mm}
+  \setbondoffset{0pt}
+  \chemsetup[orbital]{
+    overlay ,
+    opacity = .75 ,
+    p/scale = 1.6 ,
+    s/color = blue!50 ,
+    s/scale = 1.6
+  }
+  \chemfig{
+    \orbital{s}
+    -[:-20]{\orbital[scale=2]{p}}
+           {\orbital[half,angle=0]{p}}
+           {\orbital[angle=170,half]{p}}
+           {\orbital[angle=-150,half]{p}}
+    (-[:-150]\orbital{s})-\orbital{s}
+  }
+  \vspace{1cm}
+\end{example}
+
+\subsection{The \chemmodule*{reactions} Module}\label{sec:reactions-module}
+The \chemmodule{reactions} module loads the \chemmodule{chemformula} module
+and the \pkg{mathtools} package~\cite{pkg:mathtools}.
+
+\subsubsection{Predefined Environments}
+
+You can use these environments for numbered\ldots
+\begin{environments}
+  \environment{reaction}
+    A single reaction where \chemformula\ code is placed directly in the
+    environment body.  A wrapper around the \env*{equation} environment.
+  \environment{reactions}
+    Several aligned reactions.  A wrapper around \pkg{amsmath}'s \env*{align}
+    environment.
+\end{environments}
+
+\ldots and their starred versions for unnumbered reactions.
+\begin{environments}
+  \environment{reaction*}
+    A wrapper around the \env*{equation*} environment.
+  \environment{reactions*}
+    A wrapper around \pkg{amsmath}'s \env*{align*} environment.
+\end{environments}
+
+With them you can create (un)numbered reaction equations similar to
+mathematical equations.
+
+Theses environments use the \env*{equation}/\env*{equation*} environments or
+the \env*{align}/\env*{align*} environments, respectively, to display the
+reactions.
+
+\begin{example}
+  Reaction with counter:
+  \begin{reaction}
+    A -> B
+  \end{reaction}
+\end{example}
+
+\begin{example}
+  Reaction without counter:
+  \begin{reaction*}
+    C -> D
+  \end{reaction*}
+\end{example}
+
+\begin{example}
+  Several aligned reactions with counter:
+  \begin{reactions}
+    A     &-> B + C \\
+    D + E &-> F
+  \end{reactions}
+\end{example}
+
+\begin{example}
+  Several aligned reactions without counter:
+  \begin{reactions*}
+    G     &-> H + I \\
+    J + K &-> L
+  \end{reactions*}
+\end{example}
+
+If you want to change the layout of the counter tags, you can use
+
+\begin{commands}
+  \command*{renewtagform}[\marg{tagname}\oarg{format}\marg{right delimiter}\marg{left
+  delimiter}]
+    Provided by the \pkg{mathtools} package.
+\end{commands}
+
+\begin{example}
+  \renewtagform{reaction}[R \textbf]{[}{]}
+  \begin{reaction}
+    H2O + CO2 <<=> H2CO3
+  \end{reaction}
+\end{example}
+
+The use of \AmS math's \cs{intertext} is possible:
+\begin{example}
+  \begin{reactions}
+    A + 2 B &-> 3 C + D "\label{rxn:test}"
+    \intertext{Some text in between aligned reactions}
+    3 E + F &<=> G + 1/2 H
+  \end{reactions}
+  See reaction~\ref{rxn:test}.
+\end{example}
+
+% \emph{You should not use \cs{mch} and its relatives inside the \env{reaction}
+%   environments.}
+
+\subsubsection{Own Reactions}
+You can create new types of reactions with the command:
+\begin{commands}
+  \command{NewChemReaction}[\marg{name}\oarg{number of arguments}\marg{math name}]
+    \meta{name} will be the name of the new chem environment. \meta{math name} is
+    the underlying math environment.  Gives an error if \meta{name} already
+    exists.
+  \command{RenewChemReaction}[\marg{name}\oarg{number of arguments}\marg{math name}]
+    \meta{name} is the name of the renewed chem environment. \meta{math name} is
+    the underlying math environment.  Gives an error if \meta{name} does not exist.
+  \command{DeclareChemReaction}[\marg{name}\oarg{number of arguments}\marg{math name}]
+    \meta{name} will be the name of the chem environment. \meta{math name} is
+    the underlying math environment.
+  \command{ProvideChemReaction}[\marg{name}\oarg{number of arguments}\marg{math name}]
+    \meta{name} will be the name of the new chem environment. \meta{math name} is
+    the underlying math environment.  The new environment is only defined if
+    it doesn't exist, yet.
+\end{commands}
+
+\begin{sourcecode}
+  \NewChemReaction{reaction}  {equation}
+  \NewChemReaction{reaction*} {equation*}
+  \NewChemReaction{reactions} {align}
+  \NewChemReaction{reactions*}{align*}
+\end{sourcecode}
+
+Let's suppose, you'd like to have the alignment behaviour of the \env{alignat}
+environment for \chemformula\ reactions.  You could do the following:
+
+\begin{sourcecode}
+  \NewChemReaction{reactionsat}[1]{alignat}
+\end{sourcecode}
+
+With this the \env{reactionsat} environment is defined.
+\begin{example}
+  \NewChemReaction{reactionsat}[1]{alignat}
+  \NewChemReaction{reactionsat*}[1]{alignat*}
+  \begin{reactionsat}{3}
+    A     &-> B     &&-> C     &&-> D \\
+    aaaaa &-> bbbbb &&-> ccccc &&-> ddddd
+  \end{reactionsat}
+  \begin{reactionsat*}{2}
+    A     &-> B     & C            &-> D  \\
+    aaaaa &-> bbbbb &\quad{} ccccc &-> ddddd
+  \end{reactionsat*}
+\end{example}
+
+\subsubsection{List of Reactions}
+
+The \chemmodule{reactions} module also provides a command to display a list of
+the reactions created with the \env{reaction} environment.
+\begin{commands}
+  \command{listofreactions}
+    Print a list of reactions.
+\end{commands}
+\begin{example}
+  \listofreactions
+\end{example}
+
+The output of this list can be modified by two options:
+\begin{options}
+  \keyval{list-name}{name of the list}\Module{reaction}\Default{List of
+    reactions}
+    Let's you set the name of the list manually.  The default name is language
+    dependent, see section~\vref{sec:lang-module}.
+  \keyval{list-entry}{prefix to each entry}\Module{reaction}\Default{Reaction}
+    Let's you set a prefix to each list entry.  The default name is language
+    dependent, see section~\vref{sec:lang-module}.
+\end{options}
+Instead of using the option \option{list-name} you also could redefine
+\cs{reactionlistname}.
+
+The list lists all reactions with a number and disregards reactions without
+number.  All reaction environments without star have an optional argument
+which let's you add a description (or caption) for the entry in the list.
+\begin{example}
+  \begin{reaction}[Autoprotolyse]
+    2 H2O <<=> H3O+ + OH-
+  \end{reaction}
+\end{example}
+
+If you use the \env{reactions} environment this will not work, though.  In
+this case you can use
+\begin{commands}
+  \command{AddRxnDesc}[\marg{description}]
+    Add a description to a reaction.
+\end{commands}
+
+\begin{example}
+  \begin{reactions}
+    "\chlewis{0.}{Cl}" + CH4  &
+      -> HCl + "\chlewis{180.}{C}" H3 \AddRxnDesc{first~step~of~chain} \\
+    "\chlewis{180.}{C}" H3 + Cl2 &
+      -> CH3Cl + "\chlewis{0.}{Cl}" \AddRxnDesc{second~step~of~chain}
+  \end{reactions}
+\end{example}
+
+\subsection{The \chemmodule*{redox} Module}\label{sec:redox-module}
+
+The \chemmodule{redox} module loads the modules \chemmodule{tikz} and
+\chemmodule{xfrac}. It also loads the packages
+\pkg{mathtools}~\cite{pkg:mathtools} and \pkg{relsize}~\cite{pkg:relsize}.
+
+\subsubsection{Oxidation Numbers}\label{sec:oxidation-numbers}
+
+Regarding the typesetting of oxidation numbers
+\citetitle{iupac:greenbook}~\cite{iupac:greenbook} says the following:
+\begin{cnltxquote}[{\cite[][p.\,50]{iupac:greenbook}}]
+  Oxidation numbers are denoted by positive or negative Roman numerals or by
+  zero \textelp{}
+
+  \textit{Examples}\quad \ox{7,Mn}, \ox[pos=side]{7,manganese}, \ox{-2,O},
+  \ox{0,Ni}
+\end{cnltxquote}
+
+The following command is provided to set oxidation numbers:
+\begin{commands}
+  \command{ox}[\sarg\oarg{options}\Marg{\meta{number},\meta{atom}}]
+    Places \meta{number} as right superscript to \meta{atom}; \meta{number}
+    has to be a (rational) number!  \meta{atom} is treated as a \chemformula\
+    formula, like it would be in \cs{chcpd}.
+\end{commands}
+
+\begin{example}
+  \ox{+1,Na}, \ox{2,Ca}, \ox{-2,S}, \ox{-1,F}
+\end{example}
+
+There are a number of options that can be used to modify the typeset result:
+\begin{options}
+  \keybool{parse}\Module{redox}\Default{true}
+    When \code{false} an arbitrary entry can be used for \code{<number>}.
+  \keybool{roman}\Module{redox}\Default{false}
+    Switches from roman to arabic numbers.
+  \keychoice{pos}{top,super,side}\Module{redox}\Default{super}
+    \code{top} places \meta{number} above \meta{atom}, \code{super} to the
+    upper right as superscript and \code{side} to the right and inside
+    brackets.  Both \code{super} and \code{side} follow \ac{iupac}
+    recommendation, \code{top} does not!
+  \keybool{explicit-sign}\Module{redox}\Default{false}
+    Shows the $+$ for positiv numbers and the $\pm$ for $0$.
+  \keychoice{decimal-marker}{comma,point}\Module{redox}\Default{point}
+    Choice for the decimal marker for formal oxidation numbers like \ox{1.2,X}.
+  \keychoice{align}{center,right}\Module{redox}\Default{center}
+    Center the oxidation number relative to the atom or right-align it.
+  \keyval{side-connect}{code}\Module{redox}\Default{\cs*{,}}
+    Code that is inserted between atom and oxidation number if
+    \keyis{pos}{side} is used.
+  \keyval{text-frac}{cs}\Module{redox}\Default{\cs{chemfrac}\Oarg{text}\Marg{\#1}\Marg{\#2}}
+    The fraction macro that is used for fractions if \keyis{pos}{side} is
+    used.  \meta{cs} must be a macro that takes two mandatory arguments, the
+    first for the numerator and the second for the denominator.
+  \keyval{super-frac}{cs}\Module{redox}\Default{\cs{chemfrac}\Oarg{superscript}%
+    \Marg{\#1}\Marg{\#2}}
+    The fraction macro that is used for fractions if \keyis{pos}{top} or
+    \keyis{pos}{super} is used.  \meta{cs} must be a macro that takes two
+    mandatory arguments, the first for the numerator and the second for the
+    denominator.
+\end{options}
+
+\begin{example}[side-by-side]
+  \ox[roman=false]{2,Ca} \ox{2,Ca} \\
+  \ox[pos=top]{3,Fe}-Oxide \\
+  \ox[pos=side]{3,Fe}-Oxide \\
+  \ox[parse=false]{?,Mn} \\
+  \ox[pos=top,align=right]{2,Ca}
+\end{example}
+
+The \keyis{pos}{top} variant also can be set with the shortcut \cs{ox}\sarg:
+\begin{example}[side-by-side]
+  \ox{3,Fe} \ox*{3,Fe}
+\end{example}
+
+Using the \option{explicit-sign} option will always show the sign of the
+oxidation number:
+\begin{example}
+  \chemsetup[redox]{explicit-sign = true}
+  \ox{+1,Na}, \ox{2,Ca}, \ox{-2,S}, \ch{"\ox{0,F}" {}2}
+\end{example}
+
+\begin{example}
+  \chemsetup[redox]{pos=top}
+  Compare \ox{-1,O2^2-} to \ch{"\ox{-1,O}" {}2^2-}
+\end{example}
+
+Sometimes one might want to use formal oxidation numbers like \num{.5} or
+\chemfrac{1}{3}:
+\begin{example}[side-by-side]
+  \chemsetup[redox]{pos=top}
+  \ox{.5,Br2}
+  \ch{"\ox{1/3,I}" {}3+}
+
+  \chemsetup[redox]{pos=side}
+  \ox{1/3,I3+}
+\end{example}
+
+The fraction is displayed with the help of the \pkg{xfrac}
+package~\cite{bnd:l3packages}.  For more details on how \chemmacros\ uses it
+read section~\vref{sec:xfrac-module}.
+
+\subsubsection{Redox Reactions}\label{sec:redox-reactions}
 
 \chemmacros\ provides two commands to visualize the transfer of electrons in
 redox reactions.  Both commands are using \TikZ.
@@ -1473,7 +2340,7 @@ The default length of the vertical lines can be customized with the option
   \OX{a,Na} $\rightarrow$ \OX{b,Na}\pch\redox(a,b)[->,red]{ox}
 \end{example}
 
-Examples:\nopagebreak% TODO: watch pagebreaks!
+\paragraph{Examples}
 \begin{example}
   \vspace{7mm}
   \ch{
@@ -1489,9 +2356,9 @@ Examples:\nopagebreak% TODO: watch pagebreaks!
 \begin{example}
   \vspace{7mm}
   \ch{
-    2 "\OX{o1,\ox{0,Na}}" + "\OX{r1,\ox{0,Cl}}" {}2
+    2 "\OX{o1,\ox*{0,Na}}" + "\OX{r1,\ox*{0,Cl}}" {}2
     ->
-    2 "\OX{o2,\ox{+1,Na}}" {}+ + 2 "\OX{r2,\ox{-1,Cl}}" {}-
+    2 "\OX{o2,\ox*{+1,Na}}" {}+ + 2 "\OX{r2,\ox*{-1,Cl}}" {}-
   }
   \redox(o1,o2){\small OX: $- 2\el$}
   \redox(r1,r2)[][-1]{\small RED: $+ 2\el$}
@@ -1501,9 +2368,9 @@ Examples:\nopagebreak% TODO: watch pagebreaks!
 \begin{example}
   \vspace{14mm}
   \ch{
-    2 "\OX{o1,\ox{0,Na}}" + "\OX{r1,\ox{0,Cl}}" {}2
+    2 "\OX{o1,\ox*{0,Na}}" + "\OX{r1,\ox*{0,Cl}}" {}2
     ->
-    2 "\OX{o2,\ox{+1,Na}}" {}+ + 2 "\OX{r2,\ox{-1,Cl}}" {}-
+    2 "\OX{o2,\ox*{+1,Na}}" {}+ + 2 "\OX{r2,\ox*{-1,Cl}}" {}-
   }
   \redox(o1,o2)[draw=red,->][3.33]{\small OX: $- 2\el$}
   \redox(r1,r2)[draw=blue,->]{\small RED: $+ 2\el$}
@@ -1512,183 +2379,71 @@ Examples:\nopagebreak% TODO: watch pagebreaks!
 \begin{example}
   \vspace{7mm}
   \ch{
-    2 "\OX{o1,\ox{0,Na}}" + "\OX{r1,\ox{0,Cl}}" {}2
-    -> 2 "\OX{o2,\ox{+1,Na}}" {}+ + 2 "\OX{r2,\ox{-1,Cl}}" {}-
+    2 "\OX{o1,\ox*{0,Na}}" + "\OX{r1,\ox*{0,Cl}}" {}2
+    -> 2 "\OX{o2,\ox*{+1,Na}}" {}+ + 2 "\OX{r2,\ox*{-1,Cl}}" {}-
   }
   \redox(o1,o2)[green,-stealth]{\small OX}
   \redox(r1,r2)[purple,-stealth][-1]{\small RED}
   \vspace{7mm}
 \end{example}
 
-\section{(Standard) State, Thermodynamics}\label{sec:stand-state-therm}
-\subsection{Thermodynamic Variables}\label{sec:therm-vari}
-
-The following commands use \pkg{siunitx}:
-\begin{commands}
-  \command{Enthalpy}[\oarg{options}\darg{subscript}\marg{value}]
-    Typeset the amount of enthalpy.
-  \command{Entropy}[\oarg{options}\darg{subscript}\marg{value}]
-    Typeset the amount of entropy.
-  \command{Gibbs}[\oarg{options}\darg{subscript}\marg{value}]
-    Typeset the amount of Gibbs enthalpy.
-\end{commands}
-
-Their usage is pretty much self-explaining:
-\begin{example}[side-by-side]
-  \Enthalpy{123} \par
-  \Entropy{123} \par
-  \Gibbs{123}
-\end{example}
-The argument \darg{subscript} adds a subscript for specification:
-\cs{Enthalpy}\Darg{r}\Marg{123} \Enthalpy(r){123}.
-
-There are several keys to customize the commands.  They do not belong to a
-module and can only be used in the optional arguments of the commands.
-\begin{options}
-  \keyval{exponent}{anything}
-    Choose \meta{anything} as exponent.
-  \keychoice{delta}{\meta{anything},false}
-    Disable or choose a symbol in front of the main symbol.  \meta{anything}
-    will be placed in math mode!
-  \keychoice{subscript}{left,right}
-    Choose if the subscript is placed to the left or the right of the main
-    symbol.
-  \keyval{unit}{unit}
-    Set the unit of the variable.
-\end{options}
-
-The default values depend on the command.
-\begin{example}[side-by-side]
-  \Enthalpy[unit=\kilo\joule]{-285} \par
-  \Gibbs[delta=false]{0} \par
-  \Entropy[delta=\Delta,exponent=]{56.7}
-\end{example}
-The unit is set corresponding to the rules of \pkg{siunitx} and depends on
-its settings:
-\begin{example}[side-by-side]
-  \Enthalpy{-1234.56e3} \par
-  \sisetup{
-    per-mode=symbol,
-    exponent-product=\cdot,
-    output-decimal-marker={,},
-    group-four-digits=true
-  }
-  \Enthalpy{-1234.56e3}
-\end{example}
+\subsection{The \chemmodule*{scheme} Module}\label{sec:scheme-module}
 
-\subsubsection{Create New Variables or Redefine Existing Ones}\label{sec:create-new-variables}
+The \chemmodule{scheme} module defines a floating environment
+\showenv{scheme}.  That is, it \emph{only} defines this float if no
+environment \env{scheme} exists at begin document.  The module checks for
+different available float defining methods, in \emph{this} order:
+\begin{itemize}
+  \item If the current class is a \KOMAScript\ class \cs*{DeclareNewTOC} will
+    be used.
+  \item If the current class is \cls{memoir}, \cls{memoir}'s methods are used.
+  \item If the package \pkg{tocbasic} has been loaded \cs*{DeclareNewTOC} will
+    be used.
+  \item If the package \pkg{newfloat} has been loaded
+    \cs*{DeclareFloatingEnvironment} will be used.
+  \item If the package \pkg{float} has been loaded its method will be used.
+  \item If neither of the above the \enquote{manual} method is used.  This
+    means the environment is defined the same way like \env*{figure} is
+    defined in the \cls*{article} class or the \cls*{book} class, depending if
+    \cs*{chapter} is defined or not.
+\end{itemize}
 
+The list name and the caption name both are translated to the language
+specified according to the \option{lang} option and the provided translations,
+see section~\vref{sec:lang-module} for details. If you want to manually change
+them then redefine these macros after begin document:
 \begin{commands}
-  \command{NewChemState}[\marg{name}\oarg{options}\marg{symbol}\marg{unit}]
-    \sinceversion{4.3}Define new corresponding commands.  \meta{name} may
-    either be a control sequence token or a control sequence name without
-    leading backslash.  This means that \cs{DeclareChemState}\Marg{name} and
-    \cs{DeclareChemState}\Marg{\cs*{name}} are equivalent.  The reason for
-    this rather strange definition is a syntax change in \cs{DeclareChemState}
-    while retaining backwards compaitibility. The latter version is
-    recommended though and the former version may deprecate in the future.
-    Gives an error if \meta{name} already exists
-  \command{RenewChemState}[\marg{name}\oarg{options}\marg{symbol}\marg{unit}]
-    Redefine existing state commands.  \meta{name} may either be a control
-    sequence token or a control sequence name without leading backslash.
-    \changedversion{4.2}This means that \cs{RenewChemState}\Marg{name} and
-    \cs{RenewChemState}\Marg{\cs*{name}} are equivalent.  The reason for
-    this rather strange definition is a syntax change in \cs{RenewChemState}
-    while retaining backwards compaitibility. The latter version is
-    recommended though and the former version may deprecate in the future.
-  \command{DeclareChemState}[\marg{name}\oarg{options}\marg{symbol}\marg{unit}]
-    \changedversion{4.3}Like \cs{NewChemState} but gives now error if
-    \meta{name} already exists.
+  \command{listschemename}
+    The name of the list of schemes.
+  \command{schemename}
+    The name used in captions.
 \end{commands}
-
-\begin{example}
-  \NewChemState\Helmholtz{A}{\kilo\joule\per\mole}
-  \NewChemState\ElPot[subscript-left=false,exponent=]{E}{\volt}
-  \Helmholtz{123.4} \par
-  \ElPot{-1.1} \par
-  \ElPot[exponent=0]($\ch{Sn}|\ch{Sn^2+}||\ch{Pb^2+}|\ch{Pb}$){0.01}
-\end{example}
-
-The command has some keys with which the default behaviour of the new command
-can be set.
-\begin{options}
-  \keyval{exponent}{anything}\Default{\cs{standardstate}}
-    Set the default exponent.
-  \keychoice{delta}{\meta{anything},false}\Default{\cs{changestate}}
-    Choose the default ``delta'' symbol that is placed in front of the
-    main symbol.  \meta{anything} will be placed in math mode!
-  \keybool{subscript-left}\Default{true}
-    Choose the default position of the sybscript.
-  \keyval{subscript}{anything}\Default
-    Choose the default subscript symbol.
-\end{options}
-
-\begin{example}[side-by-side]
-  \RenewChemState\Enthalpy{h}{\joule}
-  \Enthalpy(f){12.5}
-\end{example}
-
-The existing commands have been defined like this:
-\begin{sourcecode}
-  \NewChemState\Enthalpy{H}{\kilo\joule\per\mole}
-  \NewChemState\Entropy[delta=false,subscript-left=false]{S}
-    {\joule\per\kelvin\per\mole}
-  \NewChemState\Gibbs{G}{\kilo\joule\per\mole}
-\end{sourcecode}
-
-So -- for following thermodynamic conventions -- one could define a molar and
-an absolute variable:
-\begin{example}
-  \NewChemState\enthalpy[exponent=]{h}{\kilo\joule\per\mole}% molar
-  \RenewChemState\Enthalpy[exponent=]{H}{\kilo\joule}% absolute
-  \enthalpy{-12.3} \Enthalpy{-12.3}
-\end{example}
-
-\subsection{State}\label{ssec:state}
-
-The commands presented in section~\ref{sec:therm-vari} internally all use the
-command\footnote{Please note that \marg{subscript} is an \emph{optional}
-  argument.}
+The list of schemes is printed as expected with
 \begin{commands}
-  \command{State}[\oarg{options}\marg{symbol}\marg{subscript}]
-    Typeset a state variable.
+  \command{listofschemes}
 \end{commands}
 
-It can be used to write the thermodynamic state variables without value and
-unit.
+\subsection{The \chemmodule*{spectroscopy} Module}\label{sec:spectroscopy-module}
 
-\begin{example}
-  \State{A}, \State{G}{f},
-  \State[subscript-left=false]{E}{\ch{Na}},
-  \State[exponent=\SI{1000}{\celsius}]{H}
-\end{example}
+The \chemmodule{spectroscopy} module loads the \chemmodule{chemformula} module
+and the \pkg{siunitx} package~\cite{pkg:siunitx}.
 
-Again there are some keys to customize the command:
-\begin{options}
-  \keyval{exponent}{anything}\Module{state}
-    Set the default exponent symbol.
-  \keybool{subscript-left}\Module{state}
-    Set the default subscript position.
-  \keychoice{delta}{\meta{anything},false}\Module{state}
-    Set the default ``delta'' symbol.  \meta{anything} will be placed in math
-    mode!
-\end{options}
-
-\section{Spectroscopy and Experimental Data}\label{sec:spektroskopie}
-\subsection{The \cs*{NMR} Command}
+\subsubsection{The \cs*{NMR} Command}
 
 When you're trying to find out if a compound is the one you think it is often
 NMR spectroscopy is used.  The experimental data are typeset similar to this:
 \begin{center}
   \NMR(400)[CDCl3] = \num{1.59}
 \end{center}
-\chemmacros\ provides a command which simplifies the input (uses
-\pkg{siunitx}).
+The \chemmodule{spectroscopy} module provides a command which simplifies the
+input.
 
 \begin{commands}
   \command{NMR}[\sarg\Marg{\meta{num},\meta{element}}%
     \Darg{\meta{num},\meta{unit}}\oarg{solvent}]
-    Typeset nuclear magnetic resonance data.
+    Typeset nuclear magnetic resonance data. \meta{num} is a valid
+    \pkg{siunitx} number input, \meta{unit} is a valid \pkg{siunitx} unit
+    input.  \meta{solvent} is any valid \chemformula\ input as in \cs{chcpd}.
 \end{commands}
 
 \emph{All} Argument are optional! Without arguments we get:
@@ -1721,20 +2476,22 @@ The third argument specifies the solvent:
   \NMR[CDCl3]
 \end{example}
 
-\subsection{Short Cuts}
+\subsubsection{Short Cuts}
 
 It is possible to define short cut commands for specific nuclei.
 \begin{commands}
   \command{NewChemNMR}[\marg{cs}\Marg{\meta{num},\meta{atom}}]
-    \sinceversion{4.3}Define a new shortcut macro for typesetting a certain
-    type of magnetic resonence data.  Gives an error if \meta{cs} already
-    exists.
+    Define a new shortcut macro for typesetting a certain type of magnetic
+    resonence data.  Gives an error if \meta{cs} already exists.
   \command{DeclareChemNMR}[\marg{cs}\Marg{\meta{num},\meta{atom}}]
-    \changedversion{4.3}Define a new shortcut macro for typesetting a certain
-    type of magnetic resonence data.
+    Define a new shortcut macro for typesetting a certain type of magnetic
+    resonence data.  Overwrites an existing macro.
   \command{RenewChemNMR}[\marg{cs}\Marg{\meta{num},\meta{atom}}]
     Redefine an existing shortcut macro for typesetting a certain type of
-    magnetic resonence data.
+    magnetic resonence data.  Gives an error if \meta{cs} doesn't exist.
+  \command{ProvideChemNMR}[\marg{cs}\Marg{\meta{num},\meta{atom}}]
+    Define a new shortcut macro for typesetting a certain type of magnetic
+    resonence data.  \meta{cs} is only defined if it doesn't exist, yet.
 \end{commands}
 
 This defines a command with the same arguments as \cs{NMR} \emph{except} for
@@ -1746,9 +2503,10 @@ This defines a command with the same arguments as \cs{NMR} \emph{except} for
   \HNMR*(400)
 \end{example}
 
-\subsection{An Environment to Typeset Experimental Data}
+\subsubsection{An Environment to Typeset Experimental Data}
 
-\chemmacros\ provides an environment to ease the input of experimental data.
+The \chemmodule{spectroscopy} module provides an environment to ease the input
+of experimental data.
 \begin{environments}
   \environment{experimental}
     Environment for the output of experimental data.  Inside the environment
@@ -1767,7 +2525,7 @@ This defines a command with the same arguments as \cs{NMR} \emph{except} for
     \cs{NMR}\Marg{13,C[\textasciicircum 1H]} \NMR{13,C[^1H]}
   \command{J}[\Darg{\meta{bonds};\meta{nuclei}}\oarg{unit}\marg{list of nums}]
     Coupling constant, values are input separated by \code{;} (NMR).  The
-    argument \Darg{\meta{bonds};\meta{nuclei}} and \oarg{unit} are optional
+    arguments \Darg{\meta{bonds};\meta{nuclei}} and \oarg{unit} are optional
     and enable further specifications of the coupling.
   \command{\#}[\marg{num}]
     Number of nuclei (NMR).
@@ -1787,57 +2545,54 @@ This defines a command with the same arguments as \cs{NMR} \emph{except} for
   \end{experimental}
 \end{example}
 
-\subsection{Customization}\label{sec:experimental-customization}
+\paragraph{Customization}\label{sec:experimental-customization}
 
 The output of the environment and of the NMR commands can be customized be a
 number of options.  For historical reasons they all belong to the module
 \module{nmr}.
 \begin{options}
-  \keyval{unit}{unit}\Module{nmr}\Default{\cs*{mega}\cs*{hertz}}
+  \keyval{unit}{unit}\Module{spectroscopy}\Default{\cs*{mega}\cs*{hertz}}
     The used default unit.
-  \keychoice{nucleus}{\Marg{\meta{num},\meta{atom}}}\Module{nmr}\Default{\Marg{1,H}}
+  \keychoice{nucleus}{\Marg{\meta{num},\meta{atom}}}\Module{spectroscopy}\Default{\Marg{1,H}}
     The used default nucleus.
-  \keyval{connector}{code}\Default{-}
-    \sinceversion{4.7}Places \meta{code} between the nucleus and the method.
-  \keyval{method}{code}\Default{NMR}
-    \sinceversion{4.7}The measuring method.
-  \keyval{format}{commands}\Module{nmr}\Default
+  \keyval{connector}{code}\Module{spectroscopy}\Default{-}
+    Places \meta{code} between the nucleus and the method.
+  \keyval{method}{code}\Module{spectroscopy}\Default{NMR}
+    The measuring method.
+  \keyval{format}{commands}\Module{spectroscopy}\Default
     For example \cs*{bfseries}.
-  \keychoice{pos-number}{side,sub,super}\Module{nmr}\Default{side}
-    \changedversion{4.3}Position of the number next to the atom.
-  \keyval{coupling-symbol}{code}\Module{nmr}\Default{J}
-    \sinceversion{4.3}The symbol used for the coupling constant.
-  \keyval{coupling-unit}{unit}\Module{nmr}\Default{\cs*{hertz}}
+  \keychoice{pos-number}{side,sub,super}\Module{spectroscopy}\Default{side}
+    Position of the number next to the atom.
+  \keyval{coupling-symbol}{code}\Module{spectroscopy}\Default{J}
+    The symbol used for the coupling constant.
+  \keyval{coupling-unit}{unit}\Module{spectroscopy}\Default{\cs*{hertz}}
     A \pkg{siunitx} unit.
-  \keychoice{coupling-pos}{side,sub}\Module{nmr}\Default{side}
-    \sinceversion{4.3}Placement of the coupling nuclei next to the symbol
-    $J$ (or rather the symbol specified with option
-    \option{coupling-symbol}).
-  \keyval{coupling-nuclei-pre}{code}\Module{nmr}\Default{(}
-    \sinceversion{4.3}Code inserted before the coupling nuclei when
-    \keyis{coupling-pos}{side}.
-  \keyval{coupling-nuclei-post}{code}\Module{nmr}\Default{)}
-    \sinceversion{4.3}Code inserted after the coupling nuclei when
-    \keyis{coupling-pos}{side}.
-  \keyval{coupling-bonds-pre}{code}\Module{nmr}\Default
-    \sinceversion{4.3}Code inserted before the coupling bonds.
-  \keyval{coupling-bonds-post}{code}\Module{nmr}\Default{\cs*{!}}
-    \sinceversion{4.3}Code inserted after the coupling bonds.
-  \keyval{coupling-pos-cs}{cs}\Module{nmr}\Default{\cs*{@firstofone}}
-    \sinceversion{4.4}Set the macro that prints the number set with the
-    \cs{pos} macro.  This needs to be a command with one mandatory argument.
-  \keyval{atom-number-cs}{cs}\Module{nmr}\Default{\cs*{@firstofone}}
-    \sinceversion{4.4}Set the macro that prints the number set with the
-    \cs{\#} macro.  This needs to be a command with one mandatory argument.
-  \keybool{parse}\Module{nmr}\Default{true}
+  \keychoice{coupling-pos}{side,sub}\Module{spectroscopy}\Default{side}
+    Placement of the coupling nuclei next to the symbol $J$ (or rather the
+    symbol specified with option \option{coupling-symbol}).
+  \keyval{coupling-nuclei-pre}{code}\Module{spectroscopy}\Default{(}
+    Code inserted before the coupling nuclei when \keyis{coupling-pos}{side}.
+  \keyval{coupling-nuclei-post}{code}\Module{spectroscopy}\Default{)}
+    Code inserted after the coupling nuclei when \keyis{coupling-pos}{side}.
+  \keyval{coupling-bonds-pre}{code}\Module{spectroscopy}\Default
+    Code inserted before the coupling bonds.
+  \keyval{coupling-bonds-post}{code}\Module{spectroscopy}\Default{\cs*{!}}
+    Code inserted after the coupling bonds.
+  \keyval{coupling-pos-cs}{cs}\Module{spectroscopy}\Default{\cs*{@firstofone}}
+    Set the macro that prints the number set with the \cs{pos} macro.  This
+    needs to be a command with one mandatory argument.
+  \keyval{atom-number-cs}{cs}\Module{spectroscopy}\Default{\cs*{@firstofone}}
+    Set the macro that prints the number set with the \cs{\#} macro.  This
+    needs to be a command with one mandatory argument.
+  \keybool{parse}\Module{spectroscopy}\Default{true}
     Treat the solvent as \chemformula\ formula or not.
-  \keyval{delta}{tokens}\Module{nmr}\Default
+  \keyval{delta}{tokens}\Module{spectroscopy}\Default
     The \meta{tokens} are added after $\delta$.
-  \keybool{list}\Module{nmr}\Default{false}
+  \keybool{list}\Module{spectroscopy}\Default{false}
     The environment \env{nmr}[<optionen>]{} is formatted as a list
-  \keyval{list-setup}{setup}\Module{nmr}
+  \keyval{list-setup}{setup}\Module{spectroscopy}
     Setup of the list. See below for the default settings.
-  \keybool{use-equal}\Module{nmr}\Default{false}
+  \keybool{use-equal}\Module{spectroscopy}\Default{false}
     Add egual sign after \cs{NMR} and \cs{data}.
 \end{options}
 
@@ -1867,8 +2622,7 @@ can be used like \cs{data} for the NMR data.
   \end{experimental}
 \end{example}
 
-\subsection{An Example}
-
+\paragraph{An Example}
 The code below is shown with different specifications for \meta{options}.
 Of course options can also be chosen with \cs{chemsetup}.
 
@@ -1914,9 +2668,9 @@ Of course options can also be chosen with \cs{chemsetup}.
   \end{experimental}
 \end{sourcecode}
 
-\subsubsection{Nearly Standard}
-
+\paragraph{Nearly Standard}
 Output with these options:
+
 \begin{sourcecode}
   delta=(ppm),pos-number=sub,use-equal
 \end{sourcecode}
@@ -1961,8 +2715,9 @@ Output with these options:
   \data*{quantum yield} $\Phi = \val{0.74+-0.1}$\,.
 \end{experimental}
 
-\subsubsection{Formatted List}
+\paragraph{Formatted List}
 Output with these options:
+
 \begin{sourcecode}
   format=\bfseries,delta=(ppm),list=true,use-equal
 \end{sourcecode}
@@ -2007,9 +2762,9 @@ Output with these options:
   \data*{quantum yield} $\Phi = \val{0.74+-0.1}$\,.
 \end{experimental}
 
-\subsubsection{Crazy}
-
+\paragraph{Crazy}
 Output for these options:
+
 \begin{sourcecode}
   format=\color{red}\itshape,
   list=true,
@@ -2066,482 +2821,429 @@ Output for these options:
   \data*{quantum yield} $\Phi = \val{0.74+-0.1}$\,.
 \end{experimental}
 
-\section{Reaction Environments}\label{sec:reactions}
-\subsection{Defined by \chemmacros}
-
-You can use these environments for numbered\ldots
-\begin{environments}
-  \environment{reaction}
-    A single reaction where \chemformula\ code is placed directly in the
-    environment body.  A wrapper around the \env*{equation} environment.
-  \environment{reactions}
-    Several aligned reactions.  A wrapper around \pkg{amsmath}'s \env*{align}
-    environment.
-\end{environments}
+\subsection{The \chemmodule*{thermodynamics} Module}\label{sec:thermodynamics-module}
 
-\ldots and their starred versions for unnumbered reactions.
-\begin{environments}
-  \environment{reaction*}
-    A wrapper around the \env*{equation*} environment.
-  \environment{reactions*}
-    A wrapper around \pkg{amsmath}'s \env*{align*} environment.
-\end{environments}
+The \chemmodule{thermodynamics} module loads the \pkg{siunitx}
+package~\cite{pkg:siunitx}.
 
-With them you can create (un)numbered reaction equations similar to
-mathematical equations.
+\subsubsection{The \cs*{state} Macro}
 
-Theses environments use the \env*{equation}/\env*{equation*} environments or
-the \env*{align}/\env*{align*} environments, respectively, to display the
-reactions.
+\begin{commands}
+  \command{state}[\oarg{options}\marg{symbol}]
+    Typeset a state variable.
+\end{commands}
 
+This macro can be used to write the thermodynamic state variables.
 \begin{example}
-  Reaction with counter:
-  \begin{reaction}
-    A -> B
-  \end{reaction}
+  \state{A}, \state[subscript-left=f]{G} ,
+  \state[subscript-right=\ch{Na}]{E},
+  \state[superscript-right=\SI{1000}{\celsius}]{H}
 \end{example}
 
-\begin{example}
-  Reaction without counter:
-  \begin{reaction*}
-    C -> D
-  \end{reaction*}
-\end{example}
+These options are available:
+\begin{options}
+  \keyval{pre}{text}\Module{thermodynamics}\Default{\cs{changestate}}
+    Code inserted before the variable.  Inserted in text mode.
+  \keyval{post}{text}\Module{thermodynamics}\Default
+    Code inserted after the variable. Inserted in text mode.
+  \keyval{superscript-left}{text}\Module{thermodynamics}\Default
+    The left superscript. Inserted in text mode.
+  \keyval{superscript-right}{text}\Module{thermodynamics}\Default{\cs{standardstate}}
+    The right superscript. Inserted in text mode.
+  \keyval{superscript}{text}\Module{thermodynamics}
+    An alias of \option{superscript-right}.
+  \keyval{subscript-left}{text}\Module{thermodynamics}\Default
+    The left subscript. Inserted in text mode.
+  \keyval{subscript-right}{text}\Module{thermodynamics}\Default
+    The right subscript. Inserted in text mode.
+  \keyval{subscript}{text}\Module{thermodynamics}
+    An alias of \option{subscript-left}.
+\end{options}
 
-\begin{example}
-  Several aligned reactions with counter:
-  \begin{reactions}
-    A     &-> B + C \\
-    D + E &-> F
-  \end{reactions}
-\end{example}
+\subsubsection{Thermodynamic Variables}
 
-\begin{example}
-  Several aligned reactions without counter:
-  \begin{reactions*}
-    G     &-> H + I \\
-    J + K &-> L
-  \end{reactions*}
-\end{example}
+The \chemmodule{thermodynamics} module provides a few commands for specific
+thermodynamic variables:
+\begin{commands}
+  \command{enthalpy}[\sarg\oarg{options}\darg{subscript}\marg{value}]
+    Typeset the amount of enthalpy.
+  \command{entropy}[\sarg\oarg{options}\darg{subscript}\marg{value}]
+    Typeset the amount of entropy.
+  \command{gibbs}[\sarg\oarg{options}\darg{subscript}\marg{value}]
+    Typeset the amount of Gibbs enthalpy.
+\end{commands}
 
-If you want to change the layout of the counter tags, you can use
+Their usage is pretty much self-explaining:
+\begin{example}[side-by-side]
+  \enthalpy{123} \par
+  \entropy{123} \par
+  \gibbs{123}
+\end{example}
+The argument \darg{subscript} adds a subscript for specification, \sarg\ hides
+number and unit:
+\begin{example}[side-by-side]
+    \enthalpy(r){123} \par
+    \enthalpy*{123} \par
+\end{example}
 
-\cs{renewtagform}\marg{tagname}\oarg{format}\marg{right delimiter}\marg{left
-  delimiter}\footnote{Provided by the \pkg{mathtools} package}.
+\begin{options}
+  \keyval{pre}{text}\Module{thermodynamics}\Default{\cs{changestate}}
+    Code inserted before the variable.  Inserted in text mode.
+  \keyval{post}{text}\Module{thermodynamics}\Default
+    Code inserted after the variable.  Inserted in text mode.
+  \keyval{superscript-left}{text}\Module{thermodynamics}\Default
+    The left superscript.  Inserted in text mode.
+  \keyval{superscript-right}{text}\Module{thermodynamics}\Default{\cs{standardstate}}
+    The right superscript. Inserted in text mode.
+  \keyval{superscript}{text}\Module{thermodynamics}
+    An alias of \option{superscript-right}.
+  \keyval{subscript-left}{text}\Module{thermodynamics}\Default
+    The left subscript.  Inserted in text mode.
+  \keyval{subscript-right}{text}\Module{thermodynamics}\Default
+    The right subscript.  Inserted in text mode.
+  \keyval{subscript}{text}\Module{thermodynamics}
+    An alias of \option{subscript-left}.
+  \keychoice{subscript-pos}{left,right}\Module{thermodynamics}\Default{left}
+    Determines wether the subscript given in \darg{subscript} is placed to the
+    left or the right of the variable.
+  \keyval{symbol}{symbol}\Module{thermodynamics}\Default
+    The symbol of the variable.  Inserted in math mode.
+  \keyval{unit}{unit}\Module{thermodynamics}\Default
+    A valid \pkg{siunitx} unit.
+\end{options}
 
-\begin{example}
-  \renewtagform{reaction}[R \textbf]{[}{]}
-  \begin{reaction}
-    H2O + CO2 <<=> H2CO3
-  \end{reaction}
+The default values depend on the command.
+\begin{example}[side-by-side]
+  \enthalpy[unit=\kilo\joule]{-285} \par
+  \gibbs[pre=]{0} \par
+  \entropy[pre=$\Delta$,superscript=]{56.7}
 \end{example}
-
-With version~3.3 referencing and the use of \AmS math's \cs{intertext} also
-function properly:
-\begin{example}
-  \begin{reactions}
-    A + 2 B &-> 3 C + D \label{rxn:test}
-    \intertext{Some text in between aligned reactions}
-    3 E + F &<=> G + 1/2 H
-  \end{reactions}
-  See reaction~\ref{rxn:test}.
+The unit is set corresponding to the rules of \pkg{siunitx} and depends on
+its settings:
+\begin{example}[side-by-side]
+  \enthalpy{-1234.56e3} \par
+  \sisetup{
+    per-mode=symbol,
+    exponent-product=\cdot,
+    output-decimal-marker={,},
+    group-four-digits=true
+  }
+  \enthalpy{-1234.56e3}
 \end{example}
 
-\emph{You should not use \cs{mch} and its relatives inside the \env{reaction}
-  environments.}
+\subsubsection{Create New Variables or Redefine Existing Ones}
 
-\subsection{Own Reactions}
-You can create new types of reactions with the command:
 \begin{commands}
-  \command{NewChemReaction}[\oarg{options}\marg{name}\marg{math name}]
-    \sinceversion{4.3}\meta{name} will be the name of the new environment.
-    \meta{math name} is the underlying math environment.  Gives an error if
-    \meta{name} already exists.
-  \command{DeclareChemReaction}[\oarg{options}\marg{name}\marg{math name}]
-    \changedversion{4.3}\meta{name} will be the name of the new environment.
-    \meta{math name} is the underlying math environment.
-  \command{RenewChemReaction}[\oarg{options}\marg{name}\marg{math name}]
-    \sinceversion{4.3}Renew an existing definition.
+  \command{NewChemState}[\marg{cs}\marg{options}]
+    Define new state commands like \cs{enthalpy}.  Gives an error is \meta{cs}
+    already exists.
+  \command{RenewChemState}[\marg{cs}\marg{options}]
+    Redefine existing state commands.
+  \command{DeclareChemState}[\marg{cs}\marg{options}]
+    Like \cs{NewChemState} but gives now error if \meta{cs} already exists.
+  \command{ProvideChemState}[\marg{cs}\marg{options}]
+    Define new state commands like \cs{enthalpy}.  Defines \meta{cs} only if
+    it is not defined, yet.
 \end{commands}
-
-The command has two options.
+The argument \meta{options} is a comma separated list of key/value options:
 \begin{options}
-  \keybool{star}
-    Also create a starred variant.
-  \keybool{arg}
-    Add a mandatory argument to the defined environment.
+  \keyval{pre}{text}\Module{thermodynamics}\Default{\cs{changestate}}
+    Code inserted before the variable.  Inserted in text mode.
+  \keyval{post}{text}\Module{thermodynamics}\Default
+    Code inserted after the variable.  Inserted in text mode.
+  \keyval{superscript-left}{text}\Module{thermodynamics}\Default
+    The left superscript.  Inserted in text mode.
+  \keyval{superscript-right}{text}\Module{thermodynamics}\Default{\cs{standardstate}}
+    The right superscript.
+  \keyval{superscript}{text}\Module{thermodynamics}
+    An alias of \option{superscript-right}.
+  \keyval{subscript-left}{text}\Module{thermodynamics}\Default
+    The left subscript.  Inserted in text mode.
+  \keyval{subscript-right}{text}\Module{thermodynamics}\Default
+    The right subscript.  Inserted in text mode.
+  \keyval{subscript}{text}\Module{thermodynamics}
+    An alias of \option{subscript-left}.
+  \keychoice{subscript-pos}{left,right}\Module{thermodynamics}\Default{left}
+    Determines wether the subscript given in \darg{subscript} is placed to the
+    left or the right of the variable.
+  \keyval{symbol}{symbol}\Module{thermodynamics}\Default
+    The symbol of the variable.
+  \keyval{unit}{unit}\Module{thermodynamics}\Default
+    A valid \pkg{siunitx} unit.
 \end{options}
-There is \option{star}, which will also define a starred version of the new
-environment, if the starred math environment exists.  If it doesn't exist,
-this will cause an error.
-
-Then there is \option{arg}, which is used to define an environment with a
-mandatory argument.  Of course this only works, if the used math environment
-has a mandatory argument.
-
-The predefined environments are defined via
-\begin{sourcecode}
-  \NewChemReaction[star]{reaction}{equation}
-  \NewChemReaction[star]{reactions}{align}.
-\end{sourcecode}
 
-Let's suppose, you'd like to have the alignment behaviour of the \env{alignat}
-environment for \chemformula\ reactions.  You could do the following:
+\begin{example}
+  \NewChemState\Helmholtz{ symbol=A , unit=\kilo\joule\per\mole }
+  \NewChemState\ElPot{ symbol=E , subscript-pos=right , superscript= , unit=\volt }
+  \Helmholtz{123.4} \par
+  \ElPot{-1.1} \par
+  \ElPot[superscript=0]($\ch{Sn}|\ch{Sn^2+}||\ch{Pb^2+}|\ch{Pb}$){0.01} \par
+  \RenewChemState\enthalpy{ symbol=h , unit=\joule} \par
+  \enthalpy(f){12.5}
+\end{example}
 
+The existing commands have been defined like this:
 \begin{sourcecode}
-  \NewChemReaction[star,arg]{reactionsat}{alignat}
+  \NewChemState \enthalpy{ symbol = H, unit = \kilo\joule\per\mole }
+  \NewChemState \entropy { symbol = S, unit = \joule\per\kelvin\per\mole, pre = }
+  \NewChemState \gibbs   { symbol = G, unit = \kilo\joule\per\mole }
 \end{sourcecode}
 
-With this the \env{reactionsat} environment is defined.
+So -- for following thermodynamic conventions -- one could define a molar and
+an absolute variable:
 \begin{example}
-  \NewChemReaction[star,arg]{reactionsat}{alignat}
-  \begin{reactionsat}{3}
-    A     &-> B     &&-> C     &&-> D \\
-    aaaaa &-> bbbbb &&-> ccccc &&-> ddddd
-  \end{reactionsat}
-  \begin{reactionsat*}{2}
-    A     &-> B     & C            &-> D  \\
-    aaaaa &-> bbbbb &\quad{} ccccc &-> ddddd
-  \end{reactionsat*}
+  \RenewChemState\enthalpy{symbol=h,superscript=,unit=\kilo\joule\per\mole}% molar
+  \RenewChemState\Enthalpy{symbol=H,superscript=,unit=\kilo\joule}% absolute
+  \enthalpy{-12.3} \Enthalpy{-12.3}
 \end{example}
 
-\subsection{List of Reactions}
+\subsection{The \chemmodule*{units} Module}\label{sec:units-module}
 
-\chemmacros\ also provides a command to display a list of the reactions
-created with the \env{reaction} environment.
+The \chemmodule{units} module loads the \pkg{siunitx}
+package~\cite{pkg:siunitx}.
+
+In chemistry some non-SI units are very common.  \pkg{siunitx} provides the
+command
 \begin{commands}
-  \command{listofreactions}
-    Print a list of reactions.
+  \command*{DeclareSIUnit}[\marg{cs}\marg{unit}]
+    Define \meta{cs} to be a valid unit command inside \pkg{siunitx}' macros
+    \cs*{SI} and \cs*{si} which represents \meta{unit}.
 \end{commands}
-\begin{example}
-  \listofreactions
-\end{example}
-
-The output of this list can be modified by two options:
-\begin{options}
-  \keyval{list-name}{name of the list}\Module{reaction}\Default{List of
-    reactions}
-    Let's you set the name of the list manually.  The default name is language
-    dependent, see section~\ref{sec:languages}.
-  \keyval{list-entry}{prefix to each entry}\Module{reaction}\Default{Reaction}
-    Let's you set a prefix to each list entry.  The default name is language
-    dependent, see section~\ref{sec:languages}.
-\end{options}
-Instead of using the option \option{list-name} you also could redefine
-\cs{reactionlistname}.
-
-The list lists all reactions with a number and disregards reactions without
-number.  All reaction environments without star have an optional argument
-which let's you add a description (or caption) for the entry in the list.
-\begin{example}
-  \begin{reaction}[Autoprotolyse]
-    2 H2O <<=> H3O+ + OH-
-  \end{reaction}
-\end{example}
-
-If you use the \env{reactions} environment this will not work, though.  In
-this case you can use
+to add arbitrary units.  \chemmacros\ uses that command to provide some
+units.  Like all \pkg{siunitx} units they're only valid inside
+\cs*{SI}\marg{num}\marg{unit} and \cs*{si}\marg{unit}.
 \begin{commands}
-  \command{AddRxnDesc}[\marg{description}]
-    Add a description to a reaction.
+  \command{atmosphere} \si{\atmosphere}
+  \command{atm} \si{\atm}
+  \command{calory} \si{\calory}
+  \command{cal} \si{\cal}
+  \command{cmc} \si{\cmc} \par
+    The units \cs{cmc}, \cs{molar}, and \cs{Molar} are defined by the
+    package \pkg{chemstyle} as well.  \chemmacros\ only defines them, if
+    \pkg{chemstyle} is not loaded.
+  \command{molar} \si{\molar}
+  \command{moLar} \si{\moLar}
+  \command{Molar} \si{\Molar}
+  \command{MolMass} \si{\MolMass}
+  \command{normal} \si{\normal}
+  \command{torr} \si{\torr}
 \end{commands}
 
-\begin{example}
-  \begin{reactions}
-    Cl "\Lewis{0.,\vphantom{Cl}}" + CH4  &
-      -> HCl + "\Lewis{4.,\vphantom{CH}}" CH3 \AddRxnDesc{first~step~of~chain} \\
-    "\Lewis{4.,\vphantom{CH}}" CH3 + Cl2 &
-      -> CH3Cl + Cl "\Lewis{0.,\vphantom{Cl}}" \AddRxnDesc{second~step~of~chain}
-  \end{reactions}
-\end{example}
-
-Note: you don't have to use the phantom commands if you haven't changed the
-format of the atoms (see the documentation of the \chemformula\ package for
-information on how to do this).
+By the way: \cs*{mmHg} \si{\mmHg} already is defined by \pkg{siunitx}.
 
-\section{Phases}\label{sec:phasen}
-\subsection{Basics}
+\section{Internal Modules}
 
-These commands are intended to indicate the phase of a compound.
-\begin{itemize}
-  \item[]
-    \cs{sld} \sld \quad
-    \cs{lqd} \lqd \quad
-    \cs{gas} \gas \quad
-    \cs{aq} \aq
-\end{itemize}
+\subsection{The \chemmodule*{tikz} Module}\label{sec:tikz-module}
 
-\begin{example}
-  \ch{C\sld{} + 2 H2O\lqd{} -> CO2\gas{} + 2 H2\gas}\par
-  To make it complete: NaCl\aq.
-\end{example}
+The \chemmodule{tikz} module loads the \pkg{tikz} package~\cite{pkg:pgf} and
+the \TikZ\ library \code{calc}.
 
-The \ac{iupac} recommendation to indicate the state of aggregation is to put
-it in parentheses after the compound \cite{iupac:greenbook}.  However, you
-might want to put it as a subscript which is also very common.
+\subsubsection{For Users}
+The \chemmodule{tikz} module defines a few arrow tips:
+\begin{tikzcode}
+  \arrowtip{el}
+    An arrow tip: \verbcode+\tikz\draw[-el](0,0)--(1,0);+
+    \tikz\draw[-el](0,0)--(1,0);
+  \arrowtip{left el}
+    An arrow tip: \verbcode+\tikz\draw[-left el](0,0)--(1,0);+
+    \tikz\draw[-left el](0,0)--(1,0);
+  \arrowtip{right el}
+    An arrow tip: \verbcode+\tikz\draw[-right el](0,0)--(1,0);+
+    \tikz\draw[-right el](0,0)--(1,0);
+\end{tikzcode}
 
-\begin{cnltxquote}[{\acs{iupac} Green Book {\cite[][p.\,54]{iupac:greenbook}}}]
-  The \textelp{} symbols are used to represent the states of aggregation of
-  chemical species.  The letters are appended to the formula in parentheses
-  and should be printed in Roman (upright) type without a full stop (period).
-\end{cnltxquote}
+\subsubsection{For Module Writers}
+The \chemmodule{tikz} module provides some macros for common \TikZ\
+functions.  This allows to use expl3's powerful function variants for
+expansion control.
 
-There are two options to customize the output:
-\begin{options}
-  \keychoice{pos}{side,sub}\Module{phases}\Default{side}
-    Switch the position of the phase indicator.
-  \keyval{space}{dim}\Module{phases}\Default{.1333em}
-    Change the default spacing between compound a phase indicator if
-    \keyis{pos}{side}. A \TeX\ dimension.
-\end{options}
-\begin{example}
-  \chemsetup[phases]{pos=sub}
-  \ch{C\sld{} + 2 H2O\lqd{} -> CO2\gas{} + 2 H2\gas}\par
-  To make it complete: NaCl\aq.
-\end{example}
-
-All those phase commands have an optional argument\sinceversion{4.7}:
-\begin{example}[side-by-side]
-  \ch{H2O "\lqd[\SI{5}{\celsius}]"}
-\end{example}
-
-\subsection{Define Own Phases}
-Depending on the subject of your document you might need to indicate other
-states of aggregation.  You can easily define them.
 \begin{commands}
-  \command{NewChemPhase}[\marg{cs}\oarg{german}\marg{english}]
-    \sinceversion{4.3}Define a new phase command.  Actually the optional
-    argument is an artefact of an earlier implementation of the command.  It
-    has no effect at all.  See section~\ref{sec:lang-depend} for a way to
-    define language dependent settings.  Gives an error if \meta{cs} already
-    exists.
-  \command{DeclareChemPhase}[\marg{cs}\oarg{german}\marg{english}]
-    Define a new phase command.  Actually the optional argument is an artefact
-    of an earlier implementation of the command.  It has no effect at all.
-    See section~\ref{sec:lang-depend} for a way to define language dependent
-    settings.
-  \command{RenewChemPhase}[\marg{cs}\oarg{german}\marg{english}]
-    Redefine an existing phase command.  Actually the optional argument is an
-    artefact of an earlier implementation of the command.  It has no effect at
-    all.  See section~\ref{sec:lang-depend} for a way to define language
-    dependent settings.
-  \command{phase}[\marg{phase}]
-    If you need a phase indicator just once or twice.
+  \command*{c_chemmacros_other_colon_tl}
+    A constant tokenlist which contains a colon with category code~12 (other).
+    This is useful since \TikZ\ sometimes expects an other colon and in an
+    expl3 programming environment \code{:} has category code~11 (letter).
+  \command*{chemmacros_tikz_picture:nn}[ \marg{options} \marg{code}]
+    Defined as \verbcode+\tikzpicture[{#1}] #2 \endtikzpicture+.
+  \command*{chemmacros_tikz:nn}[ \marg{options} \marg{code}]
+    Defined as \verbcode+\tikz[{#1}]{#2}+.
+  \command*{chemmacros_tikz_draw:n}[ \marg{options}]
+    Defined as \verbcode+\draw[{#1}]+.
+  \command*{chemmacros_tikz_node:n}[ \marg{options}]
+    Defined as \verbcode+\node[{#1}]+.
+  \command*{chemmacros_tikz_shade:n}[ \marg{options}]
+    Defined as \verbcode+\shade[{#1}]+.
+  \command*{chemmacros_tikz_shadedraw:n}[ \marg{options}]
+    Defined as \verbcode+\shadedraw[{#1}]+.
+  \command*{chemmacros_tikz_node_in_draw:n}[ \marg{options}]
+    Defined as \verbcode+node[{#1}]+.
 \end{commands}
 
-\cs{NewChemPhase} only defines a phase if \meta{cs} is not already used by any
-other command.  If it \emph{is} already used \chemmacros\ will either give an
-error \cs{RenewChemPhase} \emph{only} defines a phase if \meta{cs} \emph{is}
-already used and issues an error otherwise.  \cs{DeclareChemPhase} does not
-check if the phase command already exists but simply defines it with the new
-meaning.  Unlike the other declaration commands of \chemmacros\
-\cs{NewChemPhase}, \cs{RenewChemPhase} and \cs{DeclareChemPhase} \emph{can
-  only be used in the preamble.}
+% TODO
 
-\begin{example}
-  % preamble:
-  % \NewChemPhase{\aqi}{aq,$\infty$}% aqueous solution at infinite dilution
-  % \NewChemPhase{\cd}{cd}% condensed phase
-  % \NewChemPhase{\lc}{lc}% liquid crystal
-  NaOH\aqi\ \ch{H2O\cd} U\phase{cr} A\lc \par
-  \chemsetup[phases]{pos=sub}
-  NaOH\aqi\ \ch{H2O\cd} U\phase{cr} A\lc
-\end{example}
+\subsection{The \chemmodule*{xfrac} Module}\label{sec:xfrac-module}
 
-\subsection{Language Dependencies}\label{sec:lang-depend}
-For each pahse command a translation into the custom language can be defined.
-If a phase is declared with \cs{NewChemPhase} no translation exists and
-for every \pkg{babel} languuage the literal string is used that was provided
-as a definition.  Let's say you define the phase
-\begin{sourcecode}
-  \NewChemPhase\liquid{l}
-\end{sourcecode}
-and want to add the German translation ``f{}l''.  Then you could do
-\begin{sourcecode}
-  \DeclareTranslation{German}{phase-liquid}{f{}l}
-\end{sourcecode}
-This way, when you use it in a German document using the appropriate
-\pkg{babel} option using \cs*{liquid} would correctly translate.  For this the
-package \pkg{translations} is used.  The \acs{id} always is
-\code{phase-\meta{csname}} where \meta{csname} is the name of the phase
-command you defined without leading backslash.
-
-See section~\ref{sec:languages} for predefined translations.
-
-\section{Newman Projections}\label{sec:newman}
-\chemmacros\ provides a command to draw Newman projections.
+The \chemmodule{xfrac} module loads the package
+\pkg{xfrac}~\cite{bnd:l3packages}.  For the following explanations it will be
+helpful if you know about said package and how it works first.  This module is
+a support module that defines the macro
 \begin{commands}
-  \command{newman}[\oarg{options}\darg{angle}%
-    \Marg{\meta{1},\meta{2},\meta{3},\meta{4},\meta{5},\meta{6}}]
-    Create Newman projections.  This command uses \TikZ\ internally.
-    \meta{angle} rotates the back atoms counter clockwise with respect to the
-    front atoms and is an optional argument.  \meta{1} to \meta{6} are the
-    positions, the first three are the front atoms, the last three the back
-    atoms.
+  \command{chemfrac}[\oarg{type}\marg{numerator}\marg{denominator}]
+    \meta{type} can either be \code{text} or \code{superscript}.
 \end{commands}
+This macro calls a certain instance of the \pkg{xfrac} \code{text} template,
+depending on the option \meta{type} and the current font family.  If used
+\cs{chemfrac} looks if an instance
+\begin{center}
+  \code{chemmacros-frac-\cs*{f@family}-\meta{type}}
+\end{center}
+exists.  If yes this instance is used, if no the instance
+\code{chemmacros-frac-default-\meta{type}} is used.  The \code{default}
+instances are the same as the ones for \code{cmr}.
 
-\begin{example}
-  \newman{} \newman(170){}
-  \newman{1,2,3,4,5,6} \newman{1,2,3} \newman{,,,4,5,6}
-\end{example}
+\begin{table}
+  \centering
+  \newcommand*\showfrac[1]{%
+    \code{#1} &
+    \fontfamily{#1}\selectfont
+    \chemfrac[text]{2}{3} &
+    \fontfamily{#1}\selectfont
+    \chemfrac[superscript]{2}{3}%
+  }
+  \caption{Predefined \chemmodule{xfrac} \code{text} instances.}
+  \label{tab:xfrac}
+  \begin{tabular}{llcc}
+    \toprule
+      \bfseries font family & \bfseries text & \bfseries superscript \\
+    \midrule
+      \showfrac{cmr} \\
+      \showfrac{lmr} \\
+      \showfrac{LinuxLibertineT-TLF} \\
+      \showfrac{LinuxLibertineT-TOsF} \\
+    \bottomrule
+  \end{tabular}
+\end{table}
 
-Several options allow customization:
-\begin{options}
-  \keyval{angle}{angle}\Module{newman}\Default{0}
-    Default angle.
-  \keyval{scale}{factor}\Module{newman}\Default{1}
-    Scale the whole projection by factor \meta{factor}.
-  \keyval{ring}{tikz}\Module{newman}\Default
-    Customize the ring with \TikZ\ keys.
-  \keyval{atoms}{tikz}\Module{newman}\Default
-    Customize the nodes within which the atoms are set with \TikZ\ keys.
-  \keyval{back-atoms}{tikz}\Module{newman}\Default
-    Explicitly customize the nodes of the back atoms with \TikZ\ keys.
-\end{options}
+The \chemmodule{xfrac} module defines instances some font families, they are
+listed and demonstrated in table~\vref{tab:xfrac}.  The \code{superscript}
+type fractions \emph{look} larger than the \code{text} types.  The reason is
+that the \code{superscript} types are typically used with a smaller font size.
+Let's take a look at an example where both instances are used:
+\begin{example}[side-by-side]
+  \chemsetup[redox]{pos=top}
+  \code{superscript}:
+  \ch{"\ox{1/3,I}" {}3+}
 
-\begin{example}
-  \chemsetup[newman]{angle=45} \newman{}
-  \newman[scale=.75,ring={draw=blue,fill=blue!20}]{}
-\end{example}
+  \chemsetup[redox]{pos=side}
+  \code{text}: \ox{1/3,I3+}
 
-\begin{example}
-  \chemsetup[newman]{atoms={draw=red,fill=red!20,inner sep=2pt,rounded corners}}
-  \newman{1,2,3,4,5,6}
-\end{example}
+  \huge
+  \chemsetup[redox]{pos=top}
+  \code{superscript}:
+  \ch{"\ox{1/3,I}" {}3+}
 
-\begin{example}
-  \chemsetup[newman]{
-    atoms = {draw=red,fill=red!20,inner sep=2pt,rounded corners},
-    back-atoms = {draw=blue,fill=blue!20,inner sep=2pt,rounded corners}
-  }
-  \newman{1,2,3,4,5,6} \newman(170){1,2,3,4,5,6}
+  \chemsetup[redox]{pos=side}
+  \code{text}: \ox{1/3,I3+}
 \end{example}
 
-\section{s, p, and Hybrid Orbitals}\label{sec:orbitale}
-
-\chemmacros\ provides the following command to create orbitals:
-\begin{commands}
-  \command{orbital}[\oarg{options}\marg{type}]
-    Draw an orbital shape of type \meta{type}.  This command uses \TikZ\
-    internally.
-\end{commands}
+If you define instances for other families please feel free to submit them to
+me (see section~\vref{sec:submitting-module}) so they can be added to the
+\chemmodule{xfrac} module.
 
-There are the following types available for \meta{type}:
-\begin{itemize}
-  \item[]
-    \code{s} \quad
-    \code{p} \quad
-    \code{sp} \quad
-    \code{sp2} \quad
-    \code{sp3}
-\end{itemize}
+\appendix
+\part{Appendix}
+\section{Own Modules}\label{sec:own-modules}
+\subsection{How To}
 
-\begin{example}
-  \orbital{s} \orbital{p} \orbital{sp} \orbital{sp2} \orbital{sp3}
-\end{example}
+If you have additional functionality which you think might be useful as a
+\chemmacros\ module then you can easily write one yourself.  The module must
+be a file in a path where \TeX\ can find it following a certain naming
+scheme.  The file for a module \chemmodule*{foo} must be named
+\code{chemmacros.module.foo.code.tex}.
 
-Depending on the type you have different options to modify the orbitals:
-\begin{options}
-  \keychoice{phase}{\default{+},-}\Module{orbital}\Default{+}
-    changes the phase of the orbital (all types)
-  \keyval{scale}{factor}\Module{orbital}\Default{1}
-    changes the size of the orbital (all types)
-  \keyval{color}{color}\Module{orbital}\Default{black}
-    changes the color of the orbital (all types)
-  \keyval{angle}{angle}\Module{orbital}\Default{0}
-    rotates the orbitals with a p contribution counter clockwise (all types
-    except \code{s})
-  \keybool{half}\Module{orbital}\Default{false}
-    displays only half an orbital (only \code{p})
-\end{options}
+The first line in the file then should look similar to this:
+\begin{sourcecode}
+  \ChemModule{foo}{2015/07/14 description of foo}
+\end{sourcecode}
+This registers module \chemmodule*{foo} which means \chemmacros\ will accept
+this file as a valid module.
 
-\begin{example}
-  \orbital{s} \orbital[phase=-]{s} 
-  \orbital{p} \orbital[phase=-]{p}
-  \orbital{sp3} \orbital[phase=-]{sp3}
- 
-  \orbital[angle=0]{p} \orbital[color=red!50]{p}
-  \orbital[angle=135,scale=1.5]{p} \orbital[half]{p}
-\end{example}
+Since \chemmacros\ is written using expl3 \cs{ChemModule} starts an expl3
+programming environment.  If you don't want that but rather want to write your
+module using traditional \LaTeXe\ methods then use the starred variant:
+\begin{sourcecode}
+  \ChemModule*{foo}{2015/07/14 description of foo}
+\end{sourcecode}
+In both variants \code{@} has category code~11 (letter).
 
-Additionally there are two options, with which the \TikZ\ behaviour can be
-changed.
-\begin{options}
-  \keybool{overlay}\Module{orbital}
-    The orbital \enquote{doesn't need space}; it is displayed with the \TikZ\
-    option \code{overlay}.
-  \keyval{opacity}{num}\Module{orbital}
-    The orbital becomes transparent; \meta{value} can have values between
-    \code{1} (fully opaque) to \code{0} (invisible).
-\end{options}
-\begin{example}
-  \vspace{7mm}
-  \chemsetup[orbital]{
-    overlay,
-    p/color = black!70
-  }
-  \setbondoffset{0pt}
-  \chemfig{
-    ?\orbital{p}
-    -[,1.3]{\orbital[phase=-]{p}}
-    -[:30,1.1]\orbital{p}
-    -[:150,.9]{\orbital[phase=-]{p}}
-    -[4,1.3]\orbital{p}
-    -[:-150,1.1]{\orbital[phase=-]{p}}?
-  }
-  \vspace{7mm}
-\end{example}
+You should be aware that your module \emph{will not be loaded} with
+\verbcode+\usechemmodule{all}+! The pseudo-module \chemmodule{all} contains a
+manually maintained list of the modules that are loaded by it.
 
-\begin{example}
-  \vspace{7mm}
-  \setbondoffset{0pt}
-  \chemsetup[orbital]{
-    overlay ,
-    opacity = .75 ,
-    p/scale = 1.6 ,
-    s/color = blue!50 ,
-    s/scale = 1.6
-  }
-  \chemfig{
-    \orbital{s}
-    -[:-20]{\orbital[scale=2]{p}}
-           {\orbital[half,angle=0]{p}}
-           {\orbital[angle=170,half]{p}}
-           {\orbital[angle=-150,half]{p}}
-    (-[:-150]\orbital{s})-\orbital{s}
+If you decide to write your module \chemmodule*{foo} using expl3 and add
+options you want to be able to set using
+\cs{chemsetup}\Oarg{foo}\marg{options} please make sure you define them the
+following way:
+\begin{sourcecode}
+  \keys_define:nn {chemmacros/foo} {
+    ...
   }
-  \vspace{1cm}
-\end{example}
+\end{sourcecode}
+Also (especially if you consider submitting the module, see
+section~\vref{sec:submitting-module}) please follow the expl3 naming
+conventions for variables and functions, \ie, use \code{chemmacros} as expl3
+module name:
+\begin{sourcecode}
+  \tl_new:N \l__chemmacros_my_internal_variable_tl
+  \tl_new:N \l_chemmacros_my_public_variable_tl
+  \cs_new:Npn \__chemmacros_my_internal_function:n #1 { ... }
+  \cs_new_protected:Npn \chemmacros_my_public_function:n #1 { ... }
+  \NewDocumentCommand \publicfunction {m}
+    { \chemmacros_my_public_function:n {#1} }
+\end{sourcecode}
+You will find more details on the naming conventions in \code{interface3.pdf}
+which most likely is available on your system:
+\begin{bash}
+  texdoc interface3
+\end{bash}
 
-\appendix
-\part{Appendix}
-\addsec{Suggestions and Bug Reports}
+\subsection{Submitting a Module}\label{sec:submitting-module}
 
-Feedback on \chemmacros{} (and also on \chemformula, \chemgreek, and
-\ghsystem) is highly appreciated and welcome!
+If you have written a module and feel it might be useful for other users
+please feel free to contact me and submit the module.  I will surely take at
+look at both functionality and code and if I feel that it adds value to
+\chemmacros\ I will add it to the package.  Requirement for this is that the
+module is licensed with the \LPPL\ (v1.3 or later) and that I take over
+maintenance (according to the \enquote{maintainer} status of the \lppl).
 
-If you have suggestions for macros, missing features \etc, please don't
-hesitate to contact me.  If you recognize any errors, be it chemical ones,
-wrong documentation and the like, I'd be grateful about a short
-email\footnote{\href{mailto:contact@mychemistry.eu}{contact@mychemistry.eu}}.
+Please do \emph{not} submit your module via pull request but send me the files
+directly.  In the best case you also have a short piece of documentation.
 
-If you find any bugs, it would be best, if you'd send me a minimal example,
-with which I can reproduce the bug.  You can also submit an issue on
-\url{https://github.com/cgnieder/chemmacros/} instead.
+\section{Suggestions, Bug Reports, Support}\label{sec:sugg-bug-reports}
 
-Many thanks to all the people who already provided me with feedback,
-especially (in alphabetical order):
+\paragraph{Support}
+If you need support or help with anything regarding \chemmacros\ please use
+the usual support forums
+\begin{itemize}
+  \item \url{http://www.golatex.de/} or
+  \item \url{http://texwelt.de/wissen/} if you speak German,
+  \item \url{http://www.latex-community.org/forum/} or
+  \item \url{http://tex.stackexchange.com/} if you speak English
+\end{itemize}
+or go the \emph{dedicated support forum}
 \begin{itemize}
-  \item Peter Cao
-  \item Ignacio Fernández Galván for his translation of the hazard and
-    precautionary statements of the \ghsystem{} package into Spanish
-  \item Christina Lüdigk
-  \item Dr.~Paul King
-  \item Jonas Rivetti (Special thanks for his translation of the hazard and
-    precautionary statements of the \ghsystem{} package into Italian!)
-  \item Christoph Schäfer
-  \item Timo Stein
-  \item Herbert Voß
+  \item \url{http://www.mychemistry.eu/forums/forum/chemmacros/}
 \end{itemize}
+where you can be sure that I will see the question.
+  
+\paragraph{Suggestions}
+If you have any suggestions on how \chemmacros\ could be improved, adding
+missing features \etc, please feel free to contact me via
+\email{contact@mychemistry.eu}.
+
+\paragraph{Bug reports}
+If you find any bugs, \ie, errors (something not working as described,
+conflicts with other packages, \ldots) then please go to
+\url{https://github.com/cgnieder/chemmacros/issues/} and open a new issue
+describing the error including a minimal working example.
 
 \end{document}
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.acid-base.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.acid-base.code.tex
new file mode 100644
index 00000000000..2d0346d5b79
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.acid-base.code.tex
@@ -0,0 +1,131 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `acid-base'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{acid-base}{2015/06/09 acid/base}
+
+\chemmacros_load_modules:n {charges}
+
+% --------------------------------------------------------------------------
+\tl_new:N  \l__chemmacros_k_acid_tl
+\tl_new:N  \l__chemmacros_k_base_tl
+\tl_new:N  \l__chemmacros_k_water_tl
+
+\tl_set:Nn \l__chemmacros_k_acid_tl  { \chemmacros_translate:n {K-acid} }
+\tl_set:Nn \l__chemmacros_k_base_tl  { \chemmacros_translate:n {K-base} }
+\tl_set:Nn \l__chemmacros_k_water_tl { \chemmacros_translate:n {K-water} }
+
+\keys_define:nn {chemmacros/acid-base}
+  {
+    p-style           .choice: ,
+    p-style / slanted .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textsl ,
+    p-style / italics .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textit ,
+    p-style / upright .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textup ,
+    K-acid            .tl_set:N = \l__chemmacros_k_acid_tl ,
+    K-base            .tl_set:N = \l__chemmacros_k_base_tl ,
+    K-water           .tl_set:N = \l__chemmacros_k_water_tl
+  }
+
+\cs_new_eq:NN \chemmacros_p_style:n \textup
+
+\cs_new_protected:Npn \Ka
+  {
+    \ensuremath
+      {
+        \chemmacros_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_acid_tl }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \Kb
+  {
+    \ensuremath
+      {
+        \chemmacros_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_base_tl }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \Kw
+  {
+    \ensuremath
+      {
+        \chemmacros_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_water_tl }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_p:n #1
+  {
+    \group_begin:
+      \mbox
+        {
+          \chemmacros_p_style:n { p }
+          \ensuremath { #1 }
+        }
+    \group_end:
+  }
+
+\NewDocumentCommand \p { m }
+  { \chemmacros_p:n { #1 } }
+
+\cs_new_protected:Npn \pH
+  { \chemmacros_p:n { \chemmacros_chemformula:n {H} } }
+
+\cs_new_protected:Npn \pOH
+  { \chemmacros_p:n { \chemmacros_chemformula:n {OH} } }
+
+\NewDocumentCommand \pKa { o }
+  {
+    \chemmacros_p:n
+      {
+        \Ka \IfNoValueF { #1 }
+          { {} \c_math_subscript_token { \chemmacros_bold:n { #1 } } }
+      }
+  }
+
+\NewDocumentCommand \pKb { o }
+  {
+    \chemmacros_p:n
+      {
+        \Kb \IfNoValueF { #1 }
+          { {} \c_math_subscript_token { \chemmacros_bold:n { #1 } } }
+      }
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.all.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.all.code.tex
new file mode 100644
index 00000000000..53226a9aa90
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.all.code.tex
@@ -0,0 +1,56 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `all'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{all}{2015/06/09 load all libraries}
+
+\chemmacros_load_modules:n
+  {
+     base ,
+     lang ,
+     greek ,
+     chemformula ,
+     tikz ,
+     acid-base ,
+     charges ,
+     isotopes ,
+     mechanisms ,
+     newman ,
+     nomenclature ,
+     orbital ,
+     particles ,
+     phases ,
+     reactions ,
+     redox ,
+     scheme ,
+     spectroscopy ,
+     symbols ,
+     thermodynamics ,
+     units ,
+     xfrac
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.base.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.base.code.tex
new file mode 100644
index 00000000000..eab20de2076
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.base.code.tex
@@ -0,0 +1,264 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `base'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{base}{2015/07/25 basic chemmacros module}
+
+% --------------------------------------------------------------------------
+\msg_new:nnn {chemmacros} {command-deprecated}
+  {
+    The~ command~ \token_to_str:N #1 \c_space_tl is~ deprecated.~ Use~
+    \token_to_str:N #2 \c_space_tl instead.
+  }
+
+% define a deprecated command with hints to the corresponding new one:
+\cs_new_protected:Npn \chemmacros_define_deprecated:NN #1#2
+  {
+    \cs_set_protected:Npn #1
+      {
+        \msg_warning:nnnn {chemmacros} {command-deprecated} {#1} {#2}
+        #2
+      }
+  }
+
+\NewDocumentCommand \DeclareChemDeprecated {mm}
+  { \chemmacros_define_deprecated:NN #1 #2 }
+
+% --------------------------------------------------------------------------
+% define a macro set:
+% \NewChem... \RenewChem... \DeclareChem... \ProvideChem...
+% #1: macro names
+% #2: arg spec
+% #3: internal command call
+\cs_new_protected:Npn \chemmacros_new_macroset:nnn #1#2#3
+  {
+    \exp_args:Nc \NewDocumentCommand {NewChem#1} {#2}
+      {
+        \cs_if_free:NTF ##1
+          { #3 }
+          { \msg_error:nnn {chemmacros} {new-#1} {##1} }
+      }
+    \exp_args:Nc \NewDocumentCommand {RenewChem#1} {#2}
+      {
+        \cs_if_free:NTF ##1
+          { \msg_error:nnn {chemmacros} {renew-#1} {##1} }
+          { #3 }
+      }
+    \exp_args:Nc \NewDocumentCommand {DeclareChem#1} {#2} {#3}
+    \exp_args:Nc \NewDocumentCommand {ProvideChem#1} {#2}
+      { \cs_if_free:NT ##1 { #3 } }
+    \msg_new:nnn {chemmacros} {new-#1}
+      {
+        You've~ tried~ to~ define~ a~ #1~ with~ \token_to_str:N
+        \NewChem #1 ,~ but~ the~ command~ sequence~ \token_to_str:N ##1
+        \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+      }
+    \msg_new:nnn {chemmacros} {renew-#1}
+      {
+        You've~ tried~ to~ renew~ the~ #1~ \token_to_str:N ##1 ,~ but~
+        it~ doesn't~ exist.
+      }
+  }
+
+\NewDocumentCommand \NewChemMacroset {mmm}
+  { \cs_new_protected:Npn \chemmacros_new_macroset:nnn {#1} {#2} {#3} }
+
+\cs_new_protected:Npn \chemmacros_new_environment_macroset:nnn #1#2#3
+  {
+    \exp_args:Nc \NewDocumentCommand {NewChem#1} {#2}
+      {
+        \bool_if:nTF { \cs_if_free_p:c {##1} && \cs_if_free_p:c {end##1} }
+          { #3 }
+          { \msg_error:nnn {chemmacros} {new-#1} {##1} }
+      }
+    \exp_args:Nc \NewDocumentCommand {RenewChem#1} {#2}
+      {
+        \bool_if:nTF { \cs_if_free_p:c {##1} || \cs_if_free_p:c {end##1} }
+          { \msg_error:nnn {chemmacros} {renew-#1} {##1} }
+          { #3 }
+      }
+    \exp_args:Nc \NewDocumentCommand {DeclareChem#1} {#2} {#3}
+    \exp_args:Nc \NewDocumentCommand {ProvideChem#1} {#2}
+      {
+        \bool_if:nT { \cs_if_free_p:c {##1} && \cs_if_free_p:c {end##1} }
+          { #3 }
+      }
+    \msg_new:nnn {chemmacros} {new-#1}
+      {
+        You've~ tried~ to~ define~ a~ #1~ with~ \token_to_str:N
+        \NewChem #1 ,~ but~ the~ command~ sequence~ \exp_not:c {##1}
+        \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+      }
+    \msg_new:nnn {chemmacros} {renew-#1}
+      { You've~ tried~ to~ renew~ the~ #1~ ##1,~ but~ it~ doesn't~ exist. }
+  }
+  
+% --------------------------------------------------------------------------
+% basic tools:
+\cs_new:Npn \chemmacros_remove_backslash:N #1
+  { \exp_after:wN \use_none:n \token_to_str:N #1 }
+
+\cs_new_eq:NN \chemmacros_ignore_spaces: \tex_ignorespaces:D
+
+\cs_new_protected:Npn \chemmacros_leave_vmode: { \hbox_unpack:N \c_empty_box }
+\cs_new_protected:Npn \chemmacros_nobreak:     { \tex_penalty:D \c_ten_thousand }
+\cs_new_protected:Npn \chemmacros_allow_break: { \tex_penalty:D \c_zero }
+\cs_new_protected:Npn \chemmacros_skip_nobreak:N #1
+  {
+    \chemmacros_nobreak:
+    \skip_horizontal:N #1
+    \chemmacros_nobreak:
+  }
+
+% do I use those at all?
+\prg_new_conditional:Npnn \chemmacros_tex_if:nn #1#2 {p,T,F,TF}
+  { \use:c { if #1 } #2 \prg_return_true: \else: \prg_return_false: \fi: }
+
+\prg_new_conditional:Npnn \chemmacros_latex_if:n #1 {p,T,F,TF}
+  { #1 { \prg_return_true: } { \prg_return_false: } }
+
+% this is used at least in the `isotope' module
+\prg_new_conditional:Npnn \chemmacros_if_is_int:n #1 {p,T,F,TF}
+  {
+    \if_charcode:w ! \if_int_compare:w 9 < 1#1 ! \else: _ \fi:
+      \prg_return_true:
+    \else:
+      \prg_return_false:
+    \fi:
+  }
+
+\prg_new_conditional:Npnn \chemmacros_if_loaded:nn #1#2 {p,T,F,TF}
+  {
+    \use:c {chemmacros_if_#1_loaded:nTF} {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+  
+\prg_new_conditional:Npnn \chemmacros_if_package_loaded:n #1 {p,T,F,TF}
+  {
+    \cs_if_exist:cTF {ver@#1.sty}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \chemmacros_if_class_loaded:n #1 {p,T,F,TF}
+  {
+    \cs_if_exist:cTF {ver@#1.cls}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% --------------------------------------------------------------------------
+% some checks at begin document:
+\bool_new:N \l__chemmacros_in_document_bool
+\bool_new:N \l__chemmacros_chemstyle_bool
+
+\AtBeginDocument
+  {
+    \bool_set_true:N \l__chemmacros_in_document_bool
+    \@ifpackageloaded { chemstyle }
+      { \bool_set_true:N \l__chemmacros_chemstyle_bool }
+      { \bool_set_false:N \l__chemmacros_chemstyle_bool }
+  }
+
+% --------------------------------------------------------------------------
+% detection and handling of bold face:
+\RequirePackage{bm}
+
+\prg_new_protected_conditional:Npnn \chemmacros_if_bold: {T,F,TF}
+  {
+    \seq_if_in:NVTF \l__chemmacros_if_bf_seq \f@series
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\seq_new:N  \l__chemmacros_if_bf_seq
+
+\seq_set_split:Nnn \l__chemmacros_if_bf_seq { , }
+  {
+    b , bc , bm , bx , bux ,
+    eb , ebc , ebx , mb ,
+    sb , sbc , sbx ,
+    ub , ubc , ubx
+  }
+
+\cs_new_protected:Npn \chemmacros_bold:n #1
+  {
+    \chemmacros_if_bold:TF
+      {
+        \mode_if_math:TF
+          { \bm {#1} }
+          { \textbf {#1} }
+      }
+      {#1}
+  }
+
+\cs_new_protected:Npn \chemmacros_detect_bold:n
+  { \error \chemmacros_bold:n }
+
+% --------------------------------------------------------------------------
+\RequirePackage{amstext}
+
+\cs_new_protected:Npn \chemmacros_text:n #1
+  { \mode_if_math:TF { \text {#1} } {#1} }
+\cs_generate_variant:Nn \chemmacros_text:n { V }
+
+\cs_new_protected:Npn \chemmacros_math:n #1
+  { \chemmacros_text:n { \c_math_toggle_token #1 \c_math_toggle_token } }
+\cs_generate_variant:Nn \chemmacros_math:n { V }
+
+% --------------------------------------------------------------------------
+% a setup command:
+\NewDocumentCommand \chemsetup { o m }
+  {
+    \IfNoValueTF {#1}
+      { \keys_set:nn {chemmacros} {#2} }
+      { \keys_set:nn { chemmacros / #1 } {#2} }
+  }
+
+\keys_define:nn {chemmacros}
+  { modules .code:n = \chemmacros_load_modules:n {#1} }
+
+% --------------------------------------------------------------------------
+
+% load package #1 and add its options to chemmacros
+%   this requires that package #1 defines its options with l3keys using its
+%   name as module
+\cs_new_protected:Npn \chemmacros_integrate_package:nn #1#2
+  {
+    \tl_if_blank:nTF {#2}
+      { \RequirePackage {#1} }
+      { \RequirePackage {#1} [#2] }
+    \keys_define:nn {chemmacros}
+      {
+        #1 .choice: ,
+        #1 / unknown .code:n =
+          \keys_set:no {#1} { \l_keys_key_tl = ##1 }
+      }
+  }
+
+% --------------------------------------------------------------------------
+
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.charges.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.charges.code.tex
new file mode 100644
index 00000000000..36a190a85ed
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.charges.code.tex
@@ -0,0 +1,152 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `charges'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{charges}{2015/07/30 charges}
+
+\chemmacros_load_module:n {chemformula}
+
+% --------------------------------------------------------------------------
+% circled charge signs: they are defined in the `chemformula' package:
+% use directly:
+\cs_new_protected:Npn \fplus  { { \chemformula_fplus:  } }
+\cs_new_protected:Npn \fminus { { \chemformula_fminus: } }
+
+% change output depending on circled-option
+\bool_new:N      \l__chemmacros_circled_bool
+\bool_set_true:N \l__chemmacros_circled_bool
+\bool_new:N      \l__chemmacros_circled_formal_bool
+\bool_set_true:N \l__chemmacros_circled_formal_bool
+\bool_new:N      \l__chemmacros_circled_chem_bool
+\bool_set_true:N \l__chemmacros_circled_chem_bool
+
+
+\keys_define:nn { chemmacros / charges }
+  {
+    circletype         .choice: ,
+    circletype / math  .code:n  =
+      {
+        \bool_set_false:N \l__chemmacros_circled_chem_bool
+        \bool_set_false:N \l_chemformula_formal_chem_bool
+      } ,
+    circletype / chem  .code:n  =
+      {
+        \bool_set_true:N \l__chemmacros_circled_chem_bool
+        \bool_set_true:N \l_chemformula_formal_chem_bool
+      } ,
+    circletype         .value_required:n = true ,
+    circled            .choice: ,
+    circled / none     .code:n =
+      {
+        \bool_set_false:N \l__chemmacros_circled_bool
+        \bool_set_false:N \l__chemmacros_circled_formal_bool
+        \bool_set_false:N \l_chemformula_formal_charges_bool
+      } ,
+    circled / formal   .code:n =
+      {
+        \bool_set_true:N \l__chemmacros_circled_bool
+        \bool_set_true:N \l__chemmacros_circled_formal_bool
+        \bool_set_false:N \l_chemformula_formal_charges_bool
+      } ,
+    circled / all      .code:n =
+      {
+        \bool_set_true:N \l__chemmacros_circled_bool
+        \bool_set_false:N \l__chemmacros_circled_formal_bool
+        \bool_set_true:N \l_chemformula_formal_charges_bool
+      } ,
+    circled            .default:n  = all
+  }
+
+\cs_new_protected:Npn \chemmacros_plus:  { \chemformula_plus: }
+\cs_new_protected:Npn \chemmacros_minus: { \chemformula_minus: }
+
+\cs_new_protected:Npn \chemmacros_formal_plus: { \chemformula_formal_plus: }
+\cs_new_protected:Npn \chemmacros_formal_minus: { \chemformula_formal_minus: }
+
+\cs_new_protected:Npn \chemmacros_charge:n #1
+  { \chemmacros_chemformula:n { {}^{#1} } }
+
+\cs_new_protected:Npn \chemmacros_new_charge_command:Nn #1#2
+  {
+    \DeclareDocumentCommand #1 {o}
+      {
+        \IfNoValueTF {##1}
+          { \chemmacros_charge:n {#2} }
+          { \chemmacros_charge:n {##1#2} }
+      }
+  }
+
+\tl_new:N  \l__chemmacros_partial_charge_format_tl
+\tl_set:Nn \l__chemmacros_partial_charge_format_tl { \tiny }
+
+\cs_new_protected:Npn \chemmacros_new_partial_charge_command:Nn #1#2
+  {
+    \cs_new_protected:Npn #1
+      {
+        \mbox {
+          \l__chemmacros_partial_charge_format_tl
+          \c_math_toggle_token \delta #2 \c_math_toggle_token
+        }
+      }
+  }
+
+\chemmacros_new_macroset:nnn {Charge} {mm}
+  { \chemmacros_new_charge_command:Nn #1 {#2} }
+  
+\chemmacros_new_macroset:nnn {PartialCharge} {mm}
+  { \chemmacros_new_partial_charge_command:Nn #1 {#2} }
+
+\cs_new_protected:Npn \scrm
+  { \ensuremath { \scriptstyle \chemmacros_minus: } }
+\cs_new_protected:Npn \scrp
+  { \ensuremath { \scriptstyle \chemmacros_plus: } }
+\cs_new_protected:Npn \fscrm
+  { \ensuremath { \scriptstyle \chemmacros_formal_minus: } }
+\cs_new_protected:Npn \fscrp
+  { \ensuremath { \scriptstyle \chemmacros_formal_plus: } }
+\cs_new_protected:Npn \fsscrm
+  { \ensuremath { \scriptscriptstyle \chemmacros_formal_minus: } }
+\cs_new_protected:Npn \fsscrp
+  { \ensuremath { \scriptscriptstyle \chemmacros_formal_plus: } }
+
+\keys_define:nn {chemmacros/charges}
+  {
+    partial-format .tl_set:N = \l__chemmacros_partial_charge_format_tl
+  }
+
+% --------------------------------------------------------------------------
+\NewChemCharge \mch  { \chemmacros_minus: }
+\NewChemCharge \pch  { \chemmacros_plus: }
+\NewChemCharge \fmch { \chemmacros_formal_minus: }
+\NewChemCharge \fpch { \chemmacros_formal_plus: }
+
+% partial charges:
+\NewChemPartialCharge \delm  { \chemmacros_minus: }
+\NewChemPartialCharge \delp  { \chemmacros_plus: }
+\NewChemPartialCharge \fdelm { \chemmacros_formal_minus: }
+\NewChemPartialCharge \fdelp { \chemmacros_formal_plus: }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.chemformula.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.chemformula.code.tex
new file mode 100644
index 00000000000..56c469f6245
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.chemformula.code.tex
@@ -0,0 +1,42 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `chemformula'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{chemformula}{2015/07/25 chemformula integration}
+
+\chemmacros_load_module:n {charges}
+
+\chemmacros_integrate_package:nn {chemformula} {2015/08/19}
+
+\RequirePackage{amstext}
+
+% --------------------------------------------------------------------------
+% let's make use of `chemformula' inside some of `chemmacros' commands:
+\cs_new_protected:Npn \chemmacros_chemformula:n #1
+  { \chemformula_chcpd:nn {} {#1} }
+\cs_generate_variant:Nn \chemmacros_chemformula:n { x,V }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.greek.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.greek.code.tex
new file mode 100644
index 00000000000..72180d595af
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.greek.code.tex
@@ -0,0 +1,72 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `greek'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{greek}{2015/06/09 upright greek symbols}
+
+\RequirePackage{chemgreek}[2015/04/09]
+
+\msg_new:nnn {chemmacros} {no-greek}
+  {
+    You~ haven't~ loaded~ any~ package~ for~ upright~ Greek~ letters~ or~ no~
+    unique~ choice~ was~ possible.~ Either~ load~ one~ of~ packages~
+    specified~ in~ the~ manual~ or~ select~ a~ chemgreek~ mapping~ manually.
+  }
+
+\msg_new:nnn {chemmacros} {greek-undefined}
+  {
+    The~ chemgreek~ mapping~ `#1'~ you~ chose~ \msg_line_context: \c_space_tl
+    is~ not~ defined.~ Please~ choose~ another~ one.
+  }
+
+% chemgreek selects a mapping if an unambiguous choice is possible, otherwise
+% selects `default'. Warn the user in this case:
+\AtBeginDocument{
+  \bool_if:nT
+    {
+      \chemgreek_if_mapping_active_p:n {default} ||
+      \chemgreek_if_mapping_active_p:n {var-default}
+    }
+    { \msg_warning:nn {chemmacros} {no-greek} }
+}
+
+% an option for manual selection:
+\keys_define:nn {chemmacros}
+  {
+    greek .code:n = \chemmacros_choose_chemgreek_mapping:n {#1}
+  }
+
+\cs_new_protected:Npn \chemmacros_choose_chemgreek_mapping:n #1
+  {
+    \chemgreek_if_mapping_exists:nTF {#1}
+      {
+        \chemgreek_load_mapping_package:n {#1}
+        \chemgreek_activate_mapping:n {#1}
+      }
+      { \msg_warning:nnn {chemmacros} {greek-undefined} {#1} }
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.isotopes.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.isotopes.code.tex
new file mode 100644
index 00000000000..6a788d8373c
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.isotopes.code.tex
@@ -0,0 +1,235 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `isotopes'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{isotopes}{2015/07/22 a macro to easily print element isotopes}
+
+\RequirePackage{elements}
+
+\msg_new:nnn {chemmacros} {no-isotope}
+  { The~ isotope~ #2~ is~ not~ defined~ for~ element~ #1. }
+
+% --------------------------------------------------------------------------
+\tl_new:N  \l__chemmacros_isotope_tl
+\tl_new:N  \l__chemmacros_isotope_list_tl
+\seq_new:N \l__chemmacros_isotope_seq
+\seq_new:N \l__chemmacros_check_isotopes_seq
+
+% #1: atomic number|element symbol|element name
+% #2: tokenlist variable
+\cs_new_protected:Npn \chemmacros_get_atom_number:nN #1#2
+  {
+    \chemmacros_if_is_int:nTF {#1}
+      { \tl_set:Nn #2 {#1} }
+      {
+        \cs_if_exist:cTF { @elements@atom@number@ \str_lower_case:n {#1} }
+          { \tl_set:Nx #2 { \use:c { @elements@atom@number@ \str_lower_case:n {#1} } } }
+          { \tl_set:Nx #2 { \use:c { @elements@atom@name@num@ \str_lower_case:n {#1} } } }
+      }
+  }
+\cs_generate_variant:Nn \chemmacros_get_atom_number:nN { V }
+
+% #1: atomic number|element symbol|element name
+% #2: tl to store the result in
+\cs_new_protected:Npn \chemmacros_get_isotope_list:nN #1#2
+  {
+    \chemmacros_get_atom_number:nN {#1} \l__chemmacros_isotope_tl
+    \tl_set:Nx #2
+      {
+        \use:c
+          {
+            @elements@atom@isotopes@
+            \int_to_roman:n {\l__chemmacros_isotope_tl}
+          }
+      }
+  }
+
+% #1: atomic number|element symbol|element name
+% #2: tokenlist variable
+\cs_new_protected:Npn \chemmacros_get_element_symbol:nN #1#2
+  {
+    \chemmacros_get_atom_number:nN {#1} \l__chemmacros_isotope_tl
+    \tl_set:Nx #2
+      {
+        \use:c
+          {
+            @elements@atom@symbol@num@
+            \int_to_roman:n {\l__chemmacros_isotope_tl}
+          }
+      }
+  }
+
+% #1: atomic number|element symbol|element name
+% #2: isotope number
+\prg_new_protected_conditional:Npnn \chemmacros_check_isotope:nn #1#2 {T,F,TF}
+  {
+    \chemmacros_get_isotopes:nN {#1} \l__chemmacros_check_isotopes_seq
+    \seq_if_in:NnTF \l__chemmacros_check_isotopes_seq {#2}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+\cs_generate_variant:Nn \chemmacros_check_isotope:nnF { V }
+
+% #1: atomic number|element symbol|element name
+% #2: tl to store the result in
+\cs_new_protected:Npn \chemmacros_get_main_isotope:nN #1#2
+  {
+    \chemmacros_get_isotope_list:nN {#1} \l__chemmacros_isotope_list_tl
+    \seq_set_split:NnV \l__chemmacros_isotope_seq {,} \l__chemmacros_isotope_list_tl
+    \seq_map_inline:Nn \l__chemmacros_isotope_seq
+      {
+        \chemmacros_read_isotope:nNN {##1}
+          \l__chemmacros_tmpa_bool
+          #2
+        \bool_if:NT \l__chemmacros_tmpa_bool
+          { \seq_map_break: }
+      }
+  }
+\cs_generate_variant:Nn \chemmacros_get_main_isotope:nN { V }
+
+% #1: atomic number|element symbol|element name
+% #2: seq to store the results in
+\cs_new_protected:Npn \chemmacros_get_isotopes:nN #1#2
+  {
+    \seq_clear:N #2
+    \chemmacros_get_isotope_list:nN {#1} \l__chemmacros_tmpa_tl
+    \seq_set_split:NnV \l__chemmacros_isotope_seq {,} \l__chemmacros_tmpa_tl
+    \seq_map_inline:Nn \l__chemmacros_isotope_seq
+      {
+        \chemmacros_read_isotope:nNN {##1}
+          \l__chemmacros_tmpa_bool
+          \l__chemmacros_tmpa_tl
+        \seq_put_right:NV #2 \l__chemmacros_tmpa_tl
+      }
+  }
+
+% #1: boolean variable
+% #2: tokenlist variable
+% #3: isotope list entry
+\cs_new_protected:Npn \chemmacros_read_isotope:nNN #1#2#3
+  { \__chemmacros_read_isotope:NNw #2#3 !#1!! \q_stop }
+
+% \__chemmacros_read_isotope:NNw N N !!1!! \q_stop
+% \__chemmacros_read_isotope:NNw N N !1!! \q_stop
+\cs_new_protected:Npn \__chemmacros_read_isotope:NNw #1#2#3!#4!#5!#6 \q_stop
+  {
+    \tl_if_blank:nTF {#5}
+      {
+        \tl_set:Nn #2 {#4}
+        \bool_set_false:N #1
+      }
+      {
+        \tl_set:Nn #2 {#5}
+        \bool_set_true:N #1
+      }
+  }
+
+% --------------------------------------------------------------------------
+% #1: boolean: hide atomic number?
+% #2: nucleons, element symbol
+\cs_new_protected:Npn \chemmacros_isotope:nn #1#2
+  { \__chemmacros_isotope:nww {#1} #2,, \q_stop }
+
+\cs_new_protected:Npn \__chemmacros_isotope:nww #1#2,#3,#4 \q_stop
+  {
+    \tl_if_blank:nTF {#3}
+      {
+        \chemmacros_get_element_symbol:nN {#2} \l__chemmacros_tmpa_tl
+        \chemmacros_get_main_isotope:nN {#2} \l__chemmacros_tmpb_tl
+        \chemmacros_get_atom_number:nN {#2} \l__chemmacros_tmpc_tl
+        \bool_if:nTF {#1}
+          {
+            \chemmacros_isotope_write:VnV
+              \l__chemmacros_tmpb_tl
+              { }
+              \l__chemmacros_tmpa_tl
+          }
+          {
+            \chemmacros_isotope_write:VVV
+              \l__chemmacros_tmpb_tl
+              \l__chemmacros_tmpc_tl
+              \l__chemmacros_tmpa_tl
+          }
+      }
+      {
+        \chemmacros_get_element_symbol:nN {#3} \l__chemmacros_tmpa_tl
+        \chemmacros_get_atom_number:nN {#3} \l__chemmacros_tmpb_tl
+        \chemmacros_check_isotope:VnF
+          \l__chemmacros_tmpa_tl
+          {#2}
+          {
+            \chemmacros_get_element_symbol:nN {#3} \l__chemmacros_tmpa_tl
+            \msg_warning:nnVn {chemmacros} {no-isotope}
+              \l__chemmacros_tmpa_tl
+              {#2}
+          }
+        \chemmacros_get_element_symbol:nN {#3} \l__chemmacros_tmpa_tl
+        \bool_if:nTF {#1}
+          { \chemmacros_isotope_write:nnV {#2} { } \l__chemmacros_tmpa_tl }
+          {
+            \chemmacros_isotope_write:nVV {#2}
+              \l__chemmacros_tmpb_tl
+              \l__chemmacros_tmpa_tl
+          }
+      }
+  }
+
+\bool_new:N \l__chemmacros_isotope_super_bool
+\tl_new:N \l__chemmacros_isotope_side_connect_tl
+
+\keys_define:nn {chemmacros/isotopes}
+  {
+    format .choice: ,
+    format / super .code:n  =
+      \bool_set_true:N \l__chemmacros_isotope_super_bool ,
+    format / side .code:n   =
+      \bool_set_false:N \l__chemmacros_isotope_super_bool ,
+    format .initial:n       = super ,
+    side-connect .tl_set:N  = \l__chemmacros_isotope_side_connect_tl ,
+    side-connect .initial:n = -
+  }
+
+% #1: nucleons
+% #2: atomic number
+% #3: element symbol
+\cs_new_protected:Npn \chemmacros_isotope_write:nnn #1#2#3
+  {
+    \bool_if:NTF \l__chemmacros_isotope_super_bool
+      { \chemmacros_chemformula:n { ^{#1}_{#2}#3 } }
+      {
+        \chemmacros_chemformula:n {#3}
+        \tl_use:N \l__chemmacros_isotope_side_connect_tl
+        #1
+      }
+  }
+\cs_generate_variant:Nn \chemmacros_isotope_write:nnn { VnV , VVV , nnV , nVV }
+
+% TODO: option for the layout of the written isotope: ^{12}_6C vs C-12
+
+\NewDocumentCommand \isotope { sm }
+  { \chemmacros_isotope:nn {#1} {#2} }
+  
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.lang.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.lang.code.tex
new file mode 100644
index 00000000000..45d7d267abc
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.lang.code.tex
@@ -0,0 +1,125 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `lang'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{lang}{2015/07/21 language settings for chemmacros}
+
+\RequirePackage{translations}
+
+\msg_new:nnn {chemmacros} {language-not-defined}
+  {
+    You~ chose~ the~ language~ `#1'~ which~ is~ not~ defined~ by~ chemmacros.~
+    `english'~ is~ used~ instead.~ If~ you~ just~ mistyped~ try~ again!~
+    Otherwise~ contact~ the~ author~ and~ he'll~ probably~ add~ your~ language.
+  }
+
+% --------------------------------------------------------------------------
+% language settings:
+\bool_new:N      \l__chemmacros_language_auto_bool
+\bool_set_true:N \l__chemmacros_language_auto_bool
+% this token list will hold the chosen language for chemmacros; since the
+% language is either chosen automatically or by option it is only available at
+% begin document
+\tl_new:N        \l_chemmacros_language_tl
+\tl_set:Nn       \l_chemmacros_language_tl { english }
+\tl_new:N        \l__chemmacros_current_language_tl
+
+% translate the key #1
+\cs_new:Npn \chemmacros_translate:n #1
+  {
+    \bool_if:NTF \l__chemmacros_language_auto_bool
+      { \GetTranslation{#1} }
+      { \GetTranslationFor{\l_chemmacros_language_tl}{#1} }
+  }
+
+\DeclareExpandableDocumentCommand \ChemTranslate {m}
+  { \chemmacros_translate:n {#1} }
+
+\AtBeginDocument{
+  \bool_if:NTF \l__chemmacros_language_auto_bool
+    {
+      \tl_set:Nx \l_chemmacros_language_tl
+        { \@trnslt@language{\@trnslt@current@language} }
+    }
+    {
+      \tl_set_eq:NN
+        \l_chemmacros_language_tl
+        \l__chemmacros_current_language_tl
+    }
+}
+
+\keys_define:nn {chemmacros}
+  {
+    language .value_required:n = true ,
+    language .code:n =
+      \tl_if_eq:nnTF { #1 } { auto }
+        { \bool_set_true:N \l__chemmacros_language_auto_bool }
+        {
+          \bool_set_false:N \l__chemmacros_language_auto_bool
+          \tl_set:Nn \l__chemmacros_current_language_tl { #1 }
+        } ,
+    % do we still need these?
+    german   .meta:n = { language = german } ,
+    german   .meta:n = { language = ngerman } ,
+    language .initial:n = auto
+  }
+
+% --------------------------------------------------------------------------
+\DeclareTranslationFallback  {scheme-name} {Scheme}
+\DeclareTranslation {German} {scheme-name} {Schema}
+
+\DeclareTranslationFallback  {scheme-list} {List~ of~ Schemes}
+\DeclareTranslation {German} {scheme-list} {Verzeichnis~ der~ Schemata}
+
+% --------------------------------------------------------------------------
+\DeclareTranslationFallback {K-acid}  {\mathrm{a}}
+\DeclareTranslation{German} {K-acid}  {\mathrm{s}}
+\DeclareTranslation{Dutch}  {K-acid}  {\mathrm{z}}
+
+\DeclareTranslationFallback {K-base}  {\mathrm{b}}
+
+\DeclareTranslationFallback {K-water} {\mathrm{w}}
+
+% --------------------------------------------------------------------------
+\DeclareTranslation{German}{phase-sld}{ f }
+\DeclareTranslation{German}{phase-lqd}{ f\/l }
+
+% --------------------------------------------------------------------------
+\DeclareTranslationFallback  {list-of-reactions} { List~ of~ Reactions }
+\DeclareTranslation{English} {list-of-reactions} { List~ of~ Reactions }
+\DeclareTranslation{German}  {list-of-reactions} { Reaktionsverzeichnis }
+\DeclareTranslation{Italian} {list-of-reactions} { Elenco~ delle~ reazioni }
+\DeclareTranslation{French}  {list-of-reactions} { Table~ des~ r\'eactions }
+\DeclareTranslation{Dutch}   {list-of-reactions} { Lijst~ van~ reacties }
+%
+\DeclareTranslationFallback  {reaction} { Reaction }
+\DeclareTranslation{English} {reaction} { Reaction }
+\DeclareTranslation{German}  {reaction} { Reaktion }
+\DeclareTranslation{Italian} {reaction} { Reazione }
+\DeclareTranslation{French}  {reaction} { R\'eaction }
+\DeclareTranslation{Dutch}   {reaction} { Reactie }
+% --------------------------------------------------------------------------
+
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.mechanisms.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.mechanisms.code.tex
new file mode 100644
index 00000000000..a2b3d205069
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.mechanisms.code.tex
@@ -0,0 +1,165 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `mechanisms'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{mechanisms}{2015/06/09 reaction mechanisms}
+
+\RequirePackage{amstext}
+
+% --------------------------------------------------------------------------
+% reaction mechanisms
+% \mech[<type>]
+% <type> - substitutions: {}, 1, 2, se, 1e, 2e, ar
+%        - eliminations:  e, e1, e2, cb
+\tl_new:N \l__chemmacros_mechanisms_type_tl
+\tl_new:N \l__chemmacros_mechanisms_mol_tl
+\tl_new:N \l__chemmacros_mechanisms_ar_tl
+
+\cs_new_protected:Npn \__chemmacros_set_mechanisms:nnn #1#2#3
+  {
+    \tl_set:Nn \l__chemmacros_mechanisms_type_tl { #1 }
+    \tl_set:Nn \l__chemmacros_mechanisms_mol_tl  { #2 }
+    \tl_set:Nn \l__chemmacros_mechanisms_ar_tl   { #3 }
+  }
+
+\keys_define:nn {chemmacros/mechanisms}
+  {
+    type      .choice: ,
+    type /    .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type / 1  .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+            1
+          }
+          { }
+      } ,
+    type / 2  .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+            2
+          }
+          { }
+      } ,
+    type / se .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type / 1e .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+            1
+          }
+          { }
+      } ,
+    type / 2e .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+            2
+          }
+          { }
+      } ,
+    type / ar .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+          }
+          { Ar - }
+      } ,
+    type / e  .code:n    =
+      { \__chemmacros_set_mechanisms:nnn { E } { } { } } ,
+    type / e1 .code:n    =
+      { \__chemmacros_set_mechanisms:nnn { E } { 1 } { } } ,
+    type / e2 .code:n    =
+      { \__chemmacros_set_mechanisms:nnn { E } { 2 } { } } ,
+    type / cb .code:n    =
+      {
+        \__chemmacros_set_mechanisms:nnn { E }
+          {
+            1
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {cb} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type      .default:n = 
+  }
+
+\cs_new_protected:Npn \chemmacros_mechanisms:n #1
+  {
+    \tl_if_blank:nTF {#1}
+      { \keys_set:nn {chemmacros/mechanisms} { type } }
+      { \keys_set:nn {chemmacros/mechanisms} { type = #1 } }
+    \mbox
+      {
+        \tl_use:N \l__chemmacros_mechanisms_ar_tl
+        \tl_use:N \l__chemmacros_mechanisms_type_tl
+        \tl_use:N \l__chemmacros_mechanisms_mol_tl
+      }
+  }
+
+\NewDocumentCommand \mech {o}
+  {
+    \IfNoValueTF {#1}
+      { \chemmacros_mechanisms:n { } }
+      { \chemmacros_mechanisms:n {#1} }
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.newman.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.newman.code.tex
new file mode 100644
index 00000000000..8d1df135388
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.newman.code.tex
@@ -0,0 +1,211 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `newman'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{newman}{2015/07/13 newman projections}
+
+\chemmacros_load_module:n {tikz}
+
+% Newman projections
+\fp_new:N  \l__chemmacros_newman_rel_angle_fp
+\fp_zero:N \l__chemmacros_newman_rel_angle_fp
+\fp_new:N  \l__chemmacros_newman_tmp_angle_fp
+\fp_new:N  \l__chemmacros_newman_abs_angle_fp
+\fp_zero:N \l__chemmacros_newman_abs_angle_fp
+\fp_new:N  \l__chemmacros_newman_scale_fp
+\fp_set:Nn \l__chemmacros_newman_scale_fp { 1 }
+\fp_new:N  \l__chemmacros_newman_x_fp
+\fp_new:N  \l__chemmacros_newman_y_fp
+
+\tl_new:N \l__chemmacros_newman_tikz_ring_tl
+\tl_new:N \l__chemmacros_newman_tikz_front_tl
+\tl_new:N \l__chemmacros_newman_tikz_back_tl
+
+\bool_new:N \l__chemmacros_newman_tikz_back_bool
+
+\keys_define:nn { chemmacros / newman }
+  {
+    ring       .tl_set:N  = \l__chemmacros_newman_tikz_ring_tl ,
+    atoms      .tl_set:N  = \l__chemmacros_newman_tikz_front_tl ,
+    back-atoms .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_newman_tikz_back_bool
+        \tl_set:Nn \l__chemmacros_newman_tikz_back_tl { #1 }
+      } ,
+    scale       .fp_set:N  = \l__chemmacros_newman_scale_fp ,
+    scale       .default:n = 1 ,
+    angle       .fp_set:N  = \l__chemmacros_newman_abs_angle_fp ,
+    angle       .default:n = 0
+  }
+
+% \newman[<keyval>](<angle>){<1>,<2>,<3>,<4>,<5>,<6>}
+\NewDocumentCommand \newman { o d() > { \SplitArgument { 5 } { , } } m }
+  {
+    \group_begin:
+      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / newman } { #1 } }
+      \IfNoValueTF { #2 }
+        { \chemmacros_newman_atoms:nnnnnnn {    } #3 }
+        { \chemmacros_newman_atoms:nnnnnnn { #2 } #3 }
+    \group_end:
+  }
+
+% place atoms:
+% #1: angle
+% #2 - #7: atoms
+\cs_new_protected:Npn \chemmacros_newman_atoms:nnnnnnn #1#2#3#4#5#6#7
+  {
+    \tl_if_blank:nTF { #1 }
+      {
+        \fp_set_eq:NN
+          \l__chemmacros_newman_rel_angle_fp
+          \l__chemmacros_newman_abs_angle_fp
+      }
+      { \fp_set:Nn \l__chemmacros_newman_rel_angle_fp { #1 } }
+    \chemmacros_tikz_picture:xn
+      {
+        scale = \fp_to_decimal:N \l__chemmacros_newman_scale_fp ,
+        chemmacros_newman_atom_front / .style =
+          {
+            inner~sep=0pt,
+            outer~sep=0pt,
+            \tl_use:N \l__chemmacros_newman_tikz_front_tl
+          },
+        chemmacros_newman_atom_back / .style =
+          {
+            inner~sep=0pt,
+            outer~sep=0pt,
+            \bool_if:NTF \l__chemmacros_newman_tikz_back_bool
+              { \tl_use:N \l__chemmacros_newman_tikz_back_tl }
+              { \tl_use:N \l__chemmacros_newman_tikz_front_tl }
+          }
+      }
+      {
+        \chemmacros_tikz_draw:x
+          { \exp_not:V \l__chemmacros_newman_tikz_ring_tl }
+          (0pt,0pt) circle (\fp_to_dim:N \l__chemmacros_newman_scale_fp * 15) ;
+        \chemmacros_newman_back_node:nn
+          { 30 }
+          { \IfNoValueF { #6 } { #6 } }
+        \chemmacros_newman_back_node:nf
+          { 150 }
+          { \IfNoValueF { #7 } { #7 } }
+        \chemmacros_newman_back_node:nf
+          { 270 }
+          { \IfNoValueF { #5 } { #5 } }
+        \chemmacros_newman_front_node:nf
+          { 90 }
+          { \IfNoValueF { #2 } { #2 } }
+        \chemmacros_newman_front_node:nf
+          { 210 }
+          { \IfNoValueF { #3 } { #3 } }
+        \chemmacros_newman_front_node:nf
+          { 330 }
+          { \IfNoValueF { #4 } { #4 } }
+    }
+  }
+
+% provide cartesian coordiantes from polar coordinates
+% #1: fp variable for x
+% #2: fp variable for y
+% #3: angle
+% #4: radius
+\cs_new_protected:Npn \chemmacros_polar_to_cartesian:NNnn #1#2#3#4
+  {
+    \fp_set:Nn #1 { #4 * cos( #3 / 180 * pi ) }% x
+    \fp_set:Nn #2 { #4 * sin( #3 / 180 * pi ) }% y
+  }
+
+% place back nodes
+\cs_new_protected:Npn \chemmacros_newman_back_node:nn #1#2
+  {
+    \group_begin:
+      \fp_add:Nn \l__chemmacros_newman_rel_angle_fp { #1 }
+      \chemmacros_polar_to_cartesian:NNnn
+        \l__chemmacros_newman_x_fp
+        \l__chemmacros_newman_y_fp
+        { \l__chemmacros_newman_rel_angle_fp }
+        { \l__chemmacros_newman_scale_fp }
+      \chemmacros_tikz_draw:x
+        { \exp_not:V \l__chemmacros_newman_tikz_ring_tl }
+        (
+          15 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          15 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        )
+        --
+        (
+          30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        ) ;
+      \chemmacros_polar_to_cartesian:NNnn
+        \l__chemmacros_newman_x_fp
+        \l__chemmacros_newman_y_fp
+        { \l__chemmacros_newman_rel_angle_fp }
+        { \l__chemmacros_newman_scale_fp }
+      \chemmacros_tikz_node:x
+        {
+          chemmacros_newman_atom_back,
+          anchor = -180 + \fp_to_int:N \l__chemmacros_newman_rel_angle_fp
+        }
+        at
+        (
+          31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        )
+        { #2 } ;
+    \group_end:
+  }
+\cs_generate_variant:Nn \chemmacros_newman_back_node:nn { nf }
+
+% place front nodes:
+\cs_new_protected:Npn \chemmacros_newman_front_node:nn #1#2
+  {
+    \chemmacros_polar_to_cartesian:NNnn
+      \l__chemmacros_newman_x_fp
+      \l__chemmacros_newman_y_fp
+      { #1 }
+      { \l__chemmacros_newman_scale_fp }
+    \chemmacros_tikz_draw:x
+      { \exp_not:V \l__chemmacros_newman_tikz_ring_tl }
+      (0pt,0pt) -- ++
+      (
+        30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+        30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+      ) ;
+    \chemmacros_polar_to_cartesian:NNnn
+      \l__chemmacros_newman_x_fp
+      \l__chemmacros_newman_y_fp
+      { #1 }
+      { \l__chemmacros_newman_scale_fp }
+    \chemmacros_tikz_node:x
+      { chemmacros_newman_atom_front, anchor = -180 + #1 }
+      at
+      (
+        31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+        31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+      )
+      { #2 } ;
+  }
+\cs_generate_variant:Nn \chemmacros_newman_front_node:nn { nf }
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.nomenclature.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.nomenclature.code.tex
new file mode 100644
index 00000000000..c13f3b10ded
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.nomenclature.code.tex
@@ -0,0 +1,622 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `nomenclature'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{nomenclature}{2015/09/09 chemical names}
+
+\RequirePackage{scrlfile}
+
+\chemmacros_load_module:n {tikz}
+
+\bool_new:N      \l__chemmacros_iupac_restricted_bool
+\bool_new:N      \l__chemmacros_iupac_strict_bool
+
+\msg_new:nnn {chemmacros} {new-iupac}
+  {
+    You've~ tried~ to~ define~ a~ iupac~ naming~ command~ with~
+    \token_to_str:N \NewChemIUPAC ,~ but~ the~ iupac~ command~
+    \token_to_str:N #1 \c_space_tl already~ exists.~ Choose~ another~ name~
+    or~ use~ \token_to_str:N \RenewChemIUPAC .
+  }
+
+\msg_new:nnn {chemmacros} {renew-iupac}
+  {
+    You've~ tried~ to~ renew~ the~ iupac~ command~ \token_to_str:N #1 ,~ but~
+    it~ doesn't~ exist.~ Use~ \token_to_str:N \NewChemIUPAC \c_space_tl
+    instead.
+  }
+
+\msg_new:nnn {chemmacros} {let-iupac}
+  {
+    You've~ tried~ to~ let~ the~ iupac~ command~ \token_to_str:N #1 ~ to~ the~
+    iupac~ command~ \token_to_str:N #2 ,~ but~ the~ latter~ doesn't~ exist.~
+    Use~ \token_to_str:N \NewChemIUPAC \c_space_tl instead~ or~declare~
+    \token_to_str:N #2 \c_space_tl first.
+  }
+
+\msg_new:nnn {chemmacros} {new-iupac-shorthand}
+  {
+    You've~ tried~ to~ define~ a~ iupac~ shorthand~ with~ \token_to_str:N
+    \NewChemIUPACShorthand ,~ but~ the~ shorthand~ \token_to_str:N #1
+    \c_space_tl already~ exists.~ Please~ choose~ another~ token.
+  }
+
+\msg_new:nnn {chemmacros} {renew-iupac-shorthand}
+  {
+    You've~ tried~ to~ renew~ the~ iupac~ shorthand~ \token_to_str:N #1 ,~
+    but~ this~ shorthand~ doesn't~ exist,~ yet.
+  }
+
+\prop_new:N \l__chemmacros_iupac_prop
+
+\cs_new_protected:Npn \chemmacros_new_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
+      { \msg_error:nnn {chemmacros} {new-iupac} {#1} }
+      {
+        \prop_put:NVn \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          {#2}
+      }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_provide_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_if_in:NVF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
+      {
+        \prop_put:NVn \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          {#2}
+      }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_define_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_put:NVn \l__chemmacros_iupac_prop
+      \l__chemmacros_tmpa_tl
+      {#2}
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
+      {
+        \prop_put:NVn \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          {#2}
+      }
+      { \msg_error:nnn {chemmacros} {renew-iupac} {#1} }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_let_iupac:NN #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \tl_set:Nx \l__chemmacros_tmpb_tl
+      { \chemmacros_remove_backslash:N #2 }
+    \prop_get:NVNTF \l__chemmacros_iupac_prop
+      \l__chemmacros_tmpb_tl
+      \l__chemmacros_tmpc_tl
+      {
+        \prop_put:NVV \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          \l__chemmacros_tmpc_tl
+      }
+      { \msg_error:nnnn {chemmacros} {let-iupac} {#1} {#2} }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_make_iupac:
+  {
+    \bool_if:NT \l__chemmacros_in_document_bool
+      {
+        \bool_if:NTF \l__chemmacros_inside_iupac_bool
+          {
+            \prop_map_inline:Nn \l__chemmacros_iupac_prop
+              { \cs_set_protected:cpn {##1} {##2} }
+          }
+          {
+            \bool_if:NF \l__chemmacros_iupac_restricted_bool
+              {
+                \bool_if:NTF \l__chemmacros_iupac_strict_bool
+                  {
+                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
+                      { \cs_set_protected:cpn {##1} {##2} }
+                  }
+                  {
+                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
+                      {
+                        \cs_if_exist:cF {##1}
+                          { \cs_set_protected:cpn {##1} {##2} }
+                      }
+                  }
+              }
+          }
+      }    
+  }
+
+\AtBeginDocument { \chemmacros_make_iupac: }
+
+\NewDocumentCommand \DeclareChemIUPAC { mm }
+  { \chemmacros_define_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \NewChemIUPAC { mm }
+  { \chemmacros_new_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \RenewChemIUPAC { mm }
+  { \chemmacros_renew_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \ProvideChemIUPAC { mm }
+  { \chemmacros_provide_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \LetChemIUPAC { mm }
+  { \chemmacros_let_iupac:NN #1 #2 }
+
+\keys_define:nn {chemmacros/nomenclature}
+  {
+    iupac              .choice: ,
+    iupac / restricted .code:n     =
+      \bool_set_true:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
+    iupac / auto       .code:n     =
+      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
+    iupac / strict     .code:n     =
+      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_true:N \l__chemmacros_iupac_strict_bool ,
+  }
+
+% stereo descriptors and other nomenclature commands
+% Cahn-Ingold-Prelog
+\dim_new:N  \l__chemmacros_cip_kern_dim
+\dim_set:Nn \l__chemmacros_cip_kern_dim { .075em }
+
+\keys_define:nn {chemmacros/nomenclature}
+  { cip-kern .dim_set:N = \l__chemmacros_cip_kern_dim }
+
+\NewDocumentCommand \cip { m }
+  { \chemmacros_cip:n { #1 } }
+
+\cs_new_protected:Npn \chemmacros_cip:n #1
+  { ( \textit{#1} \tex_kern:D \l__chemmacros_cip_kern_dim ) }
+
+% remember: TikZ needs : to be other
+\cs_new_protected:Npn \chemmacros_sconf:n #1
+  {
+    \group_begin:
+      \chemmacros_tikz:nn
+        { baseline,text~ height=1.5ex,text~ depth=.25ex }
+        {
+          \chemmacros_tikz_node:n {anchor=base} (chemmacros@@Sconf) {#1} ;
+          \chemmacros_tikz_draw:n {->,thick,rotate=90}
+            ($(chemmacros@@Sconf.center)+(20\c_chemmacros_other_colon_tl.8em)$)
+            arc (20\c_chemmacros_other_colon_tl340\c_chemmacros_other_colon_tl.8em);
+        }
+    \group_end:
+  }
+
+\cs_new_protected:Npn \chemmacros_rconf:n #1
+  {
+    \group_begin:
+      \tikz[baseline,text~ height=1.5ex,text~ depth=.25ex]
+        {
+          \chemmacros_tikz_node:n {anchor=base} (chemmacros@@Rconf) {#1} ;
+          \chemmacros_tikz_draw:n {<-,thick,rotate=90}
+            ($(chemmacros@@Rconf.center)+(20\c_chemmacros_other_colon_tl.8em)$)
+            arc (20\c_chemmacros_other_colon_tl340\c_chemmacros_other_colon_tl.8em) ;
+        }
+    \group_end:
+  }
+
+\NewDocumentCommand \Sconf { O{S} } { \chemmacros_sconf:n {#1} }
+\NewDocumentCommand \Rconf { O{R} } { \chemmacros_rconf:n {#1} }
+
+% coordination chemistry
+\bool_new:N \l__chemmacros_bridge_super_bool
+
+\keys_define:nn { chemmacros / nomenclature }
+  {
+    bridge-number         .choice: ,
+    bridge-number / sub   .code:n     =
+      \bool_set_false:N \l__chemmacros_bridge_super_bool ,
+    bridge-number / super .code:n     =
+      \bool_set_true:N \l__chemmacros_bridge_super_bool ,
+    coord-use-hyphen      .bool_set:N = \l__chemmacros_coord_use_hyphen_bool ,
+    coord-use-hyphen      .initial:n  = true
+  }
+
+\cs_new_protected:Npn \chemformula_hapto:n #1
+  {
+    \chemmacros_chemformula:n { \chemeta ^{#1} }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+\cs_new_protected:Npn \chemformula_dento:n #1
+  {
+    \chemmacros_chemformula:n { \chemkappa ^{#1} }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+\cs_new_protected:Npn \chemformula_bridge:n #1
+  {
+    \chemmacros_chemformula:n {\chemmu}
+    \tl_if_blank:nF { #1 }
+      {
+        \bool_if:NTF \l__chemmacros_bridge_super_bool
+          { \chemmacros_chemformula:n { {}^{#1} } }
+          { \chemmacros_chemformula:n { {}_{#1} } }
+      }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+% \iupac (basically the same as bpchem's \IUPAC)
+% - allows multiple breaking points as compound names can get really long and
+%   especially in multicolumn documents can span more than two lines
+% - add a (very) little space before the hyphen and a little negative space
+%   after it
+% - add a little space at breaking points if not broken
+% - enables all naming commands regardless if they're definied otherwise or not
+\cs_new_protected:Npn \chemmacros_allow_hyphens:
+  {
+    \chemmacros_nobreak:
+    \skip_horizontal:N \c_zero_dim
+  }
+
+\dim_new:N  \l__chemmacros_iupac_hyphen_pre_dim
+\dim_set:Nn \l__chemmacros_iupac_hyphen_pre_dim { .01em }
+\dim_new:N  \l__chemmacros_iupac_hyphen_post_dim
+\dim_set:Nn \l__chemmacros_iupac_hyphen_post_dim { -.03em }
+\dim_new:N  \l__chemmacros_iupac_break_dim
+\dim_set:Nn \l__chemmacros_iupac_break_dim { .03em }
+
+\keys_define:nn { chemmacros / nomenclature }
+  {
+    hyphen-pre-space  .dim_set:N = \l__chemmacros_iupac_hyphen_pre_dim ,
+    hyphen-post-space .dim_set:N = \l__chemmacros_iupac_hyphen_post_dim ,
+    break-space       .dim_set:N = \l__chemmacros_iupac_break_dim
+  }
+
+% #1: pre break
+% #2: post break
+% #3: no break
+\cs_new_protected:Npn \__chemmacros_break_point_insert:nnn #1#2#3
+  {
+    \mode_if_math:TF
+      {#3}
+      {
+        \chemmacros_nobreak:
+        \tex_discretionary:D {#1} {#2} {#3}
+        \chemmacros_allow_hyphens:
+      }
+  }
+\cs_new_protected:Npn \chemmacros_break_point_hyphen:
+  {
+    \__chemmacros_break_point_insert:nnn
+      {-}
+      { }
+      {
+        \tex_kern:D \l__chemmacros_iupac_hyphen_pre_dim
+        -
+        \tex_kern:D \l__chemmacros_iupac_hyphen_post_dim
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_break_point:
+  {
+    \__chemmacros_break_point_insert:nnn
+      {-}
+      { }
+      {
+        \mode_if_math:TF
+          { | }
+          { \tex_kern:D \l__chemmacros_iupac_break_dim }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_break_point_opening_paren:
+  { \__chemmacros_break_point_insert:nnn { - } { ( } { ( } }
+
+\cs_new_protected:Npn \chemmacros_break_point_closing_paren:
+  { \__chemmacros_break_point_insert:nnn { )- } { } { ) } }
+
+\cs_new_protected:Npn \chemmacros_break_point_opening_bracket:
+  { \__chemmacros_break_point_insert:nnn { - } { [ } { [ } }
+
+\cs_new_protected:Npn \chemmacros_break_point_closing_bracket:
+  { \__chemmacros_break_point_insert:nnn { ]- } { } { ] } }
+  
+\cs_new_protected:Npn \chemmacros_superscript:n #1
+  { \mode_if_math:TF { \sp {#1} } { \textsuperscript {#1} } }
+  
+\bool_new:N \l__chemmacros_inside_iupac_bool
+
+\seq_new:N   \l__chemmacros_iupac_shorthands_seq
+
+% #1: token
+% #2: arg spec
+\cs_new_protected:Npn \chemmacros_define_iupac_shorthand:NN #1#2
+  {
+    \seq_if_in:NnF \l__chemmacros_iupac_shorthands_seq {#1}
+      { \seq_put_right:Nn \l__chemmacros_iupac_shorthands_seq {#1} }
+    \char_set_active_eq:NN #1#2
+  }
+
+\cs_new_protected:Npn \chemmacros_remove_shorthand:N #1
+  {
+    \chemmacros_define_iupac_shorthand:Npn #1 {}
+    \seq_remove_all:Nn \l__chemmacros_iupac_shorthands_seq {#1}
+  }
+
+\cs_new_protected:Npn \chemmacros_activate_iupac_shorthands:n #1
+  {
+    \tl_map_inline:nn {#1}
+      {
+        \seq_if_in:NnT \l__chemmacros_iupac_shorthands_seq {##1}
+          { \char_set_catcode_active:N ##1 }
+      }
+  }
+\cs_new_protected:Npn \chemmacros_activate_all_iupac_shorthands:
+  {
+    \seq_map_inline:Nn \l__chemmacros_iupac_shorthands_seq
+     { \char_set_catcode_active:N ##1 }
+  }
+      
+\NewDocumentCommand \DeclareChemIUPACShorthand {mm} 
+  { \chemmacros_define_iupac_shorthand:NN #1#2 }
+
+\NewDocumentCommand \NewChemIUPACShorthand {mm} 
+  {
+    \seq_if_in:NnTF \l__chemmacros_iupac_shorthands_seq {#1}
+      { \msg_error:nnn {chemmacros} {new-iupac-shorthand} {#1} }
+      { \chemmacros_define_iupac_shorthand:NN #1#2 }
+  }
+
+\NewDocumentCommand \ProvideChemIUPACShorthand {mm} 
+  {
+    \seq_if_in:NnF \l__chemmacros_iupac_shorthands_seq {#1}
+      { \chemmacros_define_iupac_shorthand:NN #1#2 }
+  }
+
+\NewDocumentCommand \RenewChemIUPACShorthand {mm} 
+  {
+    \seq_if_in:NnTF \l__chemmacros_iupac_shorthands_seq {#1}
+      { \chemmacros_define_iupac_shorthand:NN #1#2 }
+      { \msg_error:nnn {chemmacros} {renew-iupac-shorthand} {#1} }
+  }
+
+\NewDocumentCommand \RemoveChemIUPACShorthand {m} 
+  { \chemmacros_remove_shorthand:N #1 }
+
+\group_begin:
+\chemmacros_activate_all_iupac_shorthands:
+
+\cs_new_protected:Npn \chemmacros_iupac:n #1
+  {
+    \group_begin:
+      \bool_set_true:N \l__chemmacros_inside_iupac_bool
+      \chemmacros_make_iupac:
+      \chemmacros_ignore_spaces:
+      \chemmacros_if_compatiblity:nnT {<=} {5.2}
+        { \chemmacros_define_deprecated:NN \- - }
+      \tl_set_rescan:Nnn \l__chemmacros_tmpa_tl
+        { \chemmacros_activate_all_iupac_shorthands: }
+        {#1}
+      \l__chemmacros_tmpa_tl
+    \group_end:
+  }
+\group_end:
+
+\NewChemIUPACShorthand | \chemmacros_break_point:
+\NewChemIUPACShorthand - \chemmacros_break_point_hyphen:
+\NewChemIUPACShorthand ( \chemmacros_break_point_opening_paren:
+\NewChemIUPACShorthand ) \chemmacros_break_point_closing_paren:
+\NewChemIUPACShorthand [ \chemmacros_break_point_opening_bracket:
+\NewChemIUPACShorthand ] \chemmacros_break_point_closing_bracket:
+\NewChemIUPACShorthand ^ \chemmacros_superscript:n
+
+% Thanks to Joseph Wright and Enrico Gregorio for the help on the curious
+% redefinition of \- and the end of the compilation
+% see http://tex.stackexchange.com/q/42405/5049 for reference
+\cs_set_protected:Npx \- { \exp_not:o { \- } }
+\cs_set_eq:NN \@dischyph \-
+
+\NewDocumentCommand \iupac {m} { \chemmacros_iupac:n {#1} }
+
+% --------------------------------------------------------------------------
+% R(ectus)/S(inister):
+\NewChemIUPAC \rectus   { \cip {R} }
+\NewChemIUPAC \sinister { \cip {S} }
+
+\LetChemIUPAC \R \rectus
+\LetChemIUPAC \S \sinister
+
+% E(ntgegen)/Z(usammen)
+\NewChemIUPAC \entgegen { \cip {E} }
+\NewChemIUPAC \zusammen { \cip {Z} }
+
+\LetChemIUPAC \E \entgegen
+\LetChemIUPAC \Z \zusammen
+
+% cis/trans
+\NewChemIUPAC \cis   { \textit {cis} }
+\NewChemIUPAC \trans { \textit {trans} }
+
+% fac/mer
+\NewChemIUPAC \fac { \textit {fac} }
+\NewChemIUPAC \mer { \textit {mer} }
+
+% tert
+\NewChemIUPAC \tert  { \textit {tert} }
+
+% Italian descriptors - I forgot what they mean
+\NewChemIUPAC \sin { \textit {sin} }
+\NewChemIUPAC \ter { \textit {ter} }
+
+% Fischer
+\NewChemIUPAC \dexter { \textsc {d} }
+\NewChemIUPAC \laevus { \textsc {l} }
+
+\LetChemIUPAC \D \dexter
+\LetChemIUPAC \L \laevus
+
+% ortho/meta/para
+\NewChemIUPAC \ortho { \textit {o} }
+\NewChemIUPAC \meta  { \textit {m} }
+\NewChemIUPAC \para  { \textit {p} }
+
+% syn/anti
+\NewChemIUPAC \syn  { \textit {syn} }
+\NewChemIUPAC \anti { \textit {anti} }
+
+% coordination chemistry:
+\NewChemIUPAC \hapto  { \chemformula_hapto:n }
+\NewChemIUPAC \dento  { \chemformula_dento:n }
+\NewChemIUPAC \bridge { \chemformula_bridge:n }
+
+% attachments to heteroatoms / added hydrogen
+\NewChemIUPAC \hydrogen   { \textit {H} }
+\NewChemIUPAC \oxygen     { \textit {O} }
+\NewChemIUPAC \nitrogen   { \textit {N} }
+\NewChemIUPAC \sulfur     { \textit {S} }
+\NewChemIUPAC \phosphorus { \textit {P} }
+
+% atoms:
+\LetChemIUPAC \H  \hydrogen
+\LetChemIUPAC \O  \oxygen
+\LetChemIUPAC \N  \nitrogen
+\LetChemIUPAC \Sf \sulfur
+\LetChemIUPAC \P  \phosphorus
+
+% greek letters
+\NewChemIUPAC \a { \chemalpha }
+\NewChemIUPAC \b { \chembeta }
+\NewChemIUPAC \g { \chemgamma }
+\NewChemIUPAC \d { \chemdelta }
+\NewChemIUPAC \k { \chemkappa }
+\NewChemIUPAC \m { \chemmu }
+\NewChemIUPAC \n { \chemeta }
+\NewChemIUPAC \w { \chemomega }
+
+% --------------------------------------------------------------------------
+% latin phrases
+\tl_new:N  \l__chemmacros_latin_format_tl
+\tl_set:Nn \l__chemmacros_latin_format_tl { \itshape }
+
+\keys_define:nn { chemmacros / nomenclature }
+  {
+    latin-format .tl_set:N  = \l__chemmacros_latin_format_tl ,
+    latin-format .initial:n = \textit
+  }
+
+\cs_new_protected:Npn \chemmacros_latin:n #1
+  { { \l__chemmacros_latin_format_tl {#1} } }
+
+\cs_new_protected:Npn \chemmacros_define_latin:Nn #1#2
+  { \cs_set_protected:Npn #1 { \chemmacros_latin:n {#2} } }
+
+\chemmacros_new_macroset:nnn {Latin} {mm}
+  { \chemmacros_define_latin:Nn #1 {#2} }
+
+\AtBeginDocument
+  {
+    % if chemstyle is loaded use chemstyle's definition:
+    \chemmacros_if_package_loaded:nTF {chemstyle}
+      {
+        \AfterPackage* {chemstyle}
+          {
+            \cs_undefine:N \invacuo
+            \cs_set_eq:NN \chemmacros_latin:n \cst@latin
+          }
+      }
+      { \cs_new_eq:NN  \latin \chemmacros_latin:n }
+    \NewChemLatin \insitu   {in~situ}
+    \NewChemLatin \abinitio {ab~initio}
+    \NewChemLatin \invacuo  {in~vacuo}
+  }
+
+% --------------------------------------------------------------------------
+% hyperref support
+% ?? unsure about adding IUPAC commands
+\AfterPackage* { hyperref }
+  {
+    \pdfstringdefDisableCommands
+      {
+        % \cs_set:Npn \- { - } % maybe not a good idea...
+        \cs_set:Npn \| { }
+        % \cs_set:Npn \pH { pH }
+        % \cs_set:Npn \pOH { pOH }
+        \cs_set:Npn \iupac #1 {#1}
+        \cs_set:Npn \cip   #1 {(#1)}
+        \cs_set:Npn \cis   {cis}
+        \cs_set:Npn \trans {trans}
+        \cs_set:Npn \tert  {tert}
+        \cs_set:Npn \ortho {o}
+        \cs_set:Npn \meta  {m}
+        \cs_set:Npn \para  {p}
+        \cs_set:Npn \syn   {syn}
+        \cs_set:Npn \anti  {anti}
+        \cs_set:Npn \R     {(R)}
+        \cs_set:Npn \S     {(S)}
+        \cs_set:Npn \E     {(E)}
+        \cs_set:Npn \Z     {(Z)}
+        \cs_set:Npn \D     {D}
+        \cs_set:Npn \L     {L}
+        \cs_set:Npn \H     {H}
+        \cs_set:Npn \O     {O}
+        \cs_set:Npn \N     {N}
+        \cs_set:Npn \Sf    {S}
+        \cs_set:Npn \P     {P}
+        \cs_set:Npn \dexter     {D}
+        \cs_set:Npn \laevus     {L}
+        \cs_set:Npn \rectus     {(R)}
+        \cs_set:Npn \sinister   {(S)}
+        \cs_set:Npn \entgegen   {(E)}
+        \cs_set:Npn \zusammen   {(Z)}
+        \cs_set:Npn \hydrogen   {H}
+        \cs_set:Npn \oxygen     {O}
+        \cs_set:Npn \nitrogen   {N}
+        \cs_set:Npn \sulfur     {S}
+        \cs_set:Npn \phosphorus {P}
+      }
+  }
+  
+% --------------------------------------------------------------------------
+\tex_endinput:D
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.orbital.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.orbital.code.tex
new file mode 100644
index 00000000000..e7f0eac2f56
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.orbital.code.tex
@@ -0,0 +1,570 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `orbital'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{orbital}{2015/07/14 drawing orbital shapes}
+
+\chemmacros_load_module:n {tikz}
+
+% \orbital[<keyval>]{<type>}
+% variables:
+\bool_new:N      \l__chemmacros_orbital_type_s_bool
+\bool_new:N      \l__chemmacros_orbital_type_p_bool
+\bool_new:N      \l__chemmacros_orbital_type_sp_bool
+\bool_new:N      \l__chemmacros_orbital_type_sptwo_bool
+\bool_new:N      \l__chemmacros_orbital_type_spthree_bool
+\bool_new:N      \l__chemmacros_orbital_s_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_s_phase_bool
+\bool_new:N      \l__chemmacros_orbital_p_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_p_phase_bool
+\bool_new:N      \l__chemmacros_orbital_sp_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_sp_phase_bool
+\bool_new:N      \l__chemmacros_orbital_sptwo_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool
+\bool_new:N      \l__chemmacros_orbital_spthree_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool
+\bool_new:N      \l__chemmacros_orbital_p_half_bool
+\bool_new:N      \l__chemmacros_orbital_overlay_bool
+\bool_new:N      \l__chemmacros_orbital_opacity_bool
+
+\tl_new:N  \l__chemmacros_orbital_s_color_tl
+\tl_set:Nn \l__chemmacros_orbital_s_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_s_phase_color_tl
+\tl_new:N  \l__chemmacros_orbital_p_color_tl
+\tl_set:Nn \l__chemmacros_orbital_p_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_p_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_p_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sp_color_tl
+\tl_set:Nn \l__chemmacros_orbital_sp_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_sp_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sp_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sptwo_color_tl
+\tl_set:Nn \l__chemmacros_orbital_sptwo_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_sptwo_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sptwo_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_spthree_color_tl
+\tl_set:Nn \l__chemmacros_orbital_spthree_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_spthree_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_spthree_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_s_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_s_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_p_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_p_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_sp_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_sp_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_sptwo_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_sptwo_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_spthree_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_spthree_scale_tl { 1 }
+
+\fp_new:N  \l__chemmacros_orbital_angle_fp
+\fp_set:Nn \l__chemmacros_orbital_angle_fp { 90 }
+\fp_new:N  \l__chemmacros_orbital_opacity_fp
+\fp_set:Nn \l__chemmacros_orbital_opacity_fp { 0.5 }
+
+\cs_new:Npn \__chemmacros_orbital_options:
+  {
+    \__chemmacros_orbital_overlay: , \__chemmacros_orbital_opacity: ,
+    inner~sep=0 , outer~sep=0 , line~width=.2pt ,
+    rotate = { \fp_use:N \l__chemmacros_orbital_angle_fp - 90 } ,
+    baseline ,
+    minimum~size = 0
+  }
+
+\cs_new:Npn \__chemmacros_orbital_overlay:
+  { \bool_if:NT \l__chemmacros_orbital_overlay_bool { overlay } }
+
+\cs_new:Npn \__chemmacros_orbital_opacity:
+  {
+    \bool_if:NT \l__chemmacros_orbital_opacity_bool
+      { opacity = { \fp_use:N \l__chemmacros_orbital_opacity_fp } }
+  }
+
+% --------------------------------------------------------------------------
+% s-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_s:
+  {
+    \bool_set_true:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / s }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_s_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_s_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_s_scale_tl ,
+    color .tl_set:N   = \l__chemmacros_orbital_s_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_s_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / s } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_s_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_s_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_s_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_s_color_tl ! 90 }
+          }
+      }
+      {
+        \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn{ \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shade:x
+          { ball~color = \exp_not:V \l__chemmacros_orbital_s_phase_color_tl }
+          (0pt,0pt) circle (\exp_not:V \l__chemmacros_orbital_s_scale_tl * .6em) ;
+      }
+  }
+
+% --------------------------------------------------------------------------
+% p-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_p:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / p }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_p_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_p_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_p_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_p_color_tl ,
+    half  .bool_set:N = \l__chemmacros_orbital_p_half_bool ,
+    half  .default:n  = true
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_p_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / p } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_p_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_p_pphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_p_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_p_scale_tl * 2em ,
+            \l__chemmacros_orbital_p_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_p_scale_tl * 2em ,
+            \l__chemmacros_orbital_p_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \bool_if:NF \l__chemmacros_orbital_p_half_bool
+          {
+            \chemmacros_tikz_shadedraw:x
+              {
+                draw = \exp_not:V \l__chemmacros_orbital_p_mphase_color_tl ,
+                ball~color = \exp_not:V \l__chemmacros_orbital_p_mphase_color_tl
+              }
+              (0pt,0pt) .. controls ++
+              (
+                - \l__chemmacros_orbital_p_scale_tl * 2em ,
+                - \l__chemmacros_orbital_p_scale_tl * 2em
+              )
+              and ++
+              (
+                \l__chemmacros_orbital_p_scale_tl * 2em ,
+                - \l__chemmacros_orbital_p_scale_tl * 2em
+              )
+              .. (0pt,0pt);
+          }
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_sp:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_sp_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_sp_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_sp_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_sp_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_sp_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_sp_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_sp_pphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_sp_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sp_scale_tl * 2em ,
+            \l__chemmacros_orbital_sp_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sp_scale_tl * 2em ,
+            \l__chemmacros_orbital_sp_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_sp_mphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_sp_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sp_scale_tl * .6em ,
+            - \l__chemmacros_orbital_sp_scale_tl * .6em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sp_scale_tl * .6em ,
+            - \l__chemmacros_orbital_sp_scale_tl * .6em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp2-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_sptwo:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp2 }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_sptwo_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_sptwo_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_sptwo_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_sptwo_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp2 } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_sptwo_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_sptwo_pphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_sptwo_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_sptwo_mphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_sptwo_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp3-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_spthree:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp3 }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool } ,
+    phase / - .code:n =
+     { \bool_set_false:N \l__chemmacros_orbital_spthree_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_spthree_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_spthree_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_spthree_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp3 } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_spthree_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_spthree_pphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_spthree_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_spthree_scale_tl * 2em ,
+            \l__chemmacros_orbital_spthree_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_spthree_scale_tl * 2em ,
+            \l__chemmacros_orbital_spthree_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:x
+          {
+            draw = \exp_not:V \l__chemmacros_orbital_spthree_mphase_color_tl ,
+            ball~color = \exp_not:V \l__chemmacros_orbital_spthree_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em ,
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_spthree_scale_tl * 1em ,
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% main command
+\keys_define:nn { chemmacros / orbital }
+  {
+    overlay .bool_set:N = \l__chemmacros_orbital_overlay_bool ,
+    overlay .default:n  = true ,
+    opacity .code:n     =
+      {
+        \fp_compare:nTF { #1 = 1 }
+          { \bool_set_false:N \l__chemmacros_orbital_opacity_bool }
+          { \bool_set_true:N \l__chemmacros_orbital_opacity_bool }
+        \fp_set:Nn \l__chemmacros_orbital_opacity_fp { #1 }
+      }
+  }
+
+\keys_define:nn { chemmacros / orbital / type }
+  {
+    s   .code:n = { \__chemmacros_orbital_type_s: } ,
+    p   .code:n = { \__chemmacros_orbital_type_p: } ,
+    sp  .code:n = { \__chemmacros_orbital_type_sp: } ,
+    sp2 .code:n = { \__chemmacros_orbital_type_sptwo: } ,
+    sp3 .code:n = { \__chemmacros_orbital_type_spthree: }
+  }
+
+\cs_new_protected:Npn \chemmacros_orbital:n #1
+  {
+    \bool_if:NT \l__chemmacros_orbital_type_s_bool
+      { \__chemmacros_orbital_s_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_p_bool
+      { \__chemmacros_orbital_p_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_sp_bool
+      { \__chemmacros_orbital_sp_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_sptwo_bool
+      { \__chemmacros_orbital_sptwo_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_spthree_bool
+      { \__chemmacros_orbital_spthree_draw:n { #1 } }
+  }
+
+\NewDocumentCommand \orbital { o m }
+  {
+    \group_begin:
+      \keys_set:nn { chemmacros / orbital / type } { #2 }
+      \IfNoValueTF { #1 }
+        { \chemmacros_orbital:n {    } }
+        { \chemmacros_orbital:n { #1 } }
+    \group_end:
+  }
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.particles.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.particles.code.tex
new file mode 100644
index 00000000000..110dd05c8ea
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.particles.code.tex
@@ -0,0 +1,118 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `particles'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{particles}{2015/07/15 particles}
+  
+\chemmacros_load_modules:n {charges,chemformula}
+
+% --------------------------------------------------------------------------
+% particles
+\cs_new_protected:Nn \chemmacros_define_particle:Nn
+  { \cs_set_protected:Npn #1 { \chemformula_chcpd:nn {} {#2} } }
+
+\chemmacros_new_macroset:nnn {Particle} {mm}
+  { \chemmacros_define_particle:Nn #1 {#2} }
+
+% --------------------------------------------------------------------------
+% nucleophiles
+\cs_new_protected:Npn \chemmacros_elpair:n #1
+  {
+    \bool_if:NTF \l__chemmacros_elpair_dots_bool
+      { \chlewis { 0: } {#1} }
+      { \chlewis { 0| } {#1} }
+  }
+
+\bool_new:N \l__chemmacros_nucleophile_elpair_bool
+\bool_new:N \l__chemmacros_elpair_dots_bool
+
+\keys_define:nn {chemmacros/particles}
+  {
+    elpair         .choice: ,
+    elpair / false .code:n    =
+      { \bool_set_false:N \l__chemmacros_nucleophile_elpair_bool } ,
+    elpair / dots  .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_nucleophile_elpair_bool
+        \bool_set_true:N \l__chemmacros_elpair_dots_bool
+      } ,
+    elpair / dash  .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_nucleophile_elpair_bool
+        \bool_set_false:N \l__chemmacros_elpair_dots_bool
+      } ,
+    elpair         .default:n = dots
+  }
+
+\cs_new_protected:Npn \chemmacros_declare_nucleophile:Nn #1#2
+  {
+    \cs_set_protected:cpn {__chemmacros_ \chemmacros_remove_backslash:N #1:}
+      {
+        \bool_if:NTF \l__chemmacros_nucleophile_elpair_bool
+          { \chemmacros_elpair:n { #2 } \chemmacros_chemformula:n { {}- } }
+          { \chemmacros_chemformula:n { #2- } }
+      }
+    \DeclareDocumentCommand #1 {o}
+      {
+        \group_begin:
+          \IfNoValueF {##1}
+            { \keys_set:nn {chemmacros/particles} {##1} }
+          \use:c {__chemmacros_ \chemmacros_remove_backslash:N #1:}
+        \group_end:
+      }
+  }
+
+\chemmacros_new_macroset:nnn {Nucleophile} {mm}
+  { \chemmacros_declare_nucleophile:Nn #1 {#2} }
+
+
+
+% --------------------------------------------------------------------------
+% particles:
+\NewChemParticle \el  { e- }
+\NewChemParticle \prt { p+ }
+\NewChemParticle \ntr { n^0 }
+
+% ions, molecules
+% proton, hydroxide, hydronium/oxonium, water:
+\NewChemParticle \Hpl { H+ }
+\NewChemParticle \Hyd { OH- }
+\NewChemParticle \Oxo { H3O+ }
+\NewChemParticle \water { H2O }
+
+% electrophile:
+\NewChemParticle \El  { E+ }
+
+% nucleophiles:
+\NewChemNucleophile \Nuc {Nu}
+\NewChemNucleophile \ba  {ba}
+
+\ChemCompatibilityTo{5.2}
+  \DeclareChemDeprecated \Hto \Oxo
+  \DeclareChemDeprecated \Nu \Nuc
+\EndChemCompatibility
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.phases.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.phases.code.tex
new file mode 100644
index 00000000000..cbc6fe23039
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.phases.code.tex
@@ -0,0 +1,84 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `phases'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{phases}{2015/06/09 phase descriptors}
+
+\chemmacros_load_module:n {chemformula}
+
+\bool_new:N \l__chemmacros_phases_sub_bool
+\dim_new:N  \l__chemmacros_phases_space_dim
+\dim_set:Nn \l__chemmacros_phases_space_dim { .1333 em }
+
+\keys_define:nn {chemmacros/phases}
+  {
+    pos        .choice: ,
+    pos / sub  .code:n    = \bool_set_true:N \l__chemmacros_phases_sub_bool ,
+    pos / side .code:n    = \bool_set_false:N \l__chemmacros_phases_sub_bool ,
+    space      .dim_set:N = \l__chemmacros_phases_space_dim
+  }
+
+\chemmacros_new_macroset:nnn {Phase} {mm} { \chemmacros_define_phase:Nn #1 {#2} }
+
+\cs_new_protected:Npn \chemmacros_define_phase:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl { phase-\chemmacros_remove_backslash:N #1 }
+    \exp_args:NV \@trnslt@declare@translation
+      \l__chemmacros_tmpa_tl
+      {fallback}
+      {#2}
+    \__chemmacros_define_phase:Nx #1
+      { \exp_not:N \chemmacros_translate:n { \exp_not:V \l__chemmacros_tmpa_tl } }
+  }
+
+\cs_new_protected:Npn \__chemmacros_define_phase:Nn #1#2
+  {
+    \cs_if_exist:NF #1 { \cs_new:Npn #1 {} }
+    \DeclareDocumentCommand #1 {o}
+      { \chemmacros_phase:n { #2 \IfNoValueF {##1} {,~##1} } }
+  }
+\cs_generate_variant:Nn \__chemmacros_define_phase:Nn { Nx }
+
+\cs_new_protected:Npn \chemmacros_phase:n #1
+  {
+    \chemmacros_leave_vmode:
+    \bool_if:NTF \l__chemmacros_phases_sub_bool
+      { \chemformula_subscript:n { (#1) } }
+      {
+        \skip_horizontal:N \l__chemmacros_phases_space_dim
+        \chemmacros_text:n { (#1) }
+      }
+  }
+
+% --------------------------------------------------------------------------
+\NewDocumentCommand \phase {m} { \chemmacros_phase:n {#1} }
+
+\NewChemPhase \sld {s}
+\NewChemPhase \lqd {l}
+\NewChemPhase \gas {g}
+\NewChemPhase \aq  {aq}
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.reactions.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.reactions.code.tex
new file mode 100644
index 00000000000..087cd521e69
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.reactions.code.tex
@@ -0,0 +1,185 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `reactions'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{reactions}{2015/07/14 reaction environments}
+
+\chemmacros_load_module:n {chemformula}
+
+\RequirePackage{mathtools}
+
+% --------------------------------------------------------------------------
+\cs_new_protected:Npn \__chemmacros_record_for_lor:nnnnn #1#2#3#4#5
+  {
+    \tl_if_eq:nnT { #1 } { reaction }
+      {
+        \group_begin:
+          % we need to prevent \Hy@make@anchor from being written to the lor
+          % file:
+          \bool_if:NT \l__chemmacros_hyperref_bool
+            { \cs_set:Npn \Hy@make@anchor {} }
+          \addcontentsline { lor } { reaction }
+            {
+              \tl_use:N \l__chemmacros_reaction_lorname_tl
+              \tl_use:N \c_space_tl
+              #2 #3 #4 #5
+              \tl_use:N \g__chemmacros_reaction_description_tl
+            }
+          \tl_gclear:N \g__chemmacros_reaction_description_tl
+        \group_end:
+      }
+  }
+
+% redefine mathtools' command \MT_define_tagform:nwnn to ensure we add an
+% entry to the list of reactions even if the user redefines the reaction tag
+% this should probably be done via patching...
+\AfterPackage* { mathtools }
+  {
+    \cs_set_protected:Npn \MT_define_tagform:nwnn #1[#2]#3#4
+      {
+        \@namedef{MT_tagform_#1:n}##1
+          {
+            % this is the original part:
+            \maketag@@@{#3\ignorespaces#2{##1}\unskip\@@italiccorr#4}
+            % this is added => this disturbs hyperref:
+            \__chemmacros_record_for_lor:nnnnn
+              { #1 } { #3 } { #2 } { ##1 } { #4 }
+          }
+      }
+  }
+
+\tl_new:N \g__chemmacros_reaction_description_tl
+
+\cs_new_protected:Npn \chemmacros_add_reaction_description:n #1
+  {
+    \tl_if_blank:nF { #1 }
+      { \tl_gset:Nn \g__chemmacros_reaction_description_tl { : ~ #1 } }
+  }
+
+\NewDocumentCommand \AddRxnDesc { m }
+  { \chemmacros_add_reaction_description:n { #1 } }
+
+% define \listofreactions
+\tl_new:N  \l__chemmacros_reaction_lorname_tl
+\tl_new:N  \reactionlistname
+\tl_new:N  \l__chemmacros_reaction_heading_tl
+
+\cs_if_exist:NTF \chapter
+  { \tl_set:Nn \l__chemmacros_reaction_heading_tl { \chapter* } }
+  { \tl_set:Nn \l__chemmacros_reaction_heading_tl { \section* } }
+
+\tl_set:Nn \l__chemmacros_reaction_lorname_tl { \chemmacros_translate:n {reaction} }
+\tl_set:Nn \reactionlistname { \chemmacros_translate:n {list-of-reactions} }
+
+\cs_new:Npn \__chemmacros_reaction_heading:n #1
+  { \l__chemmacros_reaction_heading_tl { #1 } }
+\cs_generate_variant:Nn \__chemmacros_reaction_heading:n { V }
+
+\cs_new_protected:Npn \listofreactions
+  {
+    \__chemmacros_reaction_heading:V \reactionlistname
+    \@starttoc { lor }
+  }
+
+\cs_new_protected:Npn \l@reaction #1#2
+  { \@dottedtocline { 1 } { 1.5em } { 2.3em } { #1 } { #2 } }
+
+% create new tagform
+\newtagform {reaction} {\{} {\}}
+\newcounter {chemmacros_save_reaction}
+\newcounter {reaction}
+
+\cs_new_protected:Npn \__chemmacros_begin_reaction:
+  {
+    % create individual names for `hyperref':
+    \bool_if:NT \l__chemmacros_hyperref_bool
+      {
+        \cs_set:Npn \theHequation
+          { R . \theHsection . \arabic {reaction} }
+      }
+    % enable labelformat `reaction':
+    \bool_if:NT \l__chemmacros_varioref_bool
+      { \cs_set_eq:NN \p@equation \p@reaction }
+    \setcounter {chemmacros_save_reaction} { \value {equation} }
+    \setcounter {equation} { \value {reaction} }
+    \usetagform {reaction}
+  }
+
+% switch back to equation tags
+\cs_new_protected:Npn \__chemmacros_end_reaction:
+  {
+    \setcounter {reaction} { \value {equation} }
+    \setcounter {equation} { \value {chemmacros_save_reaction} }
+  }
+
+\tl_new:N \l__chemmacros_reactions_args_tl
+
+\cs_new_protected:Npn \__chemmacros_reactions_build_args:n #1
+  { \tl_put_right:Nn \l__chemmacros_reactions_args_tl { {## #1} } }
+
+\cs_new_protected:Npn \chemmacros_define_reaction:nnn #1#2#3
+  {
+    \int_compare:nNnT {#3+0} > {0}
+      {
+        \tl_clear:N \l__chemmacros_reactions_args_tl
+        \int_step_function:nnnN {2} {1} {#3+1} \__chemmacros_reactions_build_args:n
+      }
+    \chemmacros_reaction_env:nnnV {#1} {#2} {#3} \l__chemmacros_reactions_args_tl
+  }
+
+% #1: chem
+% #2: math
+% #3: args number
+% #4: argument list ({#2}{#3}...)
+\cs_new_protected:Npn \chemmacros_reaction_env:nnnn #1#2#3#4
+  {
+    \exp_args:Nnx \DeclareDocumentEnvironment {#1} { O{} \prg_replicate:nn {#3+0} {m} }
+      {
+        \chemmacros_add_reaction_description:n {##1}
+        \__chemmacros_begin_reaction:
+        \chemmacros_reaction_read:nnw {#2} {#4}
+      }
+      { \__chemmacros_end_reaction: }
+  }
+\cs_generate_variant:Nn \chemmacros_reaction_env:nnnn {nnnV}
+  
+\cs_new_protected:Npn \chemmacros_reaction_read:nnw #1#2#3 \end
+  {
+    \begin{#1}#2
+      \chemformula_ch:nn {} {#3}
+    \end{#1}
+    \end
+  }
+
+\chemmacros_new_environment_macroset:nnn {Reaction} {mO{}m}
+  { \chemmacros_define_reaction:nnn {#1} {#3} {#2} }
+
+\NewChemReaction {reaction}   {equation}
+\NewChemReaction {reaction*}  {equation*}
+\NewChemReaction {reactions}  {align}
+\NewChemReaction {reactions*} {align*}
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.redox.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.redox.code.tex
new file mode 100644
index 00000000000..1b9ace3108a
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.redox.code.tex
@@ -0,0 +1,403 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `redox'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{redox}{2015/09/11 oxidation numbers, redox reactions}
+
+\chemmacros_load_modules:n {tikz,xfrac}
+
+\RequirePackage{mathtools,relsize}
+
+\msg_new:nnn {chemmacros} {redox}
+  { \token_to_str:N #1 \c_space_tl : ~ #2 ~ \msg_line_context: . }
+
+
+% --------------------------------------------------------------------------
+% oxidation numbers
+% \ox{<number>,<atom>}
+\bool_new:N \l__chemmacros_ox_sign_bool
+\bool_new:N \l__chemmacros_ox_integer_bool
+\bool_new:N \l__chemmacros_ox_explicit_sign_bool
+\bool_new:N \l__chemmacros_ox_format_roman_bool
+\bool_new:N \l__chemmacros_ox_decimal_marker_comma_bool
+\bool_new:N \l__chemmacros_ox_parse_bool
+\bool_new:N \l__chemmacros_ox_side_bool
+\bool_new:N \l__chemmacros_ox_super_bool
+\bool_new:N \l__chemmacros_ox_top_bool
+\bool_new:N \l__chemmacros_ox_align_center_bool
+
+\int_new:N \l__chemmacros_ox_number_int
+\fp_new:N  \l__chemmacros_ox_number_fp
+
+\cs_new_protected:Npn \__chemmacros_ox_process_number:n #1
+  {
+    \bool_if:NTF \l__chemmacros_ox_parse_bool
+      {
+        \tl_if_in:nnTF {#1} { / }
+          { \__chemmacros_ox_fraction:w #1 \q_stop }
+          {
+            \__chemmacros_ox_sign:n  {#1}
+            \__chemmacros_ox_value:n {#1}
+          }
+      }
+      {#1}
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_fraction:w #1/#2 \q_stop
+  {
+    \group_begin:
+      \bool_set_false:N \l__chemmacros_ox_format_roman_bool
+      \__chemmacros_ox_sign:n {#1}
+      \bool_if:NTF \l__chemmacros_ox_side_bool
+        { \chemmacros_ox_text_frac:nn }
+        { \chemmacros_ox_super_frac:nn }
+        { \__chemmacros_ox_value:n {#1} }
+        {#2}
+    \group_end:
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_sign:n #1
+  {
+    \bool_if:nT
+      {
+        \fp_compare_p:n { #1 > 0 } &&
+        \l__chemmacros_ox_explicit_sign_bool
+      }
+      { \c_math_toggle_token + \c_math_toggle_token }
+    \bool_if:nT
+      {
+        \fp_compare_p:n { #1 = 0 } &&
+        \l__chemmacros_ox_explicit_sign_bool
+      }
+      { \c_math_toggle_token \pm \c_math_toggle_token }
+    \fp_compare:nT { #1 < 0 }
+      { \c_math_toggle_token - \c_math_toggle_token }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_value:n #1
+  {
+    \fp_set:Nn \l__chemmacros_ox_number_fp { abs(#1) }
+    \__chemmacros_ox_is_integer:n { \l__chemmacros_ox_number_fp }
+    \bool_if:NTF \l__chemmacros_ox_format_roman_bool
+      { \__chemmacros_fp_to_Roman:n { \l__chemmacros_ox_number_fp } }
+      {
+        \bool_if:NTF \l__chemmacros_ox_integer_bool
+          {
+            \c_math_toggle_token
+              \__chemmacros_fp_to_arabic:n { \l__chemmacros_ox_number_fp }
+            \c_math_toggle_token
+          }
+          {
+            \c_math_toggle_token
+              \fp_use:N \l__chemmacros_ox_number_fp
+            \c_math_toggle_token
+          }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_is_integer:n #1
+  {
+    \fp_compare:nNnTF {#1} = { round((#1) + 1 , 0 ) - 1 }
+      { \bool_set_true:N \l__chemmacros_ox_integer_bool }
+      {
+        \bool_set_false:N \l__chemmacros_ox_integer_bool
+        \bool_set_false:N \l__chemmacros_ox_format_roman_bool
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_fp_to_Roman:n #1
+  {
+    \group_begin:
+      \fp_compare:nNnTF {#1} = { 0 }
+        {0}
+        { \int_to_Roman:n { \fp_to_int:n {#1} } }
+    \group_end:
+  }
+
+\cs_new_protected:Npn \__chemmacros_fp_to_arabic:n #1
+  {
+    \group_begin:
+      \bool_if:NTF \l__chemmacros_ox_decimal_marker_comma_bool
+        {
+          \tl_set:Nx \l__chemmacros_tmpa_tl { \fp_to_decimal:n {#1} }
+          \tl_replace_once:Nnn \l__chemmacros_tmpa_tl {.} { {,} }
+          \tl_use:N \l__chemmacros_tmpa_tl
+        }
+        { \fp_to_decimal:n {#1} }
+    \group_end:
+  }
+
+\tl_new:N \l__chemmacros_ox_side_connect_tl
+
+\cs_new_protected:Npn \__chemmacros_ox_write:nn #1#2
+  {
+    \tl_if_blank:nT {#1}
+      { \msg_error:nnn {chemmacros} {redox} {\ox} {oxidation~number~missing} }
+    \tl_if_blank:nT {#2}
+      { \msg_error:nnn {chemmacros} {redox} {\ox} {oxidation-atom~missing} }
+    \hbox_set:Nn \l__chemmacros_tmpa_box
+      {
+        \chemmacros_text:n
+          { \relsize {-3} \__chemmacros_ox_process_number:n {#1} }
+      }
+    \hbox_set:Nn \l__chemmacros_tmpb_box { \chemmacros_chemformula:n {#2} }
+    \chemmacros_math:n
+      {
+        \bool_if:NT \l__chemmacros_ox_super_bool
+          {
+            \box_use:N \l__chemmacros_tmpb_box
+            \c_math_superscript_token { \box_use:N \l__chemmacros_tmpa_box }
+          }
+        \bool_if:NT \l__chemmacros_ox_side_bool
+          {
+            \chemmacros_text:n
+              {
+                \box_use:N \l__chemmacros_tmpb_box
+                \tl_use:N \l__chemmacros_ox_side_connect_tl
+                ( \__chemmacros_ox_process_number:n {#1} )
+              }
+          }
+        \bool_if:NT \l__chemmacros_ox_top_bool
+          {
+            \bool_if:NF \l__chemmacros_ox_align_center_bool
+              { 
+                \hbox_set_to_wd:Nnn \l__chemmacros_tmpa_box
+                  { \box_wd:N \l__chemmacros_tmpb_box }
+                  { \rlap { \hbox_unpack:N \l__chemmacros_tmpa_box } \hfil }
+              }
+            \overset
+              {
+                \bool_if:NTF \l__chemmacros_ox_align_center_bool
+                  { \clap }
+                  { \use:n }
+                { \box_use:N \l__chemmacros_tmpa_box }
+              }
+              { \box_use:N \l__chemmacros_tmpb_box }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_top:
+  {
+    \bool_set_true:N  \l__chemmacros_ox_top_bool
+    \bool_set_false:N \l__chemmacros_ox_super_bool
+    \bool_set_false:N \l__chemmacros_ox_side_bool
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_super:
+  {
+    \bool_set_false:N \l__chemmacros_ox_top_bool
+    \bool_set_true:N  \l__chemmacros_ox_super_bool
+    \bool_set_false:N \l__chemmacros_ox_side_bool
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_side:
+  {
+    \bool_set_false:N \l__chemmacros_ox_top_bool
+    \bool_set_false:N \l__chemmacros_ox_super_bool
+    \bool_set_true:N  \l__chemmacros_ox_side_bool
+  }
+
+\keys_define:nn {chemmacros/redox}
+  {
+    pos            .choice: ,
+    pos / top      .code:n     = \__chemmacros_ox_pos_top: ,
+    pos / super    .code:n     = \__chemmacros_ox_pos_super: ,
+    pos / side     .code:n     = \__chemmacros_ox_pos_side: ,
+    pos            .initial:n  = super ,
+    side-connect   .tl_set:N   = \l__chemmacros_ox_side_connect_tl ,
+    side-connect   .initial:n  = \, ,
+    text-frac      .code:n     =
+      \cs_set_protected:Npn \chemmacros_ox_text_frac:nn ##1##2 {#1} ,
+    text-frac      .initial:n  = \chemfrac[text]{#1}{#2} ,
+    super-frac     .code:n     =
+      \cs_set_protected:Npn \chemmacros_ox_super_frac:nn ##1##2 {#1} ,
+    super-frac     .initial:n  = \chemfrac[superscript]{#1}{#2} ,
+    roman          .bool_set:N = \l__chemmacros_ox_format_roman_bool ,
+    roman          .default:n  = true ,
+    roman          .initial:n  = true ,
+    parse          .bool_set:N = \l__chemmacros_ox_parse_bool ,
+    parse          .default:n  = true ,
+    parse          .initial:n  = true ,
+    explicit-sign  .bool_set:N = \l__chemmacros_ox_explicit_sign_bool ,
+    explicit-sign  .default:n  = true ,
+    decimal-marker .choice: ,
+    decimal-marker / comma .code:n =
+      { \bool_set_true:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
+    decimal-marker / point .code:n =
+      { \bool_set_false:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
+    decimal-marker .initial:n = point ,
+    align          .choice: ,
+    align / center .code:n    =
+      \bool_set_true:N \l__chemmacros_ox_align_center_bool ,
+    align / right  .code:n    =
+      \bool_set_false:N \l__chemmacros_ox_align_center_bool ,
+    align          .initial:n = center
+  }
+
+% \ox[<keyval>]{<num>,<atom>}
+% \ox*[<keyval>]{<num>,<atom>} => always number on the top
+\cs_new_protected:Npn \chemmacros_ox:nnnn #1#2#3#4
+  {
+    \group_begin:
+      \keys_set:nn {chemmacros/redox} {#2}
+      \tl_if_blank:nF {#1} { \__chemmacros_ox_pos_top: }
+      \__chemmacros_ox_write:nn {#3} {#4}
+    \group_end:
+  }
+
+\NewDocumentCommand \ox { sO{}>{\SplitArgument{1}{,}}m }
+  {
+    \IfBooleanTF {#1}
+      { \chemmacros_ox:nnnn {#1} {#2} #3 }
+      { \chemmacros_ox:nnnn {  } {#2} #3 }
+  }
+
+% ---------------------------------------------------------------------------
+% redox reactions
+\tl_new:N   \l__chemmacros_redox_begin_tl
+\tl_new:N   \l__chemmacros_redox_end_tl
+\tl_new:N   \l__chemmacros_redox_tikz_tl
+\tl_new:N   \l__chemmacros_redox_shift_tl
+\tl_new:N   \l__chemmacros_redox_anchor_tl
+\tl_new:N   \l__chemmacros_redox_side_tl
+
+\fp_new:N   \l__chemmacros_redox_shift_fp
+
+\dim_new:N  \l__chemmacros_redox_sep_dim
+\dim_new:N  \l__chemmacros_redox_sep_default_dim
+\dim_set:Nn \l__chemmacros_redox_sep_default_dim {.2em}
+\dim_new:N  \l__chemmacros_redox_dist_dim
+\dim_set:Nn \l__chemmacros_redox_dist_dim {.6em}
+
+% place and name nodes:
+% \OX{<name>,<atom>}
+\NewDocumentCommand \OX { >{\SplitArgument{1}{,}}m }
+  { \chemmacros_redox_partner:nn #1 }
+
+\cs_new_protected:Npn \chemmacros_redox_partner:nn #1#2
+  {
+    \chemmacros_tex_if:nnTF {measuring@} {}
+      {
+        \group_begin:
+          \tikz[baseline=(#1.base)] { \node [inner~sep=0pt] (#1) {#2} ; }
+        \group_end:
+      }
+      {
+        \tl_if_blank:nT {#1}
+          { \msg_error:nnnn {chemmacros} {redox} {\OX} {node~name~missing} }
+        \tl_if_blank:nT {#2}
+          { \msg_error:nnnn {chemmacros} {redox} {\OX} {atom~missing} }
+        \tikz[baseline=(#1.base),remember~picture]
+          { \node [inner~sep=0pt] (#1) {#2} ; }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_redox_coordinates:nn #1#2
+  {
+    \tl_set:Nn \l__chemmacros_redox_begin_tl {#1}
+    \tl_set:Nn \l__chemmacros_redox_end_tl   {#2}
+  }
+
+\cs_new_protected:Npn \chemmacros_redox:nnnnn #1#2#3#4#5
+  {
+    \tl_clear:N \l__chemmacros_redox_begin_tl
+    \tl_clear:N \l__chemmacros_redox_end_tl
+    \tl_clear:N \l__chemmacros_redox_tikz_tl
+    \__chemmacros_redox_coordinates:nn {#1} {#2}
+    \tl_if_blank:nF {#3}
+      { \tl_set:Nn \l__chemmacros_redox_tikz_tl {#3} }
+    \tl_if_blank:nTF {#4}
+      {
+        \fp_set:Nn \l__chemmacros_redox_shift_fp  {1}
+        \tl_set:Nn \l__chemmacros_redox_anchor_tl {above}
+        \tl_set:Nn \l__chemmacros_redox_side_tl   {north}
+        \dim_set_eq:NN
+          \l__chemmacros_redox_sep_dim
+          \l__chemmacros_redox_sep_default_dim
+      }
+      {
+        \fp_compare:nNnTF {#4} < {0}
+          {
+            \tl_set:Nn \l__chemmacros_redox_anchor_tl {below}
+            \tl_set:Nn \l__chemmacros_redox_side_tl   {south}
+            \exp_args:NNo \dim_set:Nn \l__chemmacros_redox_sep_dim
+              { - \l__chemmacros_redox_sep_default_dim }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_redox_anchor_tl {above}
+            \tl_set:Nn \l__chemmacros_redox_side_tl   {north}
+            \dim_set_eq:NN
+              \l__chemmacros_redox_sep_dim
+              \l__chemmacros_redox_sep_default_dim
+          }
+        \fp_set:Nn \l__chemmacros_redox_shift_fp {#4}
+      }
+      \tl_set:Nx \l__chemmacros_redox_shift_tl
+        { \fp_to_decimal:N \l__chemmacros_redox_shift_fp }
+    \tikz[remember~picture,overlay]
+      {
+        \chemmacros_tikz_draw:x { \exp_not:V \l__chemmacros_redox_tikz_tl }
+        ($
+          (\l__chemmacros_redox_begin_tl .
+          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
+        $)
+        -- 
+        ++(0,\l__chemmacros_redox_shift_tl * \l__chemmacros_redox_dist_dim) -|
+        node [pos=.25,\l__chemmacros_redox_anchor_tl] { {#5} }
+        ($
+          (\l__chemmacros_redox_end_tl .
+          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
+        $) ;
+      }
+  }
+
+\NewDocumentCommand \redox { >{\SplitArgument{1}{,}}r()ooG{} }
+  {
+    \IfNoValueT {#1}
+      {
+        \msg_error:nnnn {chemmacros} {redox} {\redox}
+          {You~need~to~specify~coordinates}
+      }
+    \IfNoValueTF {#2}
+      { \chemmacros_redox:nnnnn #1 { } { } {#4} }
+      {
+        \IfNoValueTF {#3}
+          { \chemmacros_redox:nnnnn #1 {#2} {  } {#4} }
+          { \chemmacros_redox:nnnnn #1 {#2} {#3} {#4} }
+      }
+  }
+
+% redox-keys
+\keys_define:nn {chemmacros/redox}
+  {
+    dist .dim_set:N = \l__chemmacros_redox_dist_dim ,
+    dist .initial:n = {.6em} ,
+    sep  .dim_set:N = \l__chemmacros_redox_sep_default_dim ,
+    sep  .initial:n = {.2em}
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.scheme.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.scheme.code.tex
new file mode 100644
index 00000000000..5963e3e2260
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.scheme.code.tex
@@ -0,0 +1,213 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `scheme'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{scheme}{2015/06/09 a scheme floating environment}
+
+\RequirePackage {chemnum}
+
+\bool_new:N \l__chemmacros_float_def_bool
+\tl_new:N   \l__chemmacros_float_method_tl
+\seq_new:N  \l__chemmacros_float_methods_seq
+\prop_new:N \l__chemmacros_float_methods_prop
+\prop_new:N \l__chemmacros_float_definitions_prop
+
+% --------------------------------------------------------------------------
+% #1: name
+% #2: check
+\cs_new_protected:Npn \chemmacros_define_float_method:nnn #1#2#3
+  {
+    \seq_put_right:Nn \l__chemmacros_float_methods_seq {#1}
+    \prop_put:Nnn \l__chemmacros_float_methods_prop {#1} {#2}
+    \prop_put:Nnn \l__chemmacros_float_definitions_prop {#1}
+      { \cs_set_protected:Npn \__chemmacros_define_float:n ##1 {#3} }
+  }
+
+% the order in which the methods are defined determines in which order the
+% methods will be checked at begin document:
+\chemmacros_define_float_method:nnn {KOMA}
+  { \cs_if_exist_p:N \KOMAClassName }
+  {
+    \DeclareNewTOC[
+      type  = #1 ,
+      types = #1s ,
+      float ,
+      name = \chemmacros_translate:n {#1-name} ,
+      listname = {\exp_not:N \chemmacros_translate:n {#1-list}}
+    ]{los}
+  }
+
+\chemmacros_define_float_method:nnn {memoir}
+  { \chemmacros_if_class_loaded_p:n {memoir} }
+  {
+    \newfloat [chapter] {scheme} {los} {\chemmacros_translate:n {#1-name}}
+    \cs_set:Npn \thescheme {\thechapter.\@arabic\c@scheme}
+    \newlistof {listofschemes} {los} {\chemmacros_translate:n {#1-list}}
+    \newlistentry [chapter] {scheme} {los} {0}
+    \cftsetindents {scheme} {0em} {2.3em}
+    \tl_put_right:Nn \@memfront@floats
+      { \counterwithout {scheme} {chapter} }
+    \tl_put_right:Nn \@memmain@floats
+      { \counterwithin {scheme} {chapter} }
+    \tl_put_right:Nn \@memback@floats
+      {
+        \counterwithin {scheme} {chapter}
+        \setcounter {scheme} {0}
+      }
+    \chemmacros_tex_if:nT {artopt}
+      { \counterwithout {scheme} {chapter} }
+  }
+
+\chemmacros_define_float_method:nnn {tocbasic}
+  { \chemmacros_if_package_loaded_p:n {tocbasic} }
+  {
+    \DeclareNewTOC[
+      type  = #1 ,
+      types = #1s ,
+      float ,
+      name = \chemmacros_translate:n {#1-name} ,
+      listname = {\exp_not:N \chemmacros_translate:n {#1-list}}
+    ]{los}
+  }
+
+\chemmacros_define_float_method:nnn {newfloat}
+  { \chemmacros_if_package_loaded_p:n {newfloat} }
+  {
+    \DeclareFloatingEnvironment[{
+      fileext = los ,
+      listname = {\exp_not:N \chemmacros_translate:n {#1-list}} ,
+      name = #2
+    }]{#1}
+  }
+
+\chemmacros_define_float_method:nnn {float}
+  { \chemmacros_if_package_loaded_p:n {float} }
+  {
+    \newfloat {scheme} {htp} {los}
+    \floatname {scheme} {\chemmacros_translate:n {#1-name}}
+    \cs_new_protected:Npn \listofschemes
+      { \listof {scheme} {\chemmacros_translate:n {#1-list}} }
+  }
+
+% --------------------------------------------------------------------------
+% checks if one of the above defined methods is active.  The first one found
+% will be used.
+\cs_new_protected:Npn \chemmacros_check_float_method:n #1
+  {
+    \prop_get:NnNT \l__chemmacros_float_methods_prop {#1}
+      \l__chemmacros_tmpa_tl
+    \bool_if:nT
+      { !\l__chemmacros_float_def_bool && \l__chemmacros_tmpa_tl }
+      {
+        \bool_set_true:N \l__chemmacros_float_def_bool
+        \tl_set:Nn \l__chemmacros_float_method_tl {#1}
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_check_float_methods:
+  {
+    \seq_map_function:NN
+      \l__chemmacros_float_methods_seq
+      \chemmacros_check_float_method:n
+  }
+
+\AtBeginDocument
+  {
+    \chemmacros_check_float_methods:
+    \chemmacros_define_float:n {scheme}
+  }
+
+% --------------------------------------------------------------------------
+% #1: env name
+\cs_new_protected:Npn \chemmacros_define_float:n #1
+  {
+    \bool_if:nT
+      { !\cs_if_exist_p:c {#1} && !\cs_if_exist_p:c {#1} }
+      {
+        \bool_if:NTF \l__chemmacros_float_def_bool
+          {
+            \prop_get:NVN \l__chemmacros_float_definitions_prop
+              \l__chemmacros_float_method_tl
+              \l__chemmacros_tmpa_tl
+            \tl_use:N \l__chemmacros_tmpa_tl
+            \__chemmacros_define_float:n {#1}
+          }
+          {
+            \newcounter {scheme}
+            \cs_set:Npn \thescheme      {\@arabic\c@scheme}
+            \cs_new:Npn \fps@scheme     {tbp}
+            \cs_new:Npn \ftype@scheme   {8}
+            \cs_new:Npn \ext@scheme     {los}
+            \cs_new:Npn \fnum@scheme    {\schemename\nobreakspace\thescheme}
+            \cs_new:Npn \schemename     {\chemmacros_translate:n {#1-name}}
+            \cs_new:Npn \listschemename {\chemmacros_translate:n {#1-list}}
+            \newenvironment {scheme}
+              {\@float{scheme}}
+              {\end@float}
+            \newenvironment {scheme*}
+              {\@dblfloat{scheme}}
+              {\end@dblfloat}
+            \bool_if:nTF
+              {
+                \chemmacros_if_class_loaded_p:n {book} ||
+                \chemmacros_if_class_loaded_p:n {report}
+              }
+              {
+                \cs_new_protected:Npn \listofschemes
+                  {
+                    \chemmacros_tex_if:nTF {@twocolumn}
+                      { \@restonecoltrue\onecolumn }
+                      { \@restonecolfalse }
+                    \chapter* {\listschemename}
+                    \@mkboth
+                      {\MakeUppercase\listschemename}
+                      {\MakeUppercase\listschemename}
+                    \@starttoc {los}
+                    \chemmacros_tex_if:nT {@restonecol}
+                      { \twocolumn }
+                  }
+              }
+              {
+                \cs_new_protected:Npn \listofschemes
+                  {
+                     \section* {\listschemename}
+                     \@mkboth
+                       {\MakeUppercase\listschemename}
+                       {\MakeUppercase\listschemename}
+                    \@starttoc {los}
+                  }
+              }
+            \cs_new_eq:NN \l@scheme \l@figure
+            \chemmacros_if_package_loaded:nT
+              {floatrow}
+              { \flrow@restyle {scheme} }
+          }
+      }
+    \cs_set:Npn \schemename     {\chemmacros_translate:n {#1-name}}
+    \cs_set:Npn \listschemename {\chemmacros_translate:n {#1-list}}
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.spectroscopy.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.spectroscopy.code.tex
new file mode 100644
index 00000000000..e5bcb407e10
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.spectroscopy.code.tex
@@ -0,0 +1,469 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `spectroscopy'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{spectroscopy}{2015/06/09 environment for spectroscopic data}
+
+\chemmacros_load_modules:n {chemformula}
+\RequirePackage{siunitx}
+
+% spectroscopy
+\tl_new:N  \g__chemmacros_nmr_isotope_tl
+\tl_new:N  \l__chemmacros_nmr_isotope_default_tl
+\tl_set:Nn \l__chemmacros_nmr_isotope_default_tl { 1 }
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_pre_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_pre_tl { ( }
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_post_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_post_tl { ) }
+\tl_new:N  \l__chemmacros_nmr_coupling_bonds_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_bonds_pre_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_pre_tl { }
+\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_post_tl { \! }
+\tl_new:N  \l__chemmacros_nmr_coupling_symbol_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_symbol_tl { J }
+\tl_new:N  \g__chemmacros_nmr_element_coupled_tl
+\tl_new:N  \g__chemmacros_nmr_element_tl
+\tl_new:N  \l__chemmacros_nmr_element_default_tl
+\tl_set:Nn \l__chemmacros_nmr_element_default_tl { H }
+\tl_new:N  \l__chemmacros_nmr_format_tl
+\tl_new:N  \l__chemmacros_nmr_delta_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_unit_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_unit_tl { \hertz }
+\tl_new:N  \l__chemmacros_nmr_unit_tl
+\tl_set:Nn \l__chemmacros_nmr_unit_tl { \mega\hertz }
+\tl_new:N  \l__chemmacros_nmr_list_setup_tl
+\tl_set:Nn \l__chemmacros_nmr_list_setup_tl
+  {
+    \topsep\z@skip \partopsep\z@skip 
+    \itemsep\z@ \parsep\z@ \itemindent\z@
+    \leftmargin\z@
+  }
+\tl_new:N  \l__chemmacros_nmr_position_tl
+\tl_new:N  \l__chemmacros_nmr_element_method_connector_tl
+\tl_set:Nn \l__chemmacros_nmr_element_method_connector_tl {-}
+\tl_new:N  \l__chemmacros_nmr_method_tl
+\tl_set:Nn \l__chemmacros_nmr_method_tl {NMR}
+
+\bool_new:N      \l__chemmacros_nmr_coupling_nuclei_sub_bool
+\bool_new:N      \l__chemmacros_nmr_frequency_bool
+\bool_new:N      \l__chemmacros_nmr_solvent_bool
+\bool_new:N      \l__chemmacros_nmr_delimiters_bool
+\bool_new:N      \l__chemmacros_nmr_comma_bool
+\bool_new:N      \l__chemmacros_nmr_inner_bool
+\bool_new:N      \l__chemmacros_nmr_position_side_bool
+\bool_new:N      \l__chemmacros_nmr_parse_bool
+\bool_set_true:N \l__chemmacros_nmr_parse_bool
+\bool_new:N      \l__chemmacros_nmr_list_bool
+\bool_new:N      \l__chemmacros_nmr_use_equal_bool
+\bool_new:N      \l__chemmacros_nmr_custom_command_active_bool
+\bool_new:N      \l__chemmacros_nmr_custom_command_used_bool
+
+\cs_new_protected:Npn \__chemmacros_nmr_nucleus:nn #1#2
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl {#1}
+    \tl_if_in:nnTF {#2} {[} % ]
+      { \__chemmacros_nmr_element:w #2 \q_stop }
+      {
+        \tl_gset:No \g__chemmacros_nmr_element_tl {#2}
+        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
+      }
+  }
+\cs_generate_variant:Nn \__chemmacros_nmr_nucleus:nn { VV }
+
+\cs_new_protected:Npn \__chemmacros_nmr_nucleus:w #1,#2 \q_stop
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl {#1}
+    \tl_if_in:nnTF {#2} {[} % ]
+      { \__chemmacros_nmr_element:w #2 \q_stop }
+      {
+        \tl_gset:No \g__chemmacros_nmr_element_tl {#2}
+        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_element:w #1[#2] \q_stop
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_element_tl {#1}
+    \tl_gset:Nn \g__chemmacros_nmr_element_coupled_tl {#2}
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_default_nucleus:w #1,#2 \q_stop
+  {
+    \tl_set:Nn \l__chemmacros_nmr_isotope_default_tl {#1}
+    \tl_set:Nn \l__chemmacros_nmr_element_default_tl {#2}
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_base:nn #1#2
+  {
+    \tl_if_blank:VF \g__chemmacros_nmr_element_coupled_tl
+      {
+        \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl { \{ }
+        \tl_put_right:Nn \g__chemmacros_nmr_element_coupled_tl { \} }
+      }
+    \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl {#2}
+    \chemmacros_chemformula:n { ^{#1} }
+    \bool_if:NTF \l__chemmacros_nmr_parse_bool
+      { \chemformula_ch:nV {} \g__chemmacros_nmr_element_coupled_tl }
+      { \chemmacros_chemformula:V \g__chemmacros_nmr_element_coupled_tl }
+    \tl_use:N \l__chemmacros_nmr_element_method_connector_tl
+    \tl_use:N \l__chemmacros_nmr_method_tl
+  }
+\cs_generate_variant:Nn \__chemmacros_nmr_base:nn { VV }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency:n #1
+  {
+    \tl_if_in:nnTF {#1} {,}
+      { \__chemmacros_nmr_frequency_aux_i:w #1 \q_stop }
+      { \__chemmacros_nmr_frequency_aux_ii:n {#1} }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_i:w #1,#2 \q_stop
+  { \SI {#1} {#2} }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_ii:n #1
+  { \SI {#1} { \tl_use:N \l__chemmacros_nmr_unit_tl } }
+
+\cs_new_eq:NN \__chemmacros_nmr_number:n \use:n
+\cs_new_eq:NN \__chemmacros_nmr_position:n \use:n
+
+\keys_define:nn { chemmacros / spectroscopy }
+  {
+    unit          .tl_set:N      = \l__chemmacros_nmr_unit_tl ,
+    unit          .default:n     = \mega\hertz ,
+    nucleus       .code:n        =
+      { \__chemmacros_nmr_default_nucleus:w #1 \q_stop } ,
+    nucleus       .default:n     = {1,H} ,
+    format        .tl_set:N      = \l__chemmacros_nmr_format_tl ,
+    method        .tl_set:N      = \l__chemmacros_nmr_method_tl ,
+    connector     .tl_set:N      = \l__chemmacros_nmr_element_method_connector_tl ,
+    pos-number    .choice: ,
+    pos-number / sub  .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl {_}
+      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
+    pos-number / super .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl {^}
+      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
+    pos-number / side .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl {-}
+      \bool_set_true:N \l__chemmacros_nmr_position_side_bool ,
+    coupling-unit .tl_set:N   = \l__chemmacros_nmr_coupling_unit_tl ,
+    coupling-pos  .choice: ,
+    coupling-pos / sub .code:n =
+      \bool_set_true:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
+    coupling-pos / side .code:n =
+      \bool_set_false:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
+    coupling-nuclei-pre  .tl_set:N =
+      \l__chemmacros_nmr_coupling_nuclei_pre_tl ,
+    coupling-nuclei-post .tl_set:N =
+      \l__chemmacros_nmr_coupling_nuclei_post_tl ,
+    coupling-bonds-pre   .tl_set:N =
+      \l__chemmacros_nmr_coupling_bonds_pre_tl ,
+    coupling-bonds-post  .tl_set:N =
+      \l__chemmacros_nmr_coupling_bonds_post_tl ,
+    coupling-symbol .tl_set:N    =
+      \l__chemmacros_nmr_coupling_symbol_tl ,
+    atom-number-cs .code:n       =
+      \cs_set_eq:NN \__chemmacros_nmr_number:n #1 ,
+    coupling-pos-cs .code:n      =
+      \cs_set_eq:NN \__chemmacros_nmr_position:n #1 ,
+    parse         .bool_set:N    = \l__chemmacros_nmr_parse_bool ,
+    delta         .code:n        =
+      \tl_set:Nn \l__chemmacros_nmr_delta_tl {\,#1} ,
+    list          .bool_set:N    = \l__chemmacros_nmr_list_bool ,
+    list          .default:n     = true ,
+    list-setup    .tl_set:N      = \l__chemmacros_nmr_list_setup_tl ,
+    use-equal     .bool_set:N    = \l__chemmacros_nmr_use_equal_bool ,
+    use-equal     .default:n     = true
+  }
+
+\cs_new_protected:Npn \chemmacros_define_nmr:Nn #1#2
+  {
+    \cs_if_exist:NTF #1
+      {
+        \RenewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+      {
+        \NewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+  }
+
+\chemmacros_new_macroset:nnn {NMR} {mm} { \chemmacros_define_nmr:Nn #1 {#2} }
+
+\NewDocumentCommand \NMR { sG{}D(){}O{} }
+  {
+    \IfBooleanTF {#1}
+      { \chemmacros_nmr:nnnn {*} {#2} {#3} {#4} }
+      { \chemmacros_nmr:nnnn { } {#2} {#3} {#4} }
+  }
+
+\AtBeginDocument
+  {
+    % \NMR{<num>,<elem>}(<num>,<unit>)[<solvent>] ALL arguments are optional
+    % \NMR* same but without ": $\delta$" at end
+    \cs_new_protected:Npn \chemmacros_nmr:nnnn #1#2#3#4
+      {
+        \bool_if:NT \l__chemmacros_nmr_list_bool { \item \scan_stop: }
+        \group_begin:
+          \chemmacros_leave_vmode:
+          \bool_set_false:N \l__chemmacros_nmr_frequency_bool
+          \bool_set_false:N \l__chemmacros_nmr_solvent_bool
+          \tl_if_empty:nF {#3}
+            { \bool_set_true:N \l__chemmacros_nmr_frequency_bool }
+          \tl_if_empty:nF {#4}
+            { \bool_set_true:N \l__chemmacros_nmr_solvent_bool }
+          \bool_if:nT
+            {
+              \l__chemmacros_nmr_frequency_bool
+              ||
+              \l__chemmacros_nmr_solvent_bool
+            }
+            { \bool_set_true:N \l__chemmacros_nmr_delimiters_bool }
+          \bool_if:nT
+            {
+              \l__chemmacros_nmr_frequency_bool
+              &&
+              \l__chemmacros_nmr_solvent_bool
+            }
+            { \bool_set_true:N \l__chemmacros_nmr_comma_bool }
+          \tl_if_empty:nTF {#2}
+            {
+              \__chemmacros_nmr_nucleus:VV
+                \l__chemmacros_nmr_isotope_default_tl
+                \l__chemmacros_nmr_element_default_tl
+            }
+            { \__chemmacros_nmr_nucleus:w #2 \q_stop }
+          \mode_if_math:TF
+            {
+              \text
+                {
+                  \group_begin:
+                    \tl_use:N \l__chemmacros_nmr_format_tl
+                    \__chemmacros_nmr_base:VV
+                      \g__chemmacros_nmr_isotope_tl
+                      \g__chemmacros_nmr_element_tl
+                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                      { ~ ( }
+                    \bool_if:NT \l__chemmacros_nmr_frequency_bool
+                      { \__chemmacros_nmr_frequency:n {#3} }
+                    \bool_if:NT \l__chemmacros_nmr_comma_bool
+                      { , ~ }
+                    \bool_if:NT \l__chemmacros_nmr_solvent_bool
+                      { \chemmacros_chemformula:n {#4} }
+                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                      { ) }
+                    \tl_if_blank:nT {#1} {:~}
+                  \group_end:
+                }
+              \tl_if_blank:nT {#1}
+                {
+                  \delta
+                  \text { \l__chemmacros_nmr_delta_tl }
+                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool {=}
+                }
+            }
+            {
+              \group_begin:
+                \tl_use:N \l__chemmacros_nmr_format_tl
+                \__chemmacros_nmr_base:VV
+                  \g__chemmacros_nmr_isotope_tl
+                  \g__chemmacros_nmr_element_tl
+                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                  {~(}
+                \bool_if:NT \l__chemmacros_nmr_frequency_bool
+                  { \__chemmacros_nmr_frequency:n {#3} }
+                \bool_if:NT \l__chemmacros_nmr_comma_bool
+                  {,~}
+                \bool_if:NT \l__chemmacros_nmr_solvent_bool
+                  {
+                    \bool_if:NTF \l__chemmacros_nmr_parse_bool
+                      { \chemformula_ch:nn { } {#4} }
+                      {#4}
+                  }
+                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                  {)}
+                \tl_if_blank:nT {#1} {:}
+              \group_end:
+              \tl_if_blank:nT {#1}
+                {
+                  \tl_use:N \c_space_tl
+                  \c_math_toggle_token
+                    \delta
+                  \c_math_toggle_token
+                  \l__chemmacros_nmr_delta_tl
+                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool {~=}
+                }
+            }
+        \group_end:
+      }
+  }
+
+\NewDocumentCommand \chemmacros_data:w { smo }
+  {
+    \bool_if:NT \l__chemmacros_nmr_list_bool { \item }
+    {
+      \tl_use:N \l__chemmacros_nmr_format_tl #2
+      \IfNoValueF {#3} { ~ ( #3 ) }
+      \IfBooleanT {#1} { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { : } }
+    }
+    \IfBooleanF {#1} { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { ~ = } }
+  }
+
+\cs_new_protected:Npn \chemmacros_val:n #1
+  {
+    \tl_if_in:nnTF {#1} {--}
+      { \chemmacros_val_aux:w #1 \q_nil }
+      { \num {#1} }
+  }
+
+\cs_new_protected:Npn \chemmacros_val_aux:w #1--#2 \q_nil
+  { \numrange {#1} {#2} }
+
+\NewDocumentEnvironment {experimental} {o}
+  {
+    \group_begin:
+    \IfNoValueF {#1} { \keys_set:nn {chemmacros/spectroscopy} {#1} }
+    \bool_set_true:N \l__chemmacros_nmr_inner_bool
+    \cs_set_eq:NN \#    \chemmacros_nmr_number:n
+    \cs_set_eq:NN \pos  \chemmacros_nmr_position:n
+    \cs_set_eq:NN \J    \chemmacros_nmr_coupling:w
+    \cs_set_eq:NN \data \chemmacros_data:w
+    \cs_set_eq:NN \val  \chemmacros_val:n
+    \bool_if:NT \l__chemmacros_nmr_list_bool
+      { \list {} { \l__chemmacros_nmr_list_setup_tl } }
+  }
+  {
+    \bool_if:NT \l__chemmacros_nmr_list_bool
+      { \endlist }
+    \group_end:
+    \chemmacros_ignore_spaces:
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_number:n #1
+  {
+    \__chemmacros_nmr_number:n {#1} \,
+    \chemmacros_chemformula:V \g__chemmacros_nmr_element_tl
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_position:n #1
+  {
+    \chemmacros_chemformula:x
+      {
+        \exp_not:V \g__chemmacros_nmr_element_tl
+        \bool_if:NF \l__chemmacros_nmr_position_side_bool
+          {
+            \exp_not:V \l__chemmacros_nmr_position_tl
+            \exp_not:n { {#1} }
+          }
+      }
+    \bool_if:NT \l__chemmacros_nmr_position_side_bool
+      {
+        \tl_use:N \l__chemmacros_nmr_position_tl
+        \__chemmacros_nmr_position:n {#1}
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_coupling:w
+  {
+    \tl_clear:N \l__chemmacros_nmr_coupling_nuclei_tl
+    \tl_clear:N \l__chemmacros_nmr_coupling_bonds_tl
+    \peek_meaning:NTF (
+      { \__chemmacros_nmr_coupling:w }
+      { \__chemmacros_nmr_coupling_aux_i:w }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling:w (#1;#2)
+  {
+    \tl_set:Nn \l__chemmacros_nmr_coupling_bonds_tl
+      {
+        \l__chemmacros_nmr_coupling_bonds_pre_tl
+        #1
+        \l__chemmacros_nmr_coupling_bonds_post_tl
+      }
+    \bool_if:NTF \l__chemmacros_nmr_coupling_nuclei_sub_bool
+      {
+        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
+          {
+            \c_math_subscript_token
+              { \chemmacros_chemformula:n {#2} }
+          }
+      }
+      {
+        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
+          {
+            \l__chemmacros_nmr_coupling_nuclei_pre_tl
+            \chemmacros_chemformula:n {#2}
+            \l__chemmacros_nmr_coupling_nuclei_post_tl
+          }
+      }
+    \__chemmacros_nmr_coupling_aux_i:w
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_i:w
+  {
+    \peek_meaning:NTF [
+      { \__chemmacros_nmr_coupling_aux_ii:w }
+      { \__chemmacros_nmr_coupling_aux_iii:n }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_ii:w [#1]#2
+  {
+    \group_begin:
+      \sisetup
+        {
+          list-final-separator={,~},
+          list-pair-separator={,~},
+          list-units=single
+        }
+      \c_math_toggle_token
+        ^{ \l__chemmacros_nmr_coupling_bonds_tl }
+        \l__chemmacros_nmr_coupling_symbol_tl
+        \l__chemmacros_nmr_coupling_nuclei_tl = \SIlist {#2} {#1}
+      \c_math_toggle_token
+    \group_end:
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_iii:n #1
+  {
+    \group_begin:
+      \sisetup
+        {
+          list-final-separator={,~},
+          list-pair-separator={,~},
+          list-units=single
+        }
+      \c_math_toggle_token
+         ^{ \l__chemmacros_nmr_coupling_bonds_tl }
+         \l__chemmacros_nmr_coupling_symbol_tl
+         \l__chemmacros_nmr_coupling_nuclei_tl
+         = \exp_args:Nno \SIlist {#1} { \l__chemmacros_nmr_coupling_unit_tl }
+      \c_math_toggle_token
+    \group_end:
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.symbols.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.symbols.code.tex
new file mode 100644
index 00000000000..6482a78229c
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.symbols.code.tex
@@ -0,0 +1,89 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `symbols'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{symbols}{2015/06/09 symbols}
+
+\RequirePackage{amstext}
+
+% ---------------------------------------------------------------------------
+% transition state symbol
+\cs_new_protected:Npn \__chemmacros_transition_state:
+  {
+    \text
+      {
+        \skip_horizontal:n { .1ex }
+        \hbox_overlap_right:n
+          { \rule { .6ex } { 0pt } \rule { .05ex } { 1.3ex } }
+        \hbox_overlap_right:n { \rule [ .4ex ] { 1.3ex } { .05ex } }
+        \rule [ .85ex ] { 1.3ex } { .05ex }
+        \skip_horizontal:n { .1ex }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_transition_state:
+  {
+    \ensuremath
+      {
+        \mathchoice
+          { \displaystyle }
+          { \textstyle }
+          { \scriptstyle }
+          { \scriptscriptstyle }
+        \__chemmacros_transition_state:
+      }
+  }
+
+% \DeclareDocumentCommand?
+\cs_new_eq:NN \transitionstatesymbol \chemmacros_transition_state:
+
+% \standardstate as defined by the chemstyle package. Thanks to Joseph Wright
+% the `chemstyle' provides it with \providecommand so it doesn't matter which
+% package defines it first
+\ProvideDocumentCommand \standardstate {}
+  { { \ensuremath { \chemmacros_standardstate: } } }
+
+\cs_new_protected:Npn \chemmacros_standardstate:
+  { \mathpalette \chemmacros_standardstate_aux: \circ }
+
+\cs_new_protected:Npn \chemmacros_standardstate_aux: #1#2
+  {
+    \ooalign
+      {
+        \tex_hfil:D
+        \c_math_toggle_token #1- \c_math_toggle_token
+        \tex_hfil:D
+        \tex_cr:D
+        \tex_hfil:D
+        \c_math_toggle_token #1#2 \c_math_toggle_token
+        \tex_hfil:D
+        \tex_cr:D
+      }
+  }
+
+\cs_new_protected:Npn \changestate { \ensuremath { \mathop{} \! \chemDelta } }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.thermodynamics.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.thermodynamics.code.tex
new file mode 100644
index 00000000000..edde631c1ca
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.thermodynamics.code.tex
@@ -0,0 +1,143 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `thermodynamics'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{thermodynamics}{2015/06/09 thermodynamics}
+
+\RequirePackage {siunitx}
+
+\tl_new:N \l__chemmacros_state_pre_tl
+\tl_new:N \l__chemmacros_state_post_tl
+\tl_new:N \l__chemmacros_state_sp_left_tl
+\tl_new:N \l__chemmacros_state_sb_left_tl
+\tl_new:N \l__chemmacros_state_sp_right_tl
+\tl_new:N \l__chemmacros_state_sb_right_tl
+\tl_new:N \l__chemmacros_state_sb_pos_tl
+\tl_new:N \l__chemmacros_state_symbol_tl
+\tl_new:N \l__chemmacros_state_unit_tl
+
+\tl_set:Nn \l__chemmacros_state_pre_tl { \changestate }
+\tl_set:Nn \l__chemmacros_state_sp_right_tl { \standardstate }
+\tl_set:Nn \l__chemmacros_state_sb_pos_tl {left}
+
+\keys_define:nn {chemmacros/thermodynamics}
+  {
+    pre               .tl_set:N   = \l__chemmacros_state_pre_tl ,
+    post              .tl_set:N   = \l__chemmacros_state_post_tl ,
+    superscript-left  .tl_set:N   = \l__chemmacros_state_sp_left_tl ,
+    superscript-right .tl_set:N   = \l__chemmacros_state_sp_right_tl ,
+    superscript       .meta:n     = { superscript-right = #1 } ,
+    subscript-left    .tl_set:N   = \l__chemmacros_state_sb_left_tl ,
+    subscript-right   .tl_set:N   = \l__chemmacros_state_sb_right_tl ,
+    subscript         .meta:n     = { subscript-left = #1 } ,
+    unit              .tl_set:N   = \l__chemmacros_state_unit_tl ,
+    unit              .groups:n   = {variables}
+  }
+
+\cs_new_protected:Npn \chemmacros_state:nn #1#2
+  {
+    % pre (\Delta)
+    % post
+    % superscript-left
+    % superscript-right (\standardstate)
+    % subscript-left
+    % subscript-right
+    \group_begin:
+      \keys_set:nn {chemmacros/thermodynamics} {#1}
+      \ensuremath
+        {
+          \chemmacros_text:V \l__chemmacros_state_pre_tl
+          \c_math_superscript_token
+            { \chemmacros_text:V \l__chemmacros_state_sp_left_tl }
+          \c_math_subscript_token
+            { \chemmacros_text:V \l__chemmacros_state_sb_left_tl }
+          #2
+          \c_math_superscript_token
+            { \chemmacros_text:V \l__chemmacros_state_sp_right_tl }
+          \c_math_subscript_token
+            { \chemmacros_text:V \l__chemmacros_state_sb_right_tl }
+          \chemmacros_text:V \l__chemmacros_state_post_tl
+        }
+    \group_end:
+  }
+\cs_generate_variant:Nn \chemmacros_state:nn { nV }
+
+\DeclareDocumentCommand \state { O{}m }
+  { \chemmacros_state:nn {#1} {#2} }
+
+\cs_new_protected:Npn \chemmacros_declare_state:Nn #1#2
+  {
+    \keys_define:xn {chemmacros/thermodynamics/\chemmacros_remove_backslash:N #1}
+      {
+        pre               .meta:nn = {chemmacros/thermodynamics} { pre = ##1 } ,
+        post              .meta:nn = {chemmacros/thermodynamics} { post = ##1 } ,
+        superscript-left  .meta:nn = {chemmacros/thermodynamics} { superscript-left = ##1 } ,
+        superscript-right .meta:nn = {chemmacros/thermodynamics} { superscript-right = ##1 } ,
+        superscript       .meta:n  = { superscript-right = ##1 } ,
+        subscript-left    .meta:nn = {chemmacros/thermodynamics} { subscript-left = ##1 } ,
+        subscript-right   .meta:nn = {chemmacros/thermodynamics} { subscript-right = ##1 } ,
+        subscript         .meta:n     = { subscript-left = ##1 } ,
+        subscript-pos     .choices:nn =
+          { left , right }
+          { \tl_set_eq:NN \l__chemmacros_state_sb_pos_tl \l_keys_choice_tl } ,
+        symbol            .tl_set:N = \l__chemmacros_state_symbol_tl ,
+        unit              .tl_set:N = \l__chemmacros_state_unit_tl
+      }
+    \DeclareDocumentCommand #1 { sO{}D(){}m }
+      {
+        \group_begin:
+          \keys_set:xn {chemmacros/thermodynamics/\chemmacros_remove_backslash:N #1} {#2}
+          \tl_if_blank:nF {##3}
+            {
+              \keys_set:nx {chemmacros/thermodynamics}
+                { subscript-\l__chemmacros_state_sb_pos_tl = \exp_not:n {##3} }
+            }
+          \ensuremath
+            {
+              \chemmacros_state:nV {##2} \l__chemmacros_state_symbol_tl
+              \keys_set_groups:nnn {chemmacros/thermodynamics} {variables} {##2}
+              \IfBooleanF {##1} { = \SI {##4} { \l__chemmacros_state_unit_tl } }
+            }
+        \group_end:
+      }
+  }
+
+\chemmacros_new_macroset:nnn {State} {mm} { \chemmacros_declare_state:Nn #1 {#2} }
+
+% --------------------------------------------------------------------------
+% predefined:
+\NewChemState \enthalpy { symbol = H , unit = \kilo\joule\per\mole }
+\NewChemState \entropy  { symbol = S , unit = \joule\per\kelvin\per\mole , pre = }
+\NewChemState \gibbs    { symbol = G , unit = \kilo\joule\per\mole }
+
+\ChemCompatibilityTo{5.2}
+  \DeclareChemDeprecated \State    \state
+  \DeclareChemDeprecated \Enthalpy \enthalpy
+  \DeclareChemDeprecated \Entropy  \entropy
+  \DeclareChemDeprecated \Gibbs    \gibbs
+\EndChemCompatibility
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.tikz.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.tikz.code.tex
new file mode 100644
index 00000000000..9524d14d734
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.tikz.code.tex
@@ -0,0 +1,143 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `tikz'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule*{tikz}{2015/07/24 upright greek symbols}
+
+\RequirePackage{tikz}
+\usetikzlibrary{calc}%,arrows}
+
+\ExplSyntaxOn
+
+\tl_const:Nx \c_chemmacros_other_colon_tl { \token_to_str:N : }
+
+% --------------------------------------------------------------------------
+% TikZ drawings - helper macros
+\cs_new_protected:Npn \chemmacros_tikz_picture:nn #1#2
+  { \tikzpicture[{#1}] #2 \endtikzpicture }
+\cs_new_protected:Npn \chemmacros_tikz:nn #1#2           { \tikz[{#1}] {#2} }
+\cs_new_protected:Npn \chemmacros_tikz_draw:n #1         { \draw[{#1}] }
+\cs_new_protected:Npn \chemmacros_tikz_node:n #1         { \node[{#1}] }
+\cs_new_protected:Npn \chemmacros_tikz_shade:n #1        { \shade[{#1}] }
+\cs_new_protected:Npn \chemmacros_tikz_shadedraw:n #1    { \shadedraw[{#1}] }
+\cs_new_protected:Npn \chemmacros_tikz_node_in_draw:n #1 { node[{#1}] }
+
+\cs_generate_variant:Nn \chemmacros_tikz_picture:nn     { xn }
+\cs_generate_variant:Nn \chemmacros_tikz_draw:n         { x }
+\cs_generate_variant:Nn \chemmacros_tikz_node:n         { x }
+\cs_generate_variant:Nn \chemmacros_tikz_shade:n        { x }
+\cs_generate_variant:Nn \chemmacros_tikz_shadedraw:n    { x }
+\cs_generate_variant:Nn \chemmacros_tikz_node_in_draw:n { x }
+
+% --------------------------------------------------------------------------
+% arrow tips for electron movement
+\dim_new:N \l__chemmacros_el_length_dim
+
+% full tip for pairs
+\pgfarrowsdeclare { el } { el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { .3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto
+      { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { -.3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+
+% half tip on the left
+\pgfarrowsdeclare { left~el } { left~el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { .3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+
+% half tip in the right
+\pgfarrowsdeclare { right~el } { right~el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { -.3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.units.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.units.code.tex
new file mode 100644
index 00000000000..b6bbe6776ef
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.units.code.tex
@@ -0,0 +1,52 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `units'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{units}{2015/07/22 chemical units}
+
+\RequirePackage{siunitx}
+
+% --------------------------------------------------------------------------
+\DeclareSIUnit {\atm       } {atm}
+\DeclareSIUnit {\atmosphere} {atm}
+\DeclareSIUnit {\calory    } {cal}
+\DeclareSIUnit {\cal       } {cal}
+\DeclareSIUnit {\moLar     } {\mole\per\liter}
+\DeclareSIUnit {\MolMass   } {\gram\per\mole}
+\DeclareSIUnit {\normal    } {\textsc{n}}
+\DeclareSIUnit {\torr      } {torr}
+
+\AtBeginDocument
+  {
+    \chemmacros_if_package_loaded:nF {chemstyle}
+      {
+        \DeclareSIUnit {\cmc  } {\cubic\centi\metre}
+        \DeclareSIUnit {\molar} {\mole\per\cubic\deci\metre}
+        \DeclareSIUnit {\Molar} {\textsc{m}}
+      }
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.xfrac.code.tex b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.xfrac.code.tex
new file mode 100644
index 00000000000..3308b4c5d37
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.module.xfrac.code.tex
@@ -0,0 +1,137 @@
+% --------------------------------------------------------------------------
+%
+% the CHEMMACROS package -- module: `xfrac'
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\ChemModule{xfrac}{2015/07/22 use xfrac package with chemmacros}
+
+\RequirePackage{xfrac}
+
+% --------------------------------------------------------------------------
+
+% #1: type
+% #2: numerator
+% #3: denominator
+\cs_new_protected:Npn \chemmacros_frac:nnn #1#2#3
+  {
+    \IfInstanceExistTF {xfrac} {chemmacros-frac-\f@family-#1}
+      { \sfrac [chemmacros-frac-\f@family-#1] {#2} {#3} }
+      { \sfrac [chemmacros-frac-default-#1]{#2} {#3} }
+  }
+
+\NewDocumentCommand \chemfrac {O{text}mm}
+  { \chemmacros_frac:nnn {#1} {#2} {#3} }
+
+% --------------------------------------------------------------------------
+
+% default:
+\DeclareInstance {xfrac} {chemmacros-frac-cmr-superscript} {text}
+  {
+    numerator-top-sep   = -.1ex ,
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = cmr
+  }
+
+\DeclareInstance {xfrac} {chemmacros-frac-cmr-text} {text}
+  {
+    numerator-top-sep   = 0ex ,
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = cmr
+  }
+
+% computer modern (same as default):
+\DeclareInstance {xfrac} {chemmacros-frac-cmr-superscript} {text}
+  {
+    numerator-top-sep   = -.1ex ,
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = cmr
+  }
+
+\DeclareInstance {xfrac} {chemmacros-frac-cmr-text} {text}
+  {
+    numerator-top-sep   = 0ex ,
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = cmr
+  }
+
+% Linux Libertine T lining:
+\DeclareInstance {xfrac} {chemmacros-frac-LinuxLibertineT-TLF-text} {text}
+  {
+    numerator-top-sep   = 0ex ,
+    slash-left-kern     = 0em ,
+    slash-right-kern    = .05em ,
+    slash-symbol-font   = LinuxLibertineT-TLF
+  }
+
+\DeclareInstance {xfrac} {chemmacros-frac-LinuxLibertineT-TLF-superscript} {text}
+  {
+    scale-factor        = 1.2 ,
+    denominator-bot-sep = -.1ex ,
+    numerator-top-sep   = -.1ex ,
+    slash-left-kern     = .1em ,
+    slash-right-kern    = .1em ,
+    slash-symbol-font   = LinuxLibertineT-TLF
+  }
+
+% Linux Libertine T oldstyle:
+\DeclareInstance {xfrac} {chemmacros-frac-LinuxLibertineT-TOsF-text} {text}
+  {
+    denominator-bot-sep = .1ex ,
+    numerator-top-sep   = -.2ex ,
+    slash-left-kern     = 0em ,
+    slash-right-kern    = 0em ,
+    slash-symbol-font   = LinuxLibertineT-TOsF
+  }
+
+\DeclareInstance {xfrac} {chemmacros-frac-LinuxLibertineT-TOsF-superscript} {text}
+  {
+    scale-factor        = 1.2 ,
+    denominator-bot-sep = -.1ex ,
+    numerator-top-sep   = -.2ex ,
+    slash-left-kern     = 0em ,
+    slash-right-kern    = .1em ,
+    slash-symbol-font   = LinuxLibertineT-TOsF
+  }
+
+% lmodern:
+\DeclareInstance {xfrac} {chemmacros-frac-lmr-superscript} {text}
+  {
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = lmr
+  }
+
+\DeclareInstance {xfrac} {chemmacros-frac-lmr-text} {text}
+  {
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = lmr
+  }
+
+% --------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.sty b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.sty
index d6d1a07b195..27fcc7a93cd 100644
--- a/Master/texmf-dist/tex/latex/chemmacros/chemmacros.sty
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros.sty
@@ -1,7 +1,7 @@
 % --------------------------------------------------------------------------
 % the CHEMMACROS package
 %
-%   loads of little helpers for chemists
+%   comprehensive support for typesetting chemistry documents
 %
 % --------------------------------------------------------------------------
 % Clemens Niederberger
@@ -26,4089 +26,162 @@
 %
 % The Current Maintainer of this work is Clemens Niederberger.
 % --------------------------------------------------------------------------
-\RequirePackage{ expl3 , xparse , l3keys2e }
-\def\chemmacros@version{4.7}
-\def\chemmacros@date{2015/02/08}
-
-\ProvidesExplPackage
-  {chemmacros}
-  {\chemmacros@date}
-  {\chemmacros@version}
-  {loads of little helpers for chemists (CN)}
-
-% --------------------------------------------------------------------------
-% check expl3 version:
-\@ifpackagelater { expl3 } { 2013/12/14 }
-  { }
-  {
-    \PackageError { chemmacros } { Support~package~expl3~too~old }
-      {
-        You~need~to~update~your~installation~of~the~bundles~'l3kernel'~and~
-        'l3packages'.\MessageBreak
-        Loading~chemmacros~will~abort!
-      }
-    \tex_endinput:D
-  }
-
-% --------------------------------------------------------------------------
-% variants of kernel commands:
-\cs_generate_variant:Nn \prop_if_in:NnTF   { NV , Nx }
-\cs_generate_variant:Nn \prop_put:Nnn      { NV , NVV , NVx }
-\cs_generate_variant:Nn \prop_get:NnNTF    { NV }
-\cs_generate_variant:Nn \tl_set_rescan:Nnn { NnV }
-\cs_generate_variant:Nn \tl_if_eq:nnTF     { V }
-\cs_generate_variant:Nn \tl_const:cn       { cV }
-\cs_generate_variant:Nn \tl_to_lowercase:n { f }
-
-% --------------------------------------------------------------------------
-% load required packages
-% the technical ones:
-\RequirePackage { environ , scrlfile , etoolbox , translations }
-% related to other topics like mathematics or graphics:
-\RequirePackage { xfrac , siunitx , tikz, mathtools , bm }
-% other packages of this bundle -- ghsystem is not loaded here but at the end
-% of the preamble depending on a package option:
-\RequirePackage { chemformula , chemgreek }
-% TikZ libraries (the don't like expl3 syntax):
-\ExplSyntaxOff
-\usetikzlibrary{calc,arrows}
+\RequirePackage{expl3,xparse,l3keys2e}
 \ExplSyntaxOn
 
 % --------------------------------------------------------------------------
-% boolean variables for the package options
-\bool_new:N      \l__chemmacros_xspace_bool
-\bool_set_true:N \l__chemmacros_xspace_bool
-
-\bool_new:N      \l__chemmacros_circled_bool
-\bool_set_true:N \l__chemmacros_circled_bool
-\bool_new:N      \l__chemmacros_circled_formal_bool
-\bool_set_true:N \l__chemmacros_circled_formal_bool
-\bool_new:N      \l__chemmacros_circled_chem_bool
-\bool_set_true:N \l__chemmacros_circled_chem_bool
-
-\bool_new:N      \l__chemmacros_EZ_cool_bool
-\bool_new:N      \l__chemmacros_Nu_mathspec_bool
-\bool_new:N      \l__chemmacros_chemstyle_bool
-\bool_new:N      \l__chemmacros_hyperref_bool
-\bool_new:N      \l__chemmacros_varioref_bool
-\bool_new:N      \l__chemmacros_chemfig_bool
-\bool_new:N      \l__chemmacros_ghsystem_bool
-% \bool_set_true:N \l__chemmacros_ghsystem_bool
-
-\bool_new:N      \l__chemmacros_iupac_restricted_bool
-\bool_new:N      \l__chemmacros_iupac_strict_bool
-\bool_new:N      \l__chemmacros_in_document_bool
+% package information:
+\tl_const:Nn \c_chemmacros_date_tl {2015/09/11}
+\tl_const:Nn \c_chemmacros_version_major_number_tl {5}
+\tl_const:Nn \c_chemmacros_version_minor_number_tl {0}
+\tl_const:Nn \c_chemmacros_version_subrelease_tl   {}
+\tl_const:Nx \c_chemmacros_version_number_tl
+  {\c_chemmacros_version_major_number_tl.\c_chemmacros_version_minor_number_tl}
+\tl_const:Nx \c_chemmacros_version_tl
+  { \c_chemmacros_version_number_tl \c_chemmacros_version_subrelease_tl }
+\tl_const:Nn \c_chemmacros_info_tl
+  {comprehensive~ support~ for~ typesetting~ chemistry~ documents}
 
-\AtBeginDocument
-  {
-    \bool_set_true:N \l__chemmacros_in_document_bool
-    \@ifpackageloaded { chemstyle }
-      { \bool_set_true:N \l__chemmacros_chemstyle_bool }
-      { \bool_set_false:N \l__chemmacros_chemstyle_bool }
-    \@ifpackageloaded { varioref }
-      { \bool_set_true:N \l__chemmacros_varioref_bool }
-      { \bool_set_false:N \l__chemmacros_varioref_bool }
-    \@ifpackageloaded { hyperref }
-      { \bool_set_true:N \l__chemmacros_hyperref_bool }
-      { \bool_set_false:N \l__chemmacros_hyperref_bool }
-    \@ifpackageloaded { chemfig }
-      { \bool_set_true:N \l__chemmacros_chemfig_bool }
-      { \bool_set_false:N \l__chemmacros_chemfig_bool }
-  }
+\ProvidesExplPackage
+  {chemmacros}
+  {\c_chemmacros_date_tl}
+  {\c_chemmacros_version_tl}
+  {\c_chemmacros_info_tl \c_space_tl (CN)}
 
 % --------------------------------------------------------------------------
-% warning / error messages
-\msg_new:nnnn { chemmacros } { language-not-defined }
-  { The~ language~ `#1'~ is~ not~ defined~ by~ chemmacros. }
-  {
-    You~ chose~ the~ language~ `#1'~ which~ is~ not~ defined~ by~ chemmacros.~
-    `english'~ is~ used~ instead.~ If~ you~ just~ mistyped~ try~ again!~
-    Otherwise~ contact~ the~ author~ and~ he'll~ probably~ add~ your~ language.
-  }
-
-\msg_new:nnnn { chemmacros } { already-defined }
-  { The~ command~ #1~ is~ already~ defined. }
-  {
-    The~ command~ #1~ has~ already~ been~ otherwise.~ chemmacros~ also~ tries~
-    to~ define~ it~ and~ fails.~
-  }
-
-\msg_new:nnnn { chemmacros } { not-defined }
-  { The~ command~ #1~ is~ not~ defined,~ yet. }
-  {
-    The~ command~ #1~ is~ not~ defined,~ yet.~ chemmacros~ tries~ to~
-    redefine~ it~ and~ fails.~
-  }
-
-\msg_new:nnnn { chemmacros } { option-deprecated }
-  { The~ option~ `#1'~ is~ deprecated.~ I~ will~ ignore~ it. }
-  {
-    The~ package~ option~ `#1'~ is~ deprecated~ and~ not~ used~ by~
-    chemmacros~ any~ more.~ It~ will~ therefore~ simply~ be~ ignored.
-  }
-
-\msg_new:nnnn { chemmacros } { command-deprecated }
-  {
-    The~ command~ \token_to_str:N #1 \c_space_tl is~ deprecated.~ Use~
-    \token_to_str:N #2 \c_space_tl instead.
-  }
-  {
-    The~ command~ \token_to_str:N #1 \c_space_tl is~ deprecated.~ Use~
-    \token_to_str:N #2 \c_space_tl instead.
-  }
-
-\msg_new:nnnn { chemmacros } { command-dropped }
-  {
-    The~ command~ \token_to_str:N #1 \c_space_tl has~ been~ dropped.~ I'm~
-    sorry.
-  }
-  {
-    The~ command~ \token_to_str:N #1 \c_space_tl has~ been~ dropped.~ I'm~
-    sorry.
-  }
-
-\msg_new:nnnn { chemmacros } { new-particle }
-  {
-    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
-    defined.
-  }
-  {
-    You've~ tried~ to~ define~ a~ particle~ with~ \token_to_str:N
-    \NewChemParticle ,~ but~ the~ command~ sequence~ \token_to_str:N #1
-    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
-  }
-
-\msg_new:nnnn { chemmacros } { renew-particle }
-  { The~ particle~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
-  {
-    You've~ tried~ to~ renew~ the~ particle~ \token_to_str:N #1 ,~ but~ it~
-    doesn't~ exist.
-  }
-
-\msg_new:nnnn { chemmacros } { new-latin }
-  {
-    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
-    defined.
-  }
-  {
-    You've~ tried~ to~ define~ a~ latin~ phrase~ with~\token_to_str:N
-    \NewChemLatin ,~ but~ the~ command~ sequence~ \token_to_str:N #1
-    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
-  }
-
-\msg_new:nnnn { chemmacros } { renew-latin }
-  { The~ latin~ phrase \token_to_str:N #1 \c_space_tl is~ not~ defined. }
-  {
-    You've~ tried~ to~ renew~ the~ latin~ phrase~ \token_to_str:N #1 ,~ but~
-    it~ doesn't~ exist.
-  }
-
-\msg_new:nnnn { chemmacros } { new-nmr }
-  {
-    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
-    defined.
-  }
-  {
-    You've~ tried~ to~ define~ a~ NMR~ command~ with~\token_to_str:N
-    \NewChemParticle ,~ but~ the~ command~ sequence~ \token_to_str:N #1
-    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
-  }
-
-\msg_new:nnnn { chemmacros } { renew-nmr }
-  { The~ NMR~ command~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
+% messages:
+\msg_new:nnn {chemmacros} {too-low-compatibility}
   {
-    You've~ tried~ to~ renew~ the~ NMR~ command~ \token_to_str:N #1 ,~ but~
-    it~ doesn't~ exist.
+    Compatibility~ for~ versions~ below~ v4.7~ is~ not~ supported!~ You~
+    requested~ version~ v #1.~ Loading~ v4.7~ instead.
   }
 
-\msg_new:nnnn { chemmacros } { new-phase }
+\msg_new:nnn {chemmacros} {low-compatibility}
   {
-    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
-    defined.
-  }
-  {
-    You've~ tried~ to~ define~ a~ phase~ with~ \token_to_str:N
-    \NewChemPhase ,~ but~ the~ command~ sequence~ \token_to_str:N #1
-    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
-  }
-
-\msg_new:nnnn { chemmacros } { renew-phase }
-  { The~ phase~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
-  {
-    You've~ tried~ to~ renew~ the~ phase~ \token_to_str:N #1 ,~ but~ it~
-    doesn't~ exist.
-  }
-
-\msg_new:nnnn { chemmacros } { new-iupac }
-  {
-    The~ iupac~ naming~ command~ \token_to_str:N #1 \c_space_tl is~ already~
-    defined.
-  }
-  {
-    You've~ tried~ to~ define~ a~ iupac~ naming~ command~ with~
-    \token_to_str:N \NewChemIUPAC ,~ but~ the~ iupac~ command~
-    \token_to_str:N #1 \c_space_tl already~ exists.~ Choose~ another~ name~
-    or~ use~ \token_to_str:N \RenewChemIUPAC .
-  }
-
-\msg_new:nnnn { chemmacros } { renew-iupac }
-  {
-    The~ iupac~ naming~ command~ \token_to_str:N #1 \c_space_tl is~ not~
-    defined.
-  }
-  {
-    You've~ tried~ to~ renew~ the~ iupac~ command~ \token_to_str:N #1 ,~ but~
-    it~ doesn't~ exist.~ Use~ \token_to_str:N \NewChemIUPAC \c_space_tl
-    instead.
-  }
-
-\msg_new:nnnn { chemmacros } { let-iupac }
-  {
-    The~ iupac~ naming~ command~ \token_to_str:N #2 \c_space_tl is~ not~
-    defined.
-  }
-  {
-    You've~ tried~ to~ let~ the~ iupac~ command~ \token_to_str:N #1 ~ to~ the~
-    iupac~ command~ \token_to_str:N #2 ,~ but~ the~ latter~ doesn't~ exist.~
-    Use~ \token_to_str:N \NewChemIUPAC \c_space_tl instead~ or~declare~
-    \token_to_str:N #2 \c_space_tl first.
-  }
-
-\msg_new:nnnn { chemmacros } { ox }
-  { \token_to_str:N \ox \c_space_tl : ~ #1 ~ \msg_line_context: . }
-  { \token_to_str:N \ox \c_space_tl : ~ #1 ~ \msg_line_context: . }
-
-\msg_new:nnnn { chemmacros } { OX }
-  { \token_to_str:N \OX \c_space_tl : ~ #1 ~ \msg_line_context: . }
-  { \token_to_str:N \OX \c_space_tl : ~ #1 ~ \msg_line_context: . }
-
-\msg_new:nnnn { chemmacros } { redox }
-  { \token_to_str:N \redox \c_space_tl : ~ #1 ~ \msg_line_context: . }
-  { \token_to_str:N \redox \c_space_tl : ~ #1 ~ \msg_line_context: . }
-
-\msg_new:nnnn { chemmacros } { chemfig }
-  {
-    You~ need~ to~ load~ the~ `chemfig'~ package~ in~ order~ to~ make~
-    \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl work~
-    properly~ \msg_line_context: .
-  }
-  {
-    You~ need~ to~ load~ the~ `chemfig'~ package~ in~ order~ to~ make~
-    \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl work~
-    properly~ \msg_line_context: .
+    You~ requested~ compatibility~ mode~ v #1~ while~ the~ current~ version~
+    of~ chemmacros~ is~ v \c_chemmacros_version_number_tl .~ Not~ all~ features~
+    will~ be~ available!
   }
 
-\msg_new:nnnn { chemmacros } { new-state }
-  {
-    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
-    already~ exists.~ You~ need~ to~ use~ \token_to_str:N \RenewChemState
-    \c_space_tl to~ alter~ it~ \msg_line_context: .
-  }
-  {
-    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
-    already~ exists.~ You~ need~ to~ use~ \token_to_str:N \RenewChemState
-    \c_space_tl to~ alter~ it~ \msg_line_context: .
-  }
-
-\msg_new:nnnn { chemmacros } { renew-state }
-  {
-    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
-    isn't~ set~ up~ yet.~ You~ need~ to~ use~ \token_to_str:N
-    \NewChemState \c_space_tl to~ create~ it~ \msg_line_context: .
-  }
-  {
-    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
-    isn't~ set~ up~ yet.~ You~ need~ to~ use~ \token_to_str:N
-    \NewChemState \c_space_tl to~ create ~it~ \msg_line_context: .
-  }
-
-\msg_new:nnn { chemmacros } { state-syntax }
-  {
-    You're~ using~ a~ no~ longer~ recommended~ syntax~ to~ (re-)define~ a~
-    state~ variable~ \msg_line_context: .~ This~ syntax~ may~ deprecate~ and~
-    be~ removed~ in~ the~ future.
-  }
-
-% declare an option as deprecated:
-\cs_new_protected:Npn \chemmacros_option_deprecated:n #1
-  { \msg_warning:nnn { chemmacros } { option-deprecated } { #1 } }
-
-% define a deprecated command with hints to the corresponding new one:
-\cs_new_protected:Npn \chemmacros_define_deprecated:NN #1#2
-  {
-    \cs_set_protected:Npn #1
-      {
-        \msg_warning:nnxx { chemmacros } { command-deprecated }
-          { #1 } { #2 }
-        #2
-      }
-  }
-
-\NewDocumentCommand \DeclareChemDeprecated { mm }
-  { \chemmacros_define_deprecated:NN #1 #2 }
-
-% define a command as dropped!
-\cs_new_protected:Npn \chemmacros_define_dropped:N #1
-  {
-    \cs_set_protected:Npn #1
-      { \msg_error:nnn { chemmacros } { command-dropped } { #1 } }
-  }
-
-\NewDocumentCommand \DeclareChemDropped { m }
-  { \chemmacros_define_dropped:N #1 }
-
 % --------------------------------------------------------------------------
-% temporary variables
-\tl_new:N  \l__chemmacros_tmpa_tl
-\tl_new:N  \l__chemmacros_tmpb_tl
-\int_new:N \l__chemmacros_tmpa_int
-\box_new:N \l__chemmacros_tmpa_box
+% compatibility
+\fp_new:N \l__chemmacros_compatibility_version_fp
+\fp_set:Nn \l__chemmacros_compatibility_version_fp {\c_chemmacros_version_number_tl}
 
-% --------------------------------------------------------------------------
-% language settings:
-\bool_new:N      \l__chemmacros_language_auto_bool
-\bool_set_true:N \l__chemmacros_language_auto_bool
-% this token list will hold the chosen language for chemmacros; since the
-% language is either chosen automatically or by option it is only available at
-% begin document
-\tl_new:N        \l_chemmacros_language_tl
-\tl_set:Nn       \l_chemmacros_language_tl { english }
-\tl_new:N        \l__chemmacros_current_language_tl
-
-% translate the key #1
-\cs_new:Npn \chemmacros_translate:n #1
+\keys_define:nn {chemmacros/compatibility}
   {
-    \bool_if:NTF \l__chemmacros_language_auto_bool
-      { \GetTranslation{#1} }
-      { \GetTranslationFor{\l_chemmacros_language_tl}{#1} }
+    compatibility .fp_set:N = \l__chemmacros_compatibility_version_fp ,
+    unknown       .code:n   =
+      \PassOptionsToPackage{\CurrentOption}{chemmacros4}
+      \PassOptionsToPackage{\CurrentOption}{chemmacros5}
   }
 
-\AtBeginDocument{
-  \bool_if:NTF \l__chemmacros_language_auto_bool
-    {
-      \tl_set:Nx \l_chemmacros_language_tl
-        { \@trnslt@language{\@trnslt@current@language} }
-    }
-    {
-      \tl_set_eq:NN
-        \l_chemmacros_language_tl
-        \l__chemmacros_current_language_tl
-    }
-}
+\ProcessKeysPackageOptions {chemmacros/compatibility}
 
 % --------------------------------------------------------------------------
-% package options
-%   circled     => circle charges
-%   detect-bold => behaviour when font series bold
-%   EZ          => cool or chemmacros version of \E
-%   german      => change pKA => pKS etc
-%   iupac       => behaviour of nomenclature commands
-%   ngerman     => an alias :)
-%   ghsystem    => load ghsystem or don't
-%   method      => use `chemformula' or `mhchem'
-%   strict      => errors or warnings
-%   synchronize => let particles et.al. adapt chemformula's font selection
-%   ugreek      => behaviour of \chemDelta, \chemalpha, ...
-%   version=1   => compatibility for documents set with v1.*
-%   xspace      => add an \xspace after a whole bunch of macros
-
-% this boolean has to be public since the other packages of the bundle may
-% want to know its value
-
-\bool_new:N \l__chemmacros_detect_bold_bool
-\bool_set_true:N \l__chemmacros_detect_bold_bool
-
-\bool_new:N \l__chemmacros_option_greek_set_bool
-\bool_new:N \l__chemmacros_use_upgreek_bool
-\bool_new:N \l__chemmacros_use_textgreek_bool
-\bool_new:N \l__chemmacros_use_kpfonts_bool
-\bool_new:N \l__chemmacros_use_newtx_bool
-
-\cs_new:Npn \chemmacros_inner_font: {}
-
-\keys_define:nn { chemmacros / option }
+% compare version numbers
+% #1: number
+% #2: relation
+% #3: number
+% #4: true
+% #5: false
+\prg_new_conditional:Npnn \chemmacros_if_version:nnn #1#2#3 {p,T,F,TF}
   {
-    bpchem             .code:n = \chemmacros_option_deprecated:n { bpchem } ,
-    circletype         .choice: ,
-    circletype / math  .code:n  =
-      { \bool_set_false:N \l__chemmacros_circled_chem_bool } ,
-    circletype / chem  .code:n  =
-      { \bool_set_true:N \l__chemmacros_circled_chem_bool } ,
-    circletype         .default:n = chem ,
-    circled            .choice: ,
-    circled / none     .code:n =
-      {
-        \bool_set_false:N \l__chemmacros_circled_bool
-        \bool_set_false:N \l__chemmacros_circled_formal_bool
-      } ,
-    circled / formal   .code:n =
+    \fp_compare:nTF { floor(#1) = floor(#3) }
       {
-        \bool_set_true:N \l__chemmacros_circled_bool
-        \bool_set_true:N \l__chemmacros_circled_formal_bool
-      } ,
-    circled / all      .code:n =
-      {
-        \bool_set_true:N \l__chemmacros_circled_bool
-        \bool_set_false:N \l__chemmacros_circled_formal_bool
-      } ,
-    circled            .default:n  = all ,
-    detect-bold        .code:n = \chemmacros_option_deprecated:n { detect-bold } ,
-    EZ                 .code:n = \chemmacros_option_deprecated:n { EZ } ,
-    german             .code:n     =
-      \tl_set:Nn \l__chemmacros_current_language_tl { german } ,
-    ngerman            .code:n     =
-      \tl_set:Nn \l__chemmacros_current_language_tl { ngerman } ,
-    ghsystem           .bool_set:N = \l__chemmacros_ghsystem_bool ,
-    ghsystem           .default:n  = true ,
-    iupac              .choice: ,
-    iupac / restricted .code:n     =
-      \bool_set_true:N \l__chemmacros_iupac_restricted_bool
-      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
-    iupac / auto       .code:n     =
-      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
-      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
-    iupac / strict     .code:n     =
-      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
-      \bool_set_true:N \l__chemmacros_iupac_strict_bool ,
-    language           .code:n     =
-      \tl_if_eq:nnTF { #1 } { auto }
-        { \bool_set_true:N \l__chemmacros_language_auto_bool }
-        {
-          \bool_set_false:N \l__chemmacros_language_auto_bool
-          \tl_set:Nn \l__chemmacros_current_language_tl { #1 }
-        } ,
-    method             .choice: ,
-    method / chemformula   .code:n     =
-      \chemmacros_option_deprecated:n { method } ,
-    method / mhchem    .code:n     =
-      \chemmacros_option_deprecated:n { method } ,
-    Nu                 .choice: ,
-    Nu / mathspec      .code:n     =
-     \bool_set_true:N \l__chemmacros_Nu_mathspec_bool ,
-    Nu / chemmacros    .code:n     =
-     \bool_set_false:N \l__chemmacros_Nu_mathspec_bool ,
-    strict             .code:n     =
-      \chemmacros_option_deprecated:n { strict } ,
-    synchronize        .choice: ,
-    synchronize / true .code:n     =
-      \cs_set_eq:NN \chemmacros_inner_font: \chemformula_font_inner: ,
-    synchronize / false .code:n = \cs_set:Nn \chemmacros_inner_font: {} ,
-    synchronize        .default:n  = true ,
-    greek              .choice: ,
-    greek / upgreek    .code:n     =
-      \chemgreek_activate_mapping:n { upgreek }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / textgreek   .code:n    =
-      \chemgreek_activate_mapping:n { textgreek }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / kpfonts    .code:n     =
-      \chemgreek_activate_mapping:n { kpfonts }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / newtx      .code:n     =
-      \chemgreek_activate_mapping:n { newtx }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / mathdesign .code:n     =
-      \chemgreek_activate_mapping:n { mathdesign }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / fourier    .code:n     =
-      \chemgreek_activate_mapping:n { fourier }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / textalpha  .code:n     =
-      \chemgreek_activate_mapping:n { textalpha }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / math       .code:n     =
-      \chemgreek_activate_mapping:n { default }
-      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
-    greek / auto       .code:n     =
-      \bool_set_false:N \l__chemmacros_option_greek_set_bool ,
-    greek              .default:n  = auto ,
-    upgreek            .code:n = \chemmacros_option_deprecated:n { upgreek } ,
-    version            .code:n = \chemmacros_option_deprecated:n { version } ,
-    cmversion          .code:n = \chemmacros_option_deprecated:n { cmversion } ,
-    cmversion          .choice: ,
-    xspace             .bool_set:N = \l__chemmacros_xspace_bool ,
-    xspace             .default:n  = true
-  }
-
-
-
-\ProcessKeysOptions { chemmacros / option }
-
-% --------------------------------------------------------------------------
-% set up a few things:
-% - is `ghsystem' requested?
-% - do we need `xspace'?
-% - what about the greek letters?
-
-\seq_new:N  \l__chemmacros_greek_packages_seq
-\prop_new:N \l__chemmacros_greek_mapping_prop
-
-\cs_new_protected:Npn \chemmacros_add_greek_package_mapping:nn #1#2
-  {
-    \seq_put_right:Nn \l__chemmacros_greek_packages_seq {#1}
-    \prop_put:Nnn \l__chemmacros_greek_mapping_prop {#1} {#2}
-  }
-
-\cs_generate_variant:Nn \chemgreek_activate_mapping:n { V }
-
-\cs_new_protected:Npn \__chemmacros_select_greek_mapping:n #1
-  {
-    \bool_if:NF \l__chemmacros_option_greek_set_bool
+        \fp_compare:nTF
+          { (\chemmacros_get_minor:f {#1}) #2 (\chemmacros_get_minor:f {#3}) }
+          { \prg_return_true: }
+          { \prg_return_false: }
+      }
       {
-        \@ifpackageloaded { #1 }
-          {
-            \prop_get:NnN
-              \l__chemmacros_greek_mapping_prop
-              { #1 }
-              \l__chemmacros_tmpa_tl
-            \chemgreek_activate_mapping:V \l__chemmacros_tmpa_tl
-            \bool_set_true:N \l__chemmacros_option_greek_set_bool
-            \seq_map_break:
-          }
-          { }
+        \fp_compare:nTF { (#1) #2 (#3) }
+          { \prg_return_true: }
+          { \prg_return_false: }
       }
   }
 
-\chemmacros_add_greek_package_mapping:nn {upgreek}    {upgreek}
-\chemmacros_add_greek_package_mapping:nn {textgreek}  {textgreek}
-\chemmacros_add_greek_package_mapping:nn {mathdesign} {mathdesign}
-\chemmacros_add_greek_package_mapping:nn {kpfonts}    {kpfonts}
-\chemmacros_add_greek_package_mapping:nn {newtxmath}  {newtx}
-\chemmacros_add_greek_package_mapping:nn {fourier}    {fourier}
-\chemmacros_add_greek_package_mapping:nn {textalpha}  {textalpha}
-
-\AtEndPreamble
-  {
-    \bool_if:NT \l__chemmacros_ghsystem_bool
-      { \RequirePackage { ghsystem } }
-    \bool_if:NT \l__chemmacros_xspace_bool
-      { \RequirePackage { xspace } }
-    \seq_map_function:NN
-      \l__chemmacros_greek_packages_seq
-      \__chemmacros_select_greek_mapping:n
-  }
-
-\cs_new_protected:Npn \chemmacros_xspace:
-  { \bool_if:NT \l__chemmacros_xspace_bool { \xspace } }
+\cs_new:Npn \__chemmacros_get_minor:w #1.#2.#3 \q_stop
+  { \tl_if_blank:nTF {#2} {0} {#2} }
+\cs_new:Npn \chemmacros_get_minor:n #1
+  { \__chemmacros_get_minor:w #1.. \q_stop }
+\cs_generate_variant:Nn \chemmacros_get_minor:n {f}
 
-% --------------------------------------------------------------------------
-% TikZ drawings - helper macros
-\cs_new_protected:Npn \chemmacros_tikz_picture:nn #1#2
-  { \tikzpicture[#1] #2 \endtikzpicture }
-\cs_generate_variant:Nn \chemmacros_tikz_picture:nn { fn,xn }
-
-\cs_new_protected:Npn \chemmacros_tikz_draw:n #1
-  { \draw[#1] }
-\cs_generate_variant:Nn \chemmacros_tikz_draw:n { f,x }
-
-\cs_new_protected:Npn \chemmacros_tikz_node:n #1
-  { \node[#1] }
-\cs_generate_variant:Nn \chemmacros_tikz_node:n { f,x }
-
-\cs_new_protected:Npn \chemmacros_tikz_shade:n #1
-  { \shade[#1] }
-\cs_generate_variant:Nn \chemmacros_tikz_shade:n { f,x }
-
-\cs_new_protected:Npn \chemmacros_tikz_shadedraw:n #1
-  { \shadedraw[#1] }
-\cs_generate_variant:Nn \chemmacros_tikz_shadedraw:n { f,x }
-
-\cs_new_protected:Npn \chemmacros_tikz_node_in_draw:n #1
-  { node[#1] }
-\cs_generate_variant:Nn \chemmacros_tikz_node_in_draw:n { f,x }
-
-% --------------------------------------------------------------------------
-% a few general functions:
-\cs_new_eq:NN \chemmacros_leave_vmode:   \chemformula_leave_vmode:
-\cs_new_eq:NN \chemmacros_ignore_spaces: \tex_ignorespaces:D
-\cs_new_eq:NN \chemmacros_nobreak:       \chemformula_nobreak:
-\cs_new_eq:NN \chemmacros_allow_break:   \chemformula_allow_break:
-\cs_new_eq:NN \chemmacros_skip_nobreak:N \chemformula_skip_nobreak:N
-\cs_new:Npn   \chemmacros_remove_backslash:N #1
-  { \exp_after:wN \use_none:n \token_to_str:N #1 }
-
-\prg_new_protected_conditional:Npnn \chemmacros_if_is_cs:n #1 { T,F,TF }
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl { \token_if_cs:NTF #1 { } { x } }
-    \tl_if_blank:VTF \l__chemmacros_tmpa_tl
-      { \prg_return_true: }
-      { \prg_return_false: }
-  }
-
-% detection and handling of bold face:
-\prg_new_protected_conditional:Npnn \chemmacros_if_bold: { T,F,TF }
+% check compatibility
+% #1: relation
+% #2: number
+% #3: true
+% #4: false
+\prg_new_conditional:Npnn \chemmacros_if_compatiblity:nn #1#2 {p,T,F,TF}
   {
-    \seq_if_in:NVTF \l__chemmacros_if_bf_seq \f@series
+    \chemmacros_if_version:nnnTF
+      { \fp_to_decimal:N \l__chemmacros_compatibility_version_fp }
+      {#1}
+      {#2}
       { \prg_return_true: }
       { \prg_return_false: }
   }
+\cs_generate_variant:Nn \chemmacros_if_compatiblity:nnT {nV}
 
-\seq_new:N  \l__chemmacros_if_bf_seq
-
-\seq_set_split:Nnn \l__chemmacros_if_bf_seq { , }
-  {
-    b , bc , bm , bx , bux ,
-    eb , ebc , ebx , mb ,
-    sb , sbc , sbx ,
-    ub , ubc , ubx
-  }
-
-\cs_new_protected:Npn \chemmacros_bm:n #1
-  {
-    \bool_if:NTF \l__chemmacros_detect_bold_bool
-      { \bm { #1 } }
-      { #1 }
-  }
-
-\cs_new_protected:Npn \chemmacros_bf:n #1
-  {
-    \bool_if:NTF \l__chemmacros_detect_bold_bool
-      { { \normalfont \bfseries #1 } }
-      { { \normalfont #1 } }
-  }
-
-\cs_new_protected:Npn \chemmacros_detect_bold:n #1
-  {
-    \chemmacros_if_bold:TF
-      {
-        \mode_if_math:TF
-          { \chemmacros_bm:n { #1 } }
-          { \chemmacros_bf:n { #1 } }
-      }
-      { #1 }
-  }
-
-% ---------------------------------------------------------------------------
-% transition state symbol
-\cs_new_protected:Npn \__chemmacros_transition_state:
-  {
-    \text
-      {
-        \skip_horizontal:n { .1ex }
-        \hbox_overlap_right:n
-          { \rule { .6ex } { 0pt } \rule { .05ex } { 1.3ex } }
-        \hbox_overlap_right:n { \rule [ .4ex ] { 1.3ex } { .05ex } }
-        \rule [ .85ex ] { 1.3ex } { .05ex }
-        \skip_horizontal:n { .1ex }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_transition_state:
-  {
-    \ensuremath
-      {
-        \mathchoice
-          { \displaystyle }
-          { \textstyle }
-          { \scriptstyle }
-          { \scriptscriptstyle }
-        \__chemmacros_transition_state:
-      }
-  }
-
-% \DeclareDocumentCommand?
-\cs_new_eq:NN \transitionstatesymbol \chemmacros_transition_state:
-
-% --------------------------------------------------------------------------
-% let's make use of `chemformula' inside some of `chemmacros' commands:
-\cs_new_protected:Nn \chemmacros_atom:n
-  {
-    \mode_if_math:TF
-      { \text { \chemmacros_inner_font: #1 } }
-      { \group_begin: \chemmacros_inner_font: #1 \group_end: }
-  }
-\cs_generate_variant:Nn \chemmacros_atom:n { V }
-
-\cs_new_protected:Npn \chemmacros_text:n #1
-  { \mode_if_math:TF { \text { #1 } } { #1 } }
-
-\tl_new:N \l__chemmacros_chemformula_tl
-
-\cs_new_protected:Npn \chemmacros_chemformula:n #1
-  {
-    \group_begin:
-      \cs_set_eq:NN \chemformula_font_inner: \chemmacros_inner_font:
-      \chemformula_chcpd:nn {} { #1 }
-    \group_end:
-  }
-\cs_generate_variant:Nn \chemmacros_chemformula:n { x,V }
-
-% --------------------------------------------------------------------------
-% particles, charges
-\NewDocumentCommand \NewChemParticle { mm }
-  {
-    \cs_if_free:NTF #1
-      { \chemmacros_define_particle:Nn #1 { #2 } }
-      { \msg_error:nnn { chemmacros } { new-particle } { #1 } }
-  }
-
-\NewDocumentCommand \RenewChemParticle { mm }
-  {
-    \cs_if_free:NTF #1
-      { \msg_error:nnn { chemmacros } { renew-particle } { #1 } }
-      { \chemmacros_define_particle:Nn #1 { #2 } }
-  }
-
-\NewDocumentCommand \DeclareChemParticle { mm }
-  { \chemmacros_define_particle:Nn #1 { #2 } }
-
-\cs_new_protected:Nn \chemmacros_define_particle:Nn
-  {
-    \cs_set_protected:Npn #1
-      {
-        \chemformula_chcpd:nn {} { #2 }
-        \chemmacros_xspace:
-      }
-  }
-
-\NewChemParticle \el  { e- }
-\NewChemParticle \prt { p+ }
-\NewChemParticle \ntr { n^0 }
-
-% --------------------------------------------------------------------------
-% charges
-% circled charge signs: they are defined in the `chemformula' module:
-% use directly:
-
-\cs_new_protected:Npn \fplus  { { \chemformula_fplus:  } }
-\cs_new_protected:Npn \fminus { { \chemformula_fminus: } }
-
-% change output depending on circled-option
-\cs_new_eq:NN \chemmacros_plus: \chemformula_plus:
-\cs_new_eq:NN \chemmacros_minus: \chemformula_minus:
-
-\cs_new_protected:Npn \chemmacros_formal_plus:
-  {
-    \group_begin:
-      \bool_set_true:N \l__chemformula_formal_charges_bool
-      \chemformula_plus:
-    \group_end:
-  }
-
-\cs_new_protected:Npn \chemmacros_formal_minus:
-  {
-    \group_begin:
-      \bool_set_true:N \l__chemformula_formal_charges_bool
-      \chemformula_minus:
-    \group_end:
-  }
-
-\cs_new_protected:Npn \chemmacros_charge:n #1
-  {
-    \chemformula_superscript:n
-      { \chemmacros_detect_bold:n { #1 } }
-  }
-
-\keys_define:nn { chemmacros / charges }
-  { append .code:n = \chemmacros_option_deprecated:n { append } }
-
-\NewDocumentCommand \mch { o }
-  {
-    \IfNoValueTF { #1 }
-      { \chemmacros_charge:n { \chemmacros_minus: } }
-      { \chemmacros_charge:n { #1 \chemmacros_minus: } }
-  }
-
-\NewDocumentCommand \pch { o }
-  {
-    \IfNoValueTF { #1 }
-      { \chemmacros_charge:n { \chemmacros_plus: } }
-      { \chemmacros_charge:n { #1 \chemmacros_plus: } }
-  }
-
-\NewDocumentCommand \fmch { o }
-  {
-    \IfNoValueTF { #1 }
-      { \chemmacros_charge:n { \chemmacros_formal_minus: } }
-      { \chemmacros_charge:n { #1 \chemmacros_formal_minus: } }
-  }
-
-\NewDocumentCommand \fpch { o }
-  {
-    \IfNoValueTF { #1 }
-      { \chemmacros_charge:n { \chemmacros_formal_plus: } }
-      { \chemmacros_charge:n { #1 \chemmacros_formal_plus: } }
-  }
-
-\tl_new:N  \l__chemmacros_partial_charge_format_tl
-\tl_set:Nn \l__chemmacros_partial_charge_format_tl { \tiny }
-
-\cs_new_protected:Npn \delm
-  {
-    \mbox {
-      \l__chemmacros_partial_charge_format_tl
-      \c_math_toggle_token \delta \chemmacros_minus: \c_math_toggle_token
-    }
-    \chemmacros_xspace:
-  }
-\cs_new_protected:Npn \delp
-  {
-    \mbox {
-      \l__chemmacros_partial_charge_format_tl
-      \c_math_toggle_token \delta \chemmacros_plus: \c_math_toggle_token
-    }
-    \chemmacros_xspace:
-  }
-\cs_new_protected:Npn \fdelm
-  {
-    \mbox {
-      \l__chemmacros_partial_charge_format_tl
-      \c_math_toggle_token \delta \chemmacros_formal_minus: \c_math_toggle_token
-    }
-    \chemmacros_xspace:
-  }
-\cs_new_protected:Npn \fdelp
-  {
-    \mbox {
-      \l__chemmacros_partial_charge_format_tl
-      \c_math_toggle_token \delta \chemmacros_formal_plus: \c_math_toggle_token
-    }
-    \chemmacros_xspace:
-  }
-
-\cs_new_protected:Npn \scrm
-  { \ensuremath { \scriptstyle \chemmacros_minus: } }
-\cs_new_protected:Npn \scrp
-  { \ensuremath { \scriptstyle \chemmacros_plus: } }
-\cs_new_protected:Npn \fscrm
-  { \ensuremath { \scriptstyle \chemmacros_formal_minus: } }
-\cs_new_protected:Npn \fscrp
-  { \ensuremath { \scriptstyle \chemmacros_formal_plus: } }
-\cs_new_protected:Npn \fsscrm
-  { \ensuremath { \scriptscriptstyle \chemmacros_formal_minus: } }
-\cs_new_protected:Npn \fsscrp
-  { \ensuremath { \scriptscriptstyle \chemmacros_formal_plus: } }
-
-\keys_define:nn { chemmacros / charges }
-  {
-    partial-format .tl_set:N = \l__chemmacros_partial_charge_format_tl
-  }
-
-% --------------------------------------------------------------------------
-% ions, molecules
-% proton, hydroxide, hydronium/oxonium, water, nucleophile, electrophile
-\NewChemParticle \Hpl { H+ }
-\NewChemParticle \Hyd { OH- }
-\NewChemParticle \HtO { H3O+ }
-\NewChemParticle \El  { E+ }
-\NewChemParticle \water { H2O }
-
-\NewDocumentCommand \chemmacros_Nu:w { o }
-  {
-    \IfNoValueF { #1 } { \keys_set:nn { chemmacros / particle } { #1 } }
-    \bool_if:NTF \l__chemmacros_particle_elpair_bool
-      { \chemmacros_elpair:n { Nu } \mch }
-      { \chemmacros_chemformula:n { Nu- } }
-    \chemmacros_xspace:
-  }
-
-\AtBeginDocument
-  {
-    \bool_if:NTF \l__chemmacros_Nu_mathspec_bool
-      { \cs_set_eq:NN \Nuc \chemmacros_Nu:w }
-      { \cs_set_eq:NN \Nu \chemmacros_Nu:w }
-  }
-
-\cs_new_protected:Npn \chemmacros_ba:
-  {
-    \bool_if:NTF \l__chemmacros_particle_elpair_bool
-      { \chemmacros_elpair:n { ba } \mch }
-      { \chemmacros_chemformula:n { ba- } }
-    \chemmacros_xspace:
-  }
-
-\NewDocumentCommand \ba { o }
-  {
-    \group_begin:
-      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / particle } { #1 } }
-      \chemmacros_ba:
-    \group_end:
-  }
-
-\cs_new_protected:Npn \chemmacros_elpair:n #1
-  {
-    \bool_if:NTF \l__chemmacros_chemfig_bool
-      {
-        \bool_if:NTF \l__chemmacros_elpair_dots_bool
-          { \chlewis { 0: } { #1 } }
-          { \chlewis { 0| } { #1 } }
-%          { { \chemmacros_inner_font: #1 \chlewis { 0=| } { \vphantom { #1 } } } }
-      }
-      {
-        \msg_error:nnn { chemmacros } { chemfig } { #1 }
-        \chemmacros_atom:n { #1 }
-      }
-  }
+% user checks:
+\NewDocumentCommand \IfChemCompatibilityTF {mm+m+m}
+  { \chemmacros_if_compatiblity:nnTF {#1} {#2} {#3} {#4} }
 
-\bool_new:N \l__chemmacros_particle_elpair_bool
-\bool_new:N \l__chemmacros_elpair_dots_bool
+\NewDocumentCommand \IfChemCompatibilityT {mm+m}
+  { \chemmacros_if_compatiblity:nnT {#1} {#2} {#3} }
 
-\keys_define:nn { chemmacros / particle }
-  {
-    elpair         .choice: ,
-    elpair / false .code:n    =
-      { \bool_set_false:N \l__chemmacros_particle_elpair_bool } ,
-    elpair / dots  .code:n    =
-      {
-        \bool_set_true:N \l__chemmacros_particle_elpair_bool
-        \bool_set_true:N \l__chemmacros_elpair_dots_bool
-      } ,
-    elpair / dash  .code:n    =
-      {
-        \bool_set_true:N \l__chemmacros_particle_elpair_bool
-        \bool_set_false:N \l__chemmacros_elpair_dots_bool
-      } ,
-    elpair         .default:n = dots
-  }
+\NewDocumentCommand \IfChemCompatibilityF {mm+m}
+  { \chemmacros_if_compatiblity:nnF {#1} {#2} {#3} }
 
 % --------------------------------------------------------------------------
-% IUPAC
-\prop_new:N \l__chemmacros_iupac_prop
-
-\cs_new_protected:Npn \chemmacros_new_iupac:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
-      { \msg_error:nnn { chemmacros } { new-iupac } { #1 } }
-      {
-        \prop_put:NVn \l__chemmacros_iupac_prop
-          \l__chemmacros_tmpa_tl
-          { #2 }
-      }
-    \chemmacros_make_iupac:
-  }
-
-\cs_new_protected:Npn \chemmacros_define_iupac:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \prop_put:NVn \l__chemmacros_iupac_prop
-      \l__chemmacros_tmpa_tl
-      { #2 }
-    \chemmacros_make_iupac:
-  }
-
-\cs_new_protected:Npn \chemmacros_renew_iupac:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
-      {
-        \prop_put:NVn \l__chemmacros_iupac_prop
-          \l__chemmacros_tmpa_tl
-          { #2 }
-      }
-      { \msg_error:nnn { chemmacros } { renew-iupac } { #1 } }
-    \chemmacros_make_iupac:
-  }
-
-\cs_new_protected:Npn \chemmacros_let_iupac:NN #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \tl_set:Nx \l__chemmacros_tmpb_tl
-      { \chemmacros_remove_backslash:N #2 }
-    \prop_get:NVNTF \l__chemmacros_iupac_prop
-      \l__chemmacros_tmpb_tl
-      \l__chemmacros_tmpc_tl
-      {
-        \prop_put:NVV \l__chemmacros_iupac_prop
-          \l__chemmacros_tmpa_tl
-          \l__chemmacros_tmpc_tl
-      }
-      { \msg_error:nnnn { chemmacros } { let-iupac } { #1 } { #2 } }
-    \chemmacros_make_iupac:
-  }
-
-\cs_new_protected:Npn \chemmacros_define_deprecated_iupac:NN #1#2
-  {
-    \chemmacros_define_iupac:Nn #1
-      {
-        \msg_warning:nnnn { chemmacros } { command-deprecated }
-          { #1 } { #2 }
-        #2
-      }
-  }
-
-
-\cs_new_protected:Npn \chemmacros_make_iupac:
-  {
-    \bool_if:NT \l__chemmacros_in_document_bool
-      {
-        \bool_if:NTF \l__chemmacros_inside_iupac_bool
-          {
-            \prop_map_inline:Nn \l__chemmacros_iupac_prop
-              { \cs_set_protected:cpn { ##1 } { ##2 } }
-          }
-          {
-            \bool_if:NF \l__chemmacros_iupac_restricted_bool
-              {
-                \bool_if:NTF \l__chemmacros_iupac_strict_bool
-                  {
-                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
-                      { \cs_set_protected:cpn { ##1 } { ##2 } }
-                  }
-                  {
-                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
-                      {
-                        \cs_if_exist:cF { ##1 }
-                          { \cs_set_protected:cpn { ##1 } { ##2 } }
-                      }
-                  }
-              }
-          }
-      }    
-  }
-
-\AtBeginDocument { \chemmacros_make_iupac: }
-
-\NewDocumentCommand \DeclareChemIUPAC { mm }
-  { \chemmacros_define_iupac:Nn #1 { #2 } }
-
-\NewDocumentCommand \NewChemIUPAC { mm }
-  { \chemmacros_new_iupac:Nn #1 { #2 } }
-
-\NewDocumentCommand \RenewChemIUPAC { mm }
-  { \chemmacros_renew_iupac:Nn #1 { #2 } }
-
-\NewDocumentCommand \LetChemIUPAC { mm }
-  { \chemmacros_let_iupac:NN #1 #2 }
-
-\NewDocumentCommand \DeprecateChemIUPAC { mm }
-  { \chemmacros_define_deprecated_iupac:NN #1 #2 }
-
-% stereo descriptors and other nomenclature commands
-% Cahn-Ingold-Prelog
-\dim_new:N  \l__chemmacros_cip_kern_dim
-\dim_set:Nn \l__chemmacros_cip_kern_dim { .075em }
-
-\keys_define:nn { chemmacros / iupac }
-  { cip-kern .dim_set:N = \l__chemmacros_cip_kern_dim }
-
-\NewDocumentCommand \cip { m }
-  { \chemmacros_cip:n { #1 } }
-
-\cs_new_protected:Npn \chemmacros_cip:n #1
-  { ( \textit{#1} \tex_kern:D \l__chemmacros_cip_kern_dim ) }
-
-\DeprecateChemIUPAC \Rcip \rectus
-\DeprecateChemIUPAC \Scip \sinister
-
-\NewChemIUPAC \rectus   { \cip { R } }
-\NewChemIUPAC \sinister { \cip { S } }
-
-\LetChemIUPAC \R \rectus
-\LetChemIUPAC \S \sinister
-
-% TikZ needs : to be other
-\ExplSyntaxOff
-\protected\def\chemmacros@sconf#1%
-  {%
-    \begingroup
-    \tikz[baseline,text height=1.5ex,text depth=.25ex]
-      {
-        \node[anchor=base] (chemmacros@@Sconf) {#1} ;
-        \draw[->,thick,rotate=90]
-          ($(chemmacros@@Sconf.center)+(20:.8em)$) arc (20:340:.8em);
-      }%
-    \endgroup
-  }
-
-\protected\def\chemmacros@rconf#1%
-  {%
-    \begingroup
-    \tikz[baseline,text height=1.5ex,text depth=.25ex]
-      {
-        \node[anchor=base] (chemmacros@@Rconf) {#1} ;
-        \draw[<-,thick,rotate=90]
-          ($(chemmacros@@Rconf.center)+(20:.8em)$) arc (20:340:.8em) ;
-      }%
-    \endgroup
-  }
-\ExplSyntaxOn
-
-\NewDocumentCommand \Sconf { O{S} } { \chemmacros@sconf { #1 } }
-\NewDocumentCommand \Rconf { O{R} } { \chemmacros@rconf { #1 } }
-
-% E(ntgegen)/Z(usammen)
-\NewChemIUPAC \entgegen { \cip { E } }
-\NewChemIUPAC \zusammen { \cip { Z } }
-
-\LetChemIUPAC \E \entgegen
-\LetChemIUPAC \Z \zusammen
-
-% cis/trans
-\NewChemIUPAC \cis   { \textit { cis } }
-\NewChemIUPAC \trans { \textit { trans } }
-
-% fac/mer
-\NewChemIUPAC \fac { \textit { fac } }
-\NewChemIUPAC \mer { \textit { mer } }
-
-% tert
-\NewChemIUPAC \tert  { \textit { tert } }
-
-% Fischer
-\NewChemIUPAC \dexter { \textsc { d } }
-\NewChemIUPAC \laevus { \textsc { l } }
-
-\LetChemIUPAC \D \dexter
-\LetChemIUPAC \L \laevus
-
-% ortho/meta/para
-\NewChemIUPAC \ortho { \textit { o } }
-\NewChemIUPAC \meta  { \textit { m } }
-\NewChemIUPAC \para  { \textit { p } }
-
-% syn/anti
-\NewChemIUPAC \syn  { \textit { syn } }
-\NewChemIUPAC \anti { \textit { anti } }
-
-% coordination chemistry
-\bool_new:N \l__chemmacros_bridge_super_bool
-
-\keys_define:nn { chemmacros / iupac }
-  {
-    bridge-number         .choice: ,
-    bridge-number / sub   .code:n     =
-      \bool_set_false:N \l__chemmacros_bridge_super_bool ,
-    bridge-number / super .code:n     =
-      \bool_set_true:N \l__chemmacros_bridge_super_bool ,
-    coord-use-hyphen      .bool_set:N = \l__chemmacros_coord_use_hyphen_bool ,
-    coord-use-hyphen      .default:n  = true
-  }
-
-\cs_new_protected:Npn \chemformula_hapto:n #1
-  {
-    \chemeta \chemformula_superscript:n { #1 }
-    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
-      { \chemmacros_break_point_hyphen: }
-  }
-
-\cs_new_protected:Npn \chemformula_dento:n #1
-  {
-    \chemkappa \chemformula_superscript:n { #1 }
-    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
-      { \chemmacros_break_point_hyphen: }
-  }
-
-\cs_new_protected:Npn \chemformula_bridge:n #1
-  {
-    \chemmu
-    \tl_if_blank:nF { #1 }
-      {
-        \bool_if:NTF \l__chemmacros_bridge_super_bool
-          { \chemformula_superscript:n { #1 } }
-          { \chemformula_subscript:n { #1 } }
-      }
-    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
-      { \chemmacros_break_point_hyphen: }
-  }
-
-\NewChemIUPAC \hapto  { \chemformula_hapto:n }
-\NewChemIUPAC \dento  { \chemformula_dento:n }
-\NewChemIUPAC \bridge { \chemformula_bridge:n }
-
-% attachments to heteroatoms / added hydrogen
-\NewChemIUPAC \hydrogen   { \textit { H } }
-\NewChemIUPAC \oxygen     { \textit { O } }
-\NewChemIUPAC \nitrogen   { \textit { N } }
-\NewChemIUPAC \sulfur     { \textit { S } }
-\NewChemIUPAC \phosphorus { \textit { P } }
-
-\LetChemIUPAC \H  \hydrogen
-\LetChemIUPAC \O  \oxygen
-\LetChemIUPAC \N  \nitrogen
-\LetChemIUPAC \Sf \sulfur
-\LetChemIUPAC \P  \phosphorus
-
-% language specific settings
-\AtBeginDocument
-  {
-    \bool_if:NT \l__chemmacros_italian_bool
-      {
-        \NewChemIUPAC \sin  { \textit { sin } }
-        \NewChemIUPAC \ter  { \textit { ter } }
-      }
-  }
-
-% greek letters
-\NewChemIUPAC \a { \chemalpha }
-\NewChemIUPAC \b { \chembeta }
-\NewChemIUPAC \g { \chemgamma }
-\NewChemIUPAC \d { \chemdelta }
-\NewChemIUPAC \k { \chemkappa }
-\NewChemIUPAC \m { \chemmu }
-\NewChemIUPAC \n { \chemeta }
-\NewChemIUPAC \w { \chemomega }
-
-% \iupac (basically the same as bpchem's \IUPAC)
-% - allows multiple breaking points as compound names can get really long and
-%   especially in multicolumn documents can span more than two lines
-% - add a (very) little space before the hyphen and a little negative space
-%   after it
-% - add a little space at breaking points if not broken
-% - enables all naming commands regardless if they're definied otherwise or not
-\cs_new_protected:Nn \chemmacros_allow_hyphens:
-  {
-    \chemmacros_nobreak:
-    \skip_horizontal:N \c_zero_dim
-  }
-
-\dim_new:N  \l__chemmacros_iupac_hyphen_pre_dim
-\dim_set:Nn \l__chemmacros_iupac_hyphen_pre_dim { .01em }
-\dim_new:N  \l__chemmacros_iupac_hyphen_post_dim
-\dim_set:Nn \l__chemmacros_iupac_hyphen_post_dim { -.03em }
-\dim_new:N  \l__chemmacros_iupac_break_dim
-\dim_set:Nn \l__chemmacros_iupac_break_dim { .03em }
-
-\keys_define:nn { chemmacros / iupac }
-  {
-    hyphen-pre-space  .dim_set:N = \l__chemmacros_iupac_hyphen_pre_dim ,
-    hyphen-post-space .dim_set:N = \l__chemmacros_iupac_hyphen_post_dim ,
-    break-space       .dim_set:N = \l__chemmacros_iupac_break_dim
-  }
-
-\cs_new_protected:Nn \chemmacros_break_point_hyphen:
-  {
-    \chemmacros_nobreak:
-    \tex_discretionary:D { - } { }
-      {
-        \tex_kern:D \l__chemmacros_iupac_hyphen_pre_dim
-        -
-        \tex_kern:D \l__chemmacros_iupac_hyphen_post_dim
-      }
-    \chemmacros_allow_hyphens:
-  }
-
-\cs_new_protected:Npn \chemmacros_break_point:
-  {
-    \chemmacros_nobreak:
-    \tex_discretionary:D { - } { }
-      { \tex_kern:D \l__chemmacros_iupac_break_dim }
-    \chemmacros_allow_hyphens:
-  }
-
-\cs_new_protected:Npn \chemmacros_superscript:
-  { \mode_if_math:TF { \sb } { \textsuperscript } }
+% compatibility coding:
+\cs_new_protected:Npn \ChemCompatibility #1#2 \EndChemCompatibility
+  { \chemmacros_if_compatiblity:nnT {=} {#1} {#2} }
   
-\bool_new:N \l__chemmacros_inside_iupac_bool
-
-\group_begin:
-\char_set_catcode_active:N \~
-\char_set_lccode:nn {`~} {`|}
-\tl_to_lowercase:n { \group_end: \cs_set_eq:NN ~ } \chemmacros_break_point:
-
-\group_begin:
-\char_set_catcode_active:N \~
-\char_set_lccode:nn {`~} {`^}
-\tl_to_lowercase:n { \group_end: \cs_set_protected:Npn ~ }
-  { \chemmacros_superscript: }
-
-\group_begin:
-\char_set_catcode_active:N \|
-\char_set_catcode_active:N \^
-
-\cs_new_protected:Npn \chemmacros_iupac:n #1
-  {
-    \group_begin:
-      \bool_set_true:N \l__chemmacros_inside_iupac_bool
-      \chemmacros_make_iupac:
-      \chemmacros_ignore_spaces:
-      \cs_set_eq:NN \- \chemmacros_break_point_hyphen:
-      \chemmacros_define_deprecated:NN \| |
-      \chemmacros_define_deprecated:NN \^ ^
-      \tl_set_rescan:Nnn \l__chemmacros_tmpa_tl
-        {
-          \char_set_catcode_active:N \|
-          \char_set_catcode_active:N \^
-        }
-        {#1}
-      \l__chemmacros_tmpa_tl
-    \group_end:
-  }
-
-% \cs_new_protected:Npn \chemmacros_iupac_aux:n #1
-%   {
-%       #1
-%     \group_end:
-%   }
-\group_end:
-
-% Thanks to Joseph Wright and Enrico Gregorio for the help on the curious
-% redefinition of \- and the end of the compilation
-% see http://tex.stackexchange.com/q/42405/5049 for reference
-\cs_set_protected:Npx \| { \exp_not:o { \| } }
-\cs_set_protected:Npx \- { \exp_not:o { \- } }
-\cs_set_eq:NN \@dischyph \-
-
-\NewDocumentCommand \iupac { }
-  { \chemmacros_iupac:n }
-
-% --------------------------------------------------------------------------
-% latin phrases
-\tl_new:N  \l__chemmacros_latin_format_tl
-\tl_set:Nn \l__chemmacros_latin_format_tl { \itshape }
-
-\keys_define:nn { chemmacros / latin }
-  { format . tl_set:N = \l__chemmacros_latin_format_tl }
-
-\cs_new_protected:Npn \chemmacros_latin:n #1
-  { { \l__chemmacros_latin_format_tl #1 } }
-
-\prop_new:N \l__chemmacros_latin_prop
-
-\cs_new_protected:Npn \chemmacros_new_latin:Nn #1#2
-  {
-    \cs_if_free:NTF #1
-      {
-        \cs_new_protected:Npn #1
-          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
-        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
-      }
-      { \msg_error:nnn { chemmacros } { new-latin } { #1 } }
-  }
-
-\cs_new_protected:Npn \chemmacros_define_latin:Nn #1#2
-  {
-    \cs_if_free:NTF #1
-      {
-        \cs_new_protected:Npn #1
-          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
-        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
-      }
-      {
-        \cs_set_protected:Npn #1
-          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
-        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_renew_latin:Nn #1#2
-  {
-    \prop_if_in:NnTF \l__chemmacros_latin_prop { #1 }
-      { \cs_set:Npn #1 { \chemmacros_latin:n { #2 } \chemmacros_xspace: } }
-      { \msg_error:nnn { chemmacros } { renew-latin } { #1 } }
-  }
-
-\NewDocumentCommand \NewChemLatin { mm }
-  { \chemmacros_new_latin:Nn #1 { #2 } }
-
-\NewDocumentCommand \RenewChemLatin { mm }
-  { \chemmacros_renew_latin:Nn #1 { #2 } }
-
-\NewDocumentCommand \DeclareChemLatin { mm }
-  { \chemmacros_define_latin:Nn #1 { #2 } }
-
-\AtBeginDocument
-  {
-    \bool_if:NTF \l__chemmacros_chemstyle_bool
-      {
-        \AfterPackage* { chemstyle }
-          {
-            \cs_undefine:N \invacuo
-            \cs_set_eq:NN \chemmacros_latin:n \cst@latin
-          }
-      }
-      {
-        \cs_new_eq:NN  \latin \chemmacros_latin:n
-      }
-    \NewChemLatin \insitu   { in~situ }
-    \NewChemLatin \abinitio { ab~initio }
-    \NewChemLatin \invacuo  { in~vacuo }
-  }
-
-% --------------------------------------------------------------------------- %
-% acid / base
-\tl_new:N  \l__chemmacros_k_acid_tl
-\tl_new:N  \l__chemmacros_k_base_tl
-\tl_new:N  \l__chemmacros_k_water_tl
-
-% \bool_new:N \l__chemmacros_subscript_lowercase_bool
-
-\tl_set:Nn \l__chemmacros_k_acid_tl
-  { \chemmacros_translate:n {K-acid} }
-
-\tl_set:Nn \l__chemmacros_k_base_tl
-  { \chemmacros_translate:n {K-base} }
-
-\tl_set:Nn \l__chemmacros_k_water_tl
-  { \chemmacros_translate:n {K-water} }
-
-\keys_define:nn { chemmacros / acid-base }
-  {
-    p-style             .choice: ,
-    p-style / slanted   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textsl ,
-    p-style / italics   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textit ,
-    p-style / upright   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textup ,
-    K-acid              .tl_set:N = \l__chemmacros_k_acid_tl ,
-    K-base              .tl_set:N = \l__chemmacros_k_base_tl ,
-    K-water             .tl_set:N = \l__chemmacros_k_water_tl ,
-    subscript           .code:n   = \chemmacros_option_deprecated:n {#1}
-    % subscript / lowercase .code:n =
-    %   \bool_set_true:N \l__chemmacros_subscript_lowercase_bool ,
-    % subscript / uppercase .code:n =
-    %   \bool_set_false:N \l__chemmacros_subscript_lowercase_bool
-  }
-
-\cs_new_eq:NN \chemmacros_p_style:n \textup
-
-\cs_new_protected:Npn \Ka
-  {
-    \ensuremath
-      {
-        \chemmacros_detect_bold:n
-          {
-            K
-            \c_math_subscript_token
-              { \l__chemmacros_k_acid_tl }
-          }
-      }
-    \chemmacros_xspace:
-  }
-
-\cs_new_protected:Npn \Kb
-  {
-    \ensuremath
-      {
-        \chemmacros_detect_bold:n
-          {
-            K
-            \c_math_subscript_token
-              { \l__chemmacros_k_base_tl }
-          }
-      }
-    \chemmacros_xspace:
-  }
-
-\cs_new_protected:Npn \Kw
-  {
-    \ensuremath
-      {
-        \chemmacros_detect_bold:n
-          {
-            K
-            \c_math_subscript_token
-              { \l__chemmacros_k_water_tl }
-          }
-      }
-    \chemmacros_xspace:
-  }
-
-\cs_new_protected:Npn \chemmacros_p:n #1
-  {
-    \group_begin:
-      \mbox
-        {
-          \chemmacros_p_style:n { p }
-          \ensuremath { #1 }
-        }
-    \group_end:
-  }
-
-\NewDocumentCommand \p { m }
-  { \chemmacros_p:n { #1 } }
-
-\cs_new_protected:Npn \pH
-  {
-    \chemmacros_p:n { \chemmacros_chemformula:n { H } }
-    \chemmacros_xspace:
-  }
-
-\cs_new_protected:Npn \pOH
-  {
-    \chemmacros_p:n { \chemmacros_chemformula:n { OH } }
-    \chemmacros_xspace:
-  }
-
-\NewDocumentCommand \pKa { o }
-  {
-    \chemmacros_p:n
-      {
-        \Ka \IfNoValueF { #1 }
-          { {} \c_math_subscript_token { \chemmacros_detect_bold:n { #1 } } }
-      }
-    \chemmacros_xspace:
-  }
-
-\NewDocumentCommand \pKb { o }
-  {
-    \chemmacros_p:n
-      {
-        \Kb \IfNoValueF { #1 }
-          { {} \c_math_subscript_token { \chemmacros_detect_bold:n { #1 } } }
-      }
-    \chemmacros_xspace:
-  }
-
-% --------------------------------------------------------------------------
-% units
-\DeclareSIUnit { \atm        } { atm }
-\DeclareSIUnit { \atmosphere } { atm }
-\DeclareSIUnit { \calory     } { cal }
-\DeclareSIUnit { \cal        } { cal }
-
-\AtBeginDocument
-  {
-    \bool_if:NF \l__chemmacros_chemstyle_bool
-      {
-        \DeclareSIUnit { \cmc   } { \cubic\centi\metre }
-        \DeclareSIUnit { \molar } { \mole\per\cubic\deci\metre }
-        \DeclareSIUnit { \Molar } { \textsc{m} }
-      }
-  }
-
-\DeclareSIUnit { \moLar   } { \mole\per\liter }
-\DeclareSIUnit { \MolMass } { \gram\per\mole }
-\DeclareSIUnit { \normal  } { \textsc{n} }
-\DeclareSIUnit { \torr    } { torr }
-
-% --------------------------------------------------------------------------
-% reaction mechanisms
-% \mech[<type>]
-% <type> - substitutions: {}, 1, 2, se, 1e, 2e, ar
-%        - eliminations:  e, e1, e2, cb
-\tl_new:N \l__chemmacros_mech_type_tl
-\tl_new:N \l__chemmacros_mech_mol_tl
-\tl_new:N \l__chemmacros_mech_ar_tl
-
-\cs_new_protected:Npn \__chemmacros_set_mech:nnn #1#2#3
-  {
-    \tl_set:Nn \l__chemmacros_mech_type_tl { #1 }
-    \tl_set:Nn \l__chemmacros_mech_mol_tl  { #2 }
-    \tl_set:Nn \l__chemmacros_mech_ar_tl   { #3 }
-  }
-
-\keys_define:nn { chemmacros / mech }
-  {
-    type      .choice: ,
-    type /    .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {N} }
-            \c_math_toggle_token
-          }
-          { }
-      } ,
-    type / 1  .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {N} }
-            \c_math_toggle_token
-            1
-          }
-          { }
-      } ,
-    type / 2  .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {N} }
-            \c_math_toggle_token
-            2
-          }
-          { }
-      } ,
-    type / se .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {E} }
-            \c_math_toggle_token
-          }
-          { }
-      } ,
-    type / 1e .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {E} }
-            \c_math_toggle_token
-            1
-          }
-          { }
-      } ,
-    type / 2e .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {E} }
-            \c_math_toggle_token
-            2
-          }
-          { }
-      } ,
-    type / ar .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { S }
-          {
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {E} }
-            \c_math_toggle_token
-          }
-          { Ar - }
-      } ,
-    type / e  .code:n    =
-      { \__chemmacros_set_mech:nnn { E } { } { } } ,
-    type / e1 .code:n    =
-      { \__chemmacros_set_mech:nnn { E } { 1 } { } } ,
-    type / e2 .code:n    =
-      { \__chemmacros_set_mech:nnn { E } { 2 } { } } ,
-    type / cb .code:n    =
-      {
-        \__chemmacros_set_mech:nnn { E }
-          {
-            1
-            \c_math_toggle_token
-              \c_math_subscript_token { \text {cb} }
-            \c_math_toggle_token
-          }
-          { }
-      } ,
-    type      .default:n = 
-  }
-
-\cs_new_protected:Npn \chemmacros_mech:n #1
-  {
-    \tl_if_blank:nTF { #1 }
-      { \keys_set:nn { chemmacros / mech } { type } }
-      { \keys_set:nn { chemmacros / mech } { type = #1 } }
-    \mbox
-      {
-        \tl_use:N \l__chemmacros_mech_ar_tl
-        \tl_use:N \l__chemmacros_mech_type_tl
-        \tl_use:N \l__chemmacros_mech_mol_tl
-      }
-    \chemmacros_xspace:
-  }
-
-\NewDocumentCommand \mech { o }
-  {
-    \IfNoValueTF { #1 }
-      { \chemmacros_mech:n { } }
-      { \chemmacros_mech:n { #1 } }
-  }
-
-% --------------------------------------------------------------------------
-% oxidation numbers
-% \ox{<number>,<atom>}
-\bool_new:N       \l__chemmacros_ox_sign_bool
-\bool_new:N       \l__chemmacros_ox_integer_bool
-\bool_new:N       \l__chemmacros_ox_explicit_sign_bool
-\bool_set_false:N \l__chemmacros_ox_explicit_sign_bool
-\bool_new:N       \l__chemmacros_ox_format_roman_bool
-\bool_set_true:N  \l__chemmacros_ox_format_roman_bool
-\bool_new:N       \l__chemmacros_ox_decimal_marker_comma_bool
-\bool_set_false:N \l__chemmacros_ox_decimal_marker_comma_bool
-\bool_new:N       \l__chemmacros_ox_parse_bool
-\bool_set_true:N  \l__chemmacros_ox_parse_bool
-\bool_new:N       \l__chemmacros_ox_side_bool
-\bool_new:N       \l__chemmacros_ox_super_bool
-\bool_new:N       \l__chemmacros_ox_top_bool
-\bool_set_true:N  \l__chemmacros_ox_top_bool
-\bool_new:N       \l__chemmacros_ox_align_center_bool
-
-\int_new:N \l__chemmacros_ox_number_int
-\fp_new:N  \l__chemmacros_ox_number_fp
-
-\cs_new_protected:Npn \__chemmacros_ox_process_number:n #1
-  {
-    \bool_if:NTF \l__chemmacros_ox_parse_bool
-      {
-        \tl_if_in:nnTF { #1 } { / }
-          { \__chemmacros_ox_fraction:w #1 \q_stop }
-          {
-            \__chemmacros_ox_sign:n { #1 }
-            \__chemmacros_ox_value:n { #1 }
-          }
-      }
-      { #1 }
-  }
-
-\DeclareInstance { xfrac } { chemmacros-ox-frac } { text }
-  {
-    scale-factor        = 1.2 ,
-    denominator-bot-sep = -.5ex ,
-    numerator-top-sep   = -.3ex ,
-    slash-left-kern     = -.2em ,
-    slash-right-kern    = -.2em ,
-    slash-symbol-font   = lmr
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_fraction:w #1/#2 \q_stop
-  {
-    \bool_set_false:N \l__chemmacros_ox_format_roman_bool
-    \__chemmacros_ox_sign:n { #1 }
-    \bool_if:NTF \l__chemmacros_ox_side_bool
-      { \sfrac { \__chemmacros_ox_value:n { #1 } } { #2 } }
-      {
-        \sfrac [ chemmacros-ox-frac ]
-          { \__chemmacros_ox_value:n { #1 } }
-          { #2 }
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_sign:n #1
-  {
-    \fp_compare:nNnT { #1 } > { 0 }
-      {
-        \bool_if:NT \l__chemmacros_ox_explicit_sign_bool
-          { \c_math_toggle_token + \c_math_toggle_token }
-      }
-    \fp_compare:nNnT { #1 } = { 0 }
-      {
-        \bool_if:NT \l__chemmacros_ox_explicit_sign_bool
-          { \c_math_toggle_token \pm \c_math_toggle_token }
-      }
-    \fp_compare:nNnT { #1 } < { 0 }
-      { \c_math_toggle_token - \c_math_toggle_token }
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_value:n #1
-  {
-    \fp_set:Nn \l__chemmacros_ox_number_fp { abs(#1) }
-    \__chemmacros_ox_is_integer:V \l__chemmacros_ox_number_fp
-    \bool_if:NTF \l__chemmacros_ox_format_roman_bool
-      { \__chemmacros_fp_to_Roman:V \l__chemmacros_ox_number_fp }
-      {
-        \bool_if:NTF \l__chemmacros_ox_integer_bool
-          {
-            \c_math_toggle_token
-              \__chemmacros_fp_to_arabic:V \l__chemmacros_ox_number_fp
-            \c_math_toggle_token
-          }
-          {
-            \c_math_toggle_token
-              \__chemmacros_fp_show:V \l__chemmacros_ox_number_fp
-            \c_math_toggle_token
-          }
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_is_integer:n #1
-  {
-    \fp_set:Nn \l__chemmacros_tmpa_fp { round(#1 + 1 , 0 ) - 1 }
-    \fp_compare:nNnTF { \l__chemmacros_tmpa_fp } = { #1 }
-      { \bool_set_true:N \l__chemmacros_ox_integer_bool }
-      {
-        \bool_set_false:N \l__chemmacros_ox_integer_bool
-        \bool_set_false:N \l__chemmacros_ox_format_roman_bool
-      }
-  }
-\cs_generate_variant:Nn \__chemmacros_ox_is_integer:n { V }
-
-\cs_new_protected:Npn \__chemmacros_fp_to_Roman:n #1
-  {
-    \group_begin:
-      \fp_set:Nn \l__chemmacros_tmpa_fp { round(#1 , 0 ) }
-      \int_set:Nn \l__chemmacros_tmpa_int
-        { \fp_to_tl:N \l__chemmacros_tmpa_fp } 
-      \int_compare:nTF { \l__chemmacros_tmpa_int = 0 }
-        { 0 }
-        { \int_to_Roman:n { \l__chemmacros_tmpa_int } }
-    \group_end:
-  }
-\cs_generate_variant:Nn \__chemmacros_fp_to_Roman:n { V }
-
-\cs_new_protected:Npn \__chemmacros_fp_to_arabic:n #1
-  {
-    \group_begin:
-      \fp_set:Nn \l__chemmacros_tmpa_tl { #1 }
-      \fp_to_tl:N \l__chemmacros_tmpa_tl
-    \group_end:
-  }
-\cs_generate_variant:Nn \__chemmacros_fp_to_arabic:n { V }
-
-\cs_new_protected:Npn \__chemmacros_fp_show:n #1
-  {
-    \group_begin:
-      \fp_set:Nn \l__chemmacros_tmpa_tl { #1 }
-      \bool_if:NTF \l__chemmacros_ox_decimal_marker_comma_bool
-        {
-          \tl_set:Nx \l__chemmacros_tmpb_tl
-            { \fp_to_tl:N \l__chemmacros_tmpa_tl }
-          \tl_replace_once:Nnn \l__chemmacros_tmpb_tl { . } { {,} }
-          \tl_use:N \l__chemmacros_tmpb_tl
-        }
-        { \fp_to_tl:N \l__chemmacros_tmpa_tl }
-    \group_end:
-  }
-\cs_generate_variant:Nn \__chemmacros_fp_show:n { V }
-
-\cs_new_protected:Npn \__chemmacros_ox_write:nn #1#2
-  {
-    \tl_if_blank:nT { #1 }
-      { \msg_error:nnx { chemmacros } { ox } { oxidation~number~missing } }
-    \tl_if_blank:nT { #2 }
-      { \msg_error:nnx { chemmacros } { ox } { atom~missing } }
-    \ensuremath
-      {
-        \bool_if:NT \l__chemmacros_ox_super_bool
-          {
-            \chemmacros_text:n
-              {
-                #2
-                \c_math_toggle_token
-                  \c_math_superscript_token
-                    { \text { \tiny \__chemmacros_ox_process_number:n { #1 } } }
-                \c_math_toggle_token
-              }
-          }
-        \bool_if:NT \l__chemmacros_ox_side_bool
-          {
-            \chemmacros_text:n
-              { #2 ( \text { \__chemmacros_ox_process_number:n { #1 } } ) }
-          }
-        \bool_if:NT \l__chemmacros_ox_top_bool
-          {
-            \overset
-              {
-                \bool_if:NTF \l__chemmacros_ox_align_center_bool
-                  { \clap } { \rlap }
-                {
-                  \chemmacros_text:n
-                    { \tiny \__chemmacros_ox_process_number:n { #1 } }
-                }
-              }
-              { \chemmacros_text:n { #2 } }
-          }
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_pos_top:
-  {
-    \bool_set_true:N  \l__chemmacros_ox_top_bool
-    \bool_set_false:N \l__chemmacros_ox_super_bool
-    \bool_set_false:N \l__chemmacros_ox_side_bool
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_pos_super:
-  {
-    \bool_set_false:N \l__chemmacros_ox_top_bool
-    \bool_set_true:N  \l__chemmacros_ox_super_bool
-    \bool_set_false:N \l__chemmacros_ox_side_bool
-  }
-
-\cs_new_protected:Npn \__chemmacros_ox_pos_side:
-  {
-    \bool_set_false:N \l__chemmacros_ox_top_bool
-    \bool_set_false:N \l__chemmacros_ox_super_bool
-    \bool_set_true:N  \l__chemmacros_ox_side_bool
-  }
-
-\keys_define:nn { chemmacros / ox }
-  {
-    pos            .choice: ,
-    pos / top      .code:n     = \__chemmacros_ox_pos_top: ,
-    pos / super    .code:n     = \__chemmacros_ox_pos_super: ,
-    pos / side     .code:n     = \__chemmacros_ox_pos_side: ,
-    roman          .bool_set:N = \l__chemmacros_ox_format_roman_bool ,
-    roman          .default:n  = true ,
-    parse          .bool_set:N = \l__chemmacros_ox_parse_bool ,
-    parse          .default:n  = true ,
-    explicit-sign  .bool_set:N = \l__chemmacros_ox_explicit_sign_bool ,
-    explicit-sign  .default:n  = true ,
-    decimal-marker .choice: ,
-    decimal-marker / comma .code:n =
-      { \bool_set_true:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
-    decimal-marker / point .code:n =
-      { \bool_set_false:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
-    align          .choice: ,
-    align / center .code:n    = \bool_set_true:N \l__chemmacros_ox_align_center_bool ,
-    align / right  .code:n    = \bool_set_false:N \l__chemmacros_ox_align_center_bool
-  }
-
-% \ox[<keyval>]{<num>,<atom>}
-% \ox*[<keyval>]{<num>,<atom>} => always number on the side
-\cs_new_protected:Npn \chemmacros_ox:nnnn #1#2#3#4
-  {
-    \group_begin:
-      \tl_if_blank:nF { #1 } { \__chemmacros_ox_pos_super: }
-      \keys_set:nn { chemmacros / ox } { #2 }
-      \__chemmacros_ox_write:nn { #3 } { #4 }
-    \group_end:
-  }
-
-\NewDocumentCommand \ox { s o > { \SplitArgument { 1 } { , } } m }
-  {
-    \IfBooleanTF { #1 }
-      {
-        \IfNoValueTF { #2 }
-          { \chemmacros_ox:nnnn { #1 } {    } #3 }
-          { \chemmacros_ox:nnnn { #1 } { #2 } #3 }
-      }
-      {
-        \IfNoValueTF { #2 }
-          { \chemmacros_ox:nnnn { } {    } #3 }
-          { \chemmacros_ox:nnnn { } { #2 } #3 }
-      }
-  }
-
-% --------------------------------------------------------------------------- %
-% - oxidation arrows
-\tl_new:N   \l__chemmacros_redox_begin_tl
-\tl_new:N   \l__chemmacros_redox_end_tl
-\tl_new:N   \l__chemmacros_redox_tikz_tl
-\tl_new:N   \l__chemmacros_redox_shift_tl
-\tl_new:N   \l__chemmacros_redox_anchor_tl
-\tl_new:N   \l__chemmacros_redox_side_tl
-
-\fp_new:N   \l__chemmacros_redox_shift_fp
-
-\dim_new:N  \l__chemmacros_redox_sep_dim
-\dim_new:N  \l__chemmacros_redox_sep_default_dim
-\dim_set:Nn \l__chemmacros_redox_sep_default_dim { .2em }
-\dim_new:N  \l__chemmacros_redox_dist_dim
-\dim_set:Nn \l__chemmacros_redox_dist_dim {.6em}
-
-% place and name nodes:
-% \OX{<name>,<atom>}
-\NewDocumentCommand \OX { > { \SplitArgument { 1 } { , } } m }
-  { \chemmacros_redox_partner:nn #1 }
-
-\cs_new_protected:Npn \chemmacros_redox_partner:nn #1#2
-  {
-    \chemformula_latex_if:nTF { measuring@ }
-      {
-        \group_begin:
-        \tikz[baseline=(#1.base)]
-          { \node [inner~sep=0pt] (#1) { #2 } ; }
-        \group_end:
-      }
-      {
-        \tl_if_blank:nT { #1 }
-          { \msg_error:nnx { chemmacros } { OX } { node~name~missing } }
-        \tl_if_blank:nT { #2 }
-          { \msg_error:nnx { chemmacros } { OX } { atom~missing } }
-        \tikz[baseline=(#1.base),remember~picture]
-          { \node [inner~sep=0pt] (#1) { #2 } ; }
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_redox_coordinates:nn #1#2
-  {
-    \tl_set:Nn \l__chemmacros_redox_begin_tl { #1 }
-    \tl_set:Nn \l__chemmacros_redox_end_tl   { #2 }
-  }
-
-\cs_new_protected:Npn \chemmacros_redox:nnnnn #1#2#3#4#5
-  {
-    \tl_clear:N \l__chemmacros_redox_begin_tl
-    \tl_clear:N \l__chemmacros_redox_end_tl
-    \tl_clear:N \l__chemmacros_redox_tikz_tl
-    \__chemmacros_redox_coordinates:nn { #1 } { #2 }
-    \tl_if_blank:nF { #3 }
-      { \tl_set:Nn \l__chemmacros_redox_tikz_tl { #3 } }
-    \tl_if_blank:nTF { #4 }
-      {
-        \fp_set:Nn \l__chemmacros_redox_shift_fp  { 1 }
-        \tl_set:Nn \l__chemmacros_redox_anchor_tl { above }
-        \tl_set:Nn \l__chemmacros_redox_side_tl { north }
-        \dim_set_eq:NN
-          \l__chemmacros_redox_sep_dim
-          \l__chemmacros_redox_sep_default_dim
-      }
-      {
-        \fp_compare:nNnTF { #4 } < { 0 }
-          {
-            \tl_set:Nn \l__chemmacros_redox_anchor_tl { below }
-            \tl_set:Nn \l__chemmacros_redox_side_tl { south }
-            \exp_args:NNo \dim_set:Nn \l__chemmacros_redox_sep_dim
-              { - \l__chemmacros_redox_sep_default_dim }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_redox_anchor_tl { above }
-            \tl_set:Nn \l__chemmacros_redox_side_tl { north }
-            \dim_set_eq:NN
-              \l__chemmacros_redox_sep_dim
-              \l__chemmacros_redox_sep_default_dim
-          }
-        \fp_set:Nn \l__chemmacros_redox_shift_fp { #4 }
-      }
-      \tl_set:Nn \l__chemmacros_redox_shift_tl
-        { \fp_to_tl:N \l__chemmacros_redox_shift_fp }
-    \tikz[remember~picture,overlay]
-      {
-        \chemmacros_tikz_draw:f { \tl_use:N \l__chemmacros_redox_tikz_tl }
-        ($
-          (\l__chemmacros_redox_begin_tl .
-          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
-        $)
-        -- 
-        ++(0,\l__chemmacros_redox_shift_tl * \l__chemmacros_redox_dist_dim) -|
-        node [pos=.25,\l__chemmacros_redox_anchor_tl] { { #5 } }
-        ($
-          (\l__chemmacros_redox_end_tl .
-          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
-        $) ;
-      }
-  }
-
-\NewDocumentCommand \redox { > { \SplitArgument { 1 } { , } } r() o o G{} }
-  {
-    \IfNoValueT { #1 }
-      {
-        \msg_error:nnx { chemmacros } { redox }
-          { You~need~to~specify~coordinates }
-      }
-    \IfNoValueTF { #2 }
-      { \chemmacros_redox:nnnnn #1 { } { } { #4 } }
-      {
-        \IfNoValueTF { #3 }
-          { \chemmacros_redox:nnnnn #1 { #2 } {    } { #4 } }
-          { \chemmacros_redox:nnnnn #1 { #2 } { #3 } { #4 } }
-      }
-  }
-
-% redox-keys
-\keys_define:nn { chemmacros / redox }
-  {
-    dist .dim_set:N = \l__chemmacros_redox_dist_dim ,
-    dist .default:n = { .6em } ,
-    sep  .dim_set:N = \l__chemmacros_redox_sep_default_dim ,
-    sep  .default:n = { .2em }
-  }
-
-% --------------------------------------------------------------------------- %
-% spectroscopy
-\tl_new:N  \g__chemmacros_nmr_isotope_tl
-\tl_new:N  \l__chemmacros_nmr_isotope_default_tl
-\tl_set:Nn \l__chemmacros_nmr_isotope_default_tl { 1 }
-\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_tl
-\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_pre_tl
-\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_pre_tl { ( }
-\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_post_tl
-\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_post_tl { ) }
-\tl_new:N  \l__chemmacros_nmr_coupling_bonds_tl
-\tl_new:N  \l__chemmacros_nmr_coupling_bonds_pre_tl
-\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_pre_tl { }
-\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_post_tl { \! }
-\tl_new:N  \l__chemmacros_nmr_coupling_symbol_tl
-\tl_set:Nn \l__chemmacros_nmr_coupling_symbol_tl { J }
-\tl_new:N  \g__chemmacros_nmr_element_coupled_tl
-\tl_new:N  \g__chemmacros_nmr_element_tl
-\tl_new:N  \l__chemmacros_nmr_element_default_tl
-\tl_set:Nn \l__chemmacros_nmr_element_default_tl { H }
-\tl_new:N  \l__chemmacros_nmr_format_tl
-\tl_new:N  \l__chemmacros_nmr_delta_tl
-\tl_new:N  \l__chemmacros_nmr_coupling_unit_tl
-\tl_set:Nn \l__chemmacros_nmr_coupling_unit_tl { \hertz }
-\tl_new:N  \l__chemmacros_nmr_unit_tl
-\tl_set:Nn \l__chemmacros_nmr_unit_tl { \mega\hertz }
-\tl_new:N  \l__chemmacros_nmr_list_setup_tl
-\tl_set:Nn \l__chemmacros_nmr_list_setup_tl
-  {
-    \topsep\z@skip \partopsep\z@skip 
-    \itemsep\z@ \parsep\z@ \itemindent\z@
-    \leftmargin\z@
-  }
-\tl_new:N  \l__chemmacros_nmr_position_tl
-\tl_new:N  \l__chemmacros_nmr_element_method_connector_tl
-\tl_set:Nn \l__chemmacros_nmr_element_method_connector_tl {-}
-\tl_new:N  \l__chemmacros_nmr_method_tl
-\tl_set:Nn \l__chemmacros_nmr_method_tl {NMR}
-
-\bool_new:N      \l__chemmacros_nmr_coupling_nuclei_sub_bool
-\bool_new:N      \l__chemmacros_nmr_frequency_bool
-\bool_new:N      \l__chemmacros_nmr_solvent_bool
-\bool_new:N      \l__chemmacros_nmr_delimiters_bool
-\bool_new:N      \l__chemmacros_nmr_comma_bool
-\bool_new:N      \l__chemmacros_nmr_inner_bool
-\bool_new:N      \l__chemmacros_nmr_position_side_bool
-\bool_new:N      \l__chemmacros_nmr_parse_bool
-\bool_set_true:N \l__chemmacros_nmr_parse_bool
-\bool_new:N      \l__chemmacros_nmr_list_bool
-\bool_new:N      \l__chemmacros_nmr_use_equal_bool
-\bool_new:N      \l__chemmacros_nmr_custom_command_active_bool
-\bool_new:N      \l__chemmacros_nmr_custom_command_used_bool
-
-\cs_new_protected:Npn \__chemmacros_nmr_nucleus:nn #1#2
-  {
-    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl { #1 }
-    \tl_if_in:nnTF { #2 } { [ }
-      { \__chemmacros_nmr_element:w #2 \q_stop }
-      {
-        \tl_gset:No \g__chemmacros_nmr_element_tl { #2 }
-        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
-      }
-  }
-\cs_generate_variant:Nn \__chemmacros_nmr_nucleus:nn { VV }
-
-\cs_new_protected:Npn \__chemmacros_nmr_nucleus:w #1,#2 \q_stop
-  {
-    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl { #1 }
-    \tl_if_in:nnTF { #2 } { [ }
-      { \__chemmacros_nmr_element:w #2 \q_stop }
-      {
-        \tl_gset:No \g__chemmacros_nmr_element_tl { #2 }
-        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_element:w #1[#2] \q_stop
-  {
-    \tl_gset:Nn \g__chemmacros_nmr_element_tl { #1 }
-    \tl_gset:Nn \g__chemmacros_nmr_element_coupled_tl { #2 }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_default_nucleus:w #1,#2 \q_stop
-  {
-    \tl_set:Nn \l__chemmacros_nmr_isotope_default_tl { #1 }
-    \tl_set:Nn \l__chemmacros_nmr_element_default_tl { #2 }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_base:nn #1#2
-  {
-    \tl_if_blank:VF \g__chemmacros_nmr_element_coupled_tl
-      {
-        \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl { \{ }
-        \tl_put_right:Nn \g__chemmacros_nmr_element_coupled_tl { \} }
-      }
-    \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl { #2 }
-    \iupac { ^ { #1 } }
-    \bool_if:NTF \l__chemmacros_nmr_parse_bool
-      { \chemformula_ch:nV {} \g__chemmacros_nmr_element_coupled_tl }
-      { \chemmacros_atom:V \g__chemmacros_nmr_element_coupled_tl }
-    \tl_use:N \l__chemmacros_nmr_element_method_connector_tl
-    \tl_use:N \l__chemmacros_nmr_method_tl
-  }
-\cs_generate_variant:Nn \__chemmacros_nmr_base:nn { VV }
-
-\cs_new_protected:Npn \__chemmacros_nmr_frequency:n #1
-  {
-    \tl_if_in:nnTF { #1 } { , }
-      { \__chemmacros_nmr_frequency_aux_i:w #1 \q_stop }
-      { \__chemmacros_nmr_frequency_aux_ii:n { #1 } }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_i:w #1,#2 \q_stop
-  { \SI { #1 } { #2 } }
-
-\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_ii:n #1
-  { \SI { #1 } { \tl_use:N \l__chemmacros_nmr_unit_tl } }
-
-\cs_new_eq:NN \__chemmacros_nmr_number:n \use:n
-\cs_new_eq:NN \__chemmacros_nmr_position:n \use:n
-
-\keys_define:nn { chemmacros / nmr }
-  {
-    unit          .tl_set:N      = \l__chemmacros_nmr_unit_tl ,
-    unit          .default:n     = \mega\hertz ,
-    nucleus       .code:n        =
-      { \__chemmacros_nmr_default_nucleus:w #1 \q_stop } ,
-    nucleus       .default:n     = { 1,H } ,
-    format        .tl_set:N      = \l__chemmacros_nmr_format_tl ,
-    method        .tl_set:N      = \l__chemmacros_nmr_method_tl ,
-    connector     .tl_set:N      = \l__chemmacros_nmr_element_method_connector_tl ,
-    pos-number    .choice: ,
-    pos-number / sub  .code:n =
-      \tl_set:Nn \l__chemmacros_nmr_position_tl { _ }
-      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
-    pos-number / super .code:n =
-      \tl_set:Nn \l__chemmacros_nmr_position_tl { ^ }
-      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
-    pos-number / side .code:n =
-      \tl_set:Nn \l__chemmacros_nmr_position_tl { - }
-      \bool_set_true:N \l__chemmacros_nmr_position_side_bool ,
-    coupling-unit .tl_set:N   = \l__chemmacros_nmr_coupling_unit_tl ,
-    coupling-pos  .choice: ,
-    coupling-pos / sub .code:n =
-      \bool_set_true:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
-    coupling-pos / side .code:n =
-      \bool_set_false:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
-    coupling-nuclei-pre  .tl_set:N =
-      \l__chemmacros_nmr_coupling_nuclei_pre_tl ,
-    coupling-nuclei-post .tl_set:N =
-      \l__chemmacros_nmr_coupling_nuclei_post_tl ,
-    coupling-bonds-pre   .tl_set:N =
-      \l__chemmacros_nmr_coupling_bonds_pre_tl ,
-    coupling-bonds-post  .tl_set:N =
-      \l__chemmacros_nmr_coupling_bonds_post_tl ,
-    coupling-symbol .tl_set:N    =
-      \l__chemmacros_nmr_coupling_symbol_tl ,
-    atom-number-cs .code:n       =
-      \cs_set_eq:NN \__chemmacros_nmr_number:n #1 ,
-    coupling-pos-cs .code:n      =
-      \cs_set_eq:NN \__chemmacros_nmr_position:n #1 ,
-    parse         .bool_set:N    = \l__chemmacros_nmr_parse_bool ,
-    delta         .code:n        =
-      \tl_set:Nn \l__chemmacros_nmr_delta_tl { \, #1 } ,
-    list          .bool_set:N    = \l__chemmacros_nmr_list_bool ,
-    list          .default:n     = true ,
-    list-setup    .tl_set:N      = \l__chemmacros_nmr_list_setup_tl ,
-    use-equal     .bool_set:N    = \l__chemmacros_nmr_use_equal_bool ,
-    use-equal     .default:n     = true
-  }
-
-\prop_new:N \l__chemmacros_nmr_prop
-
-\cs_new_protected:Npn \chemmacros_new_nmr:Nn #1#2
-  {
-    \bool_if:nTF
-      {
-        \prop_if_in_p:Nn \l__chemmacros_nmr_prop { #1 }
-        ||
-        \cs_if_exist_p:N #1
-      }
-      { \msg_error:nnn { chemmacros } { new-nmr } { #1 } }
-      {
-        \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
-        \NewDocumentCommand #1 { s }
-          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_define_nmr:Nn #1#2
-  {
-    \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
-    \cs_if_exist:NTF #1
-      {
-        \RenewDocumentCommand #1 { s }
-          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
-      }
-      {
-        \NewDocumentCommand #1 { s }
-          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_renew_nmr:Nn #1#2
-  {
-    \bool_if:nTF
-      {
-        \prop_if_in_p:Nn \l__chemmacros_nmr_prop { #1 }
-        &&
-        \cs_if_exist_p:N #1
-      }
-      {
-        \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
-        \RenewDocumentCommand #1 { s }
-          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
-      }
-      { \msg_error:nnn { chemmacros } { renew-nmr } { #1 } }
-  }
-
-\NewDocumentCommand \NewChemNMR { mm }
-  { \chemmacros_new_nmr:Nn #1 { #2 } }
-
-\NewDocumentCommand \RenewChemNMR { mm }
-  { \chemmacros_renew_nmr:Nn #1 { #2 } }
-
-\NewDocumentCommand \DeclareChemNMR { mm }
-  { \chemmacros_define_nmr:Nn #1 { #2 } }
-
-\NewDocumentCommand \NMR { s G{} D(){} O{} }
-  {
-    \IfBooleanTF { #1 }
-      { \chemmacros_nmr:nnnn { * } { #2 } { #3 } { #4 } }
-      { \chemmacros_nmr:nnnn {   } { #2 } { #3 } { #4 } }
-  }
-
-\AtBeginDocument
-  {
-    % \NMR{<num>,<elem>}(<num>,<unit>)[<solvent>] ALL arguments are optional
-    % \NMR* same but without ": $\delta$" at end
-    \cs_new_protected:Npn \chemmacros_nmr:nnnn #1#2#3#4
-      {
-        \bool_if:NT \l__chemmacros_nmr_list_bool { \item \scan_stop: }
-        \group_begin:
-          \chemmacros_leave_vmode:
-          \bool_set_false:N \l__chemmacros_nmr_frequency_bool
-          \bool_set_false:N \l__chemmacros_nmr_solvent_bool
-          \tl_if_empty:nF { #3 }
-            { \bool_set_true:N \l__chemmacros_nmr_frequency_bool }
-          \tl_if_empty:nF { #4 }
-            { \bool_set_true:N \l__chemmacros_nmr_solvent_bool }
-          \bool_if:nT
-            {
-              \l__chemmacros_nmr_frequency_bool
-              ||
-              \l__chemmacros_nmr_solvent_bool
-            }
-            { \bool_set_true:N \l__chemmacros_nmr_delimiters_bool }
-          \bool_if:nT
-            {
-              \l__chemmacros_nmr_frequency_bool
-              &&
-              \l__chemmacros_nmr_solvent_bool
-            }
-            { \bool_set_true:N \l__chemmacros_nmr_comma_bool }
-          \tl_if_empty:nTF { #2 }
-            {
-              \__chemmacros_nmr_nucleus:VV
-                \l__chemmacros_nmr_isotope_default_tl
-                \l__chemmacros_nmr_element_default_tl
-            }
-            { \__chemmacros_nmr_nucleus:w #2 \q_stop }
-          \mode_if_math:TF
-            {
-              \text
-                {
-                  \group_begin:
-                    \tl_use:N \l__chemmacros_nmr_format_tl
-                    \__chemmacros_nmr_base:VV
-                      \g__chemmacros_nmr_isotope_tl
-                      \g__chemmacros_nmr_element_tl
-                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
-                      { ~ ( }
-                    \bool_if:NT \l__chemmacros_nmr_frequency_bool
-                      { \__chemmacros_nmr_frequency:n { #3 } }
-                    \bool_if:NT \l__chemmacros_nmr_comma_bool
-                      { , ~ }
-                    \bool_if:NT \l__chemmacros_nmr_solvent_bool
-                      { \chemmacros_atom:n { #4 } }
-                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
-                      { ) }
-                    \tl_if_blank:nT { #1 } { : ~ }
-                  \group_end:
-                }
-              \tl_if_blank:nT { #1 }
-                {
-                  \delta
-                  \text { \l__chemmacros_nmr_delta_tl }
-                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool { = }
-                }
-            }
-            {
-              \group_begin:
-                \tl_use:N \l__chemmacros_nmr_format_tl
-                \__chemmacros_nmr_base:VV
-                  \g__chemmacros_nmr_isotope_tl
-                  \g__chemmacros_nmr_element_tl
-                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
-                  { ~ ( }
-                \bool_if:NT \l__chemmacros_nmr_frequency_bool
-                  { \__chemmacros_nmr_frequency:n { #3 } }
-                \bool_if:NT \l__chemmacros_nmr_comma_bool
-                  { , ~ }
-                \bool_if:NT \l__chemmacros_nmr_solvent_bool
-                  {
-                    \bool_if:NTF \l__chemmacros_nmr_parse_bool
-                      { \chemformula_ch:nn { } { #4 } }
-                      { #4 }
-                  }
-                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
-                  { ) }
-                \tl_if_blank:nT { #1 } { : }
-              \group_end:
-              \tl_if_blank:nT { #1 }
-                {
-                  \tl_use:N \c_space_tl
-                  \c_math_toggle_token
-                    \delta
-                  \c_math_toggle_token
-                  \l__chemmacros_nmr_delta_tl
-                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool { ~ = }
-                }
-              \bool_if:NF \l__chemmacros_nmr_comma_bool
-                { \tl_if_blank:nT { #1 } { \chemmacros_xspace: } }
-            }
-        \group_end:
-      }
-  }
-
-\NewDocumentCommand \chemmacros_data:w { smo }
-  {
-    \bool_if:NT \l__chemmacros_nmr_list_bool { \item }
-    {
-      \tl_use:N \l__chemmacros_nmr_format_tl #2
-      \IfNoValueF { #3 } { ~ ( #3 ) }
-      \IfBooleanT { #1 } { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { : } }
-    }
-    \IfBooleanF { #1 } { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { ~ = } }
-  }
-
-\cs_new_protected:Npn \chemmacros_val:n #1
-  {
-    \tl_if_in:nnTF { #1 } { -- }
-      { \chemmacros_val_aux:w #1 \q_nil }
-      { \num { #1 } }
-  }
-
-\cs_new_protected:Npn \chemmacros_val_aux:w #1--#2 \q_nil
-  { \numrange { #1 } { #2 } }
-
-\NewDocumentEnvironment { experimental } { o }
-  {
-    \group_begin:
-    \IfNoValueF { #1 } { \keys_set:nn { chemmacros / nmr } { #1 } }
-    \bool_set_true:N \l__chemmacros_nmr_inner_bool
-    \cs_set_eq:NN \#    \chemmacros_nmr_number:n
-    \cs_set_eq:NN \pos  \chemmacros_nmr_position:n
-    \cs_set_eq:NN \J    \chemmacros_nmr_coupling:w
-    \cs_set_eq:NN \data \chemmacros_data:w
-    \cs_set_eq:NN \val  \chemmacros_val:n
-    \bool_if:NT \l__chemmacros_nmr_list_bool
-      { \list {} { \l__chemmacros_nmr_list_setup_tl } }
-  }
-  {
-    \bool_if:NT \l__chemmacros_nmr_list_bool
-      { \endlist }
-    \group_end:
-    \chemmacros_ignore_spaces:
-  }
-
-\cs_new_protected:Npn \chemmacros_nmr_number:n #1
-  {
-    \__chemmacros_nmr_number:n { #1 } \,
-    \chemmacros_atom:V \g__chemmacros_nmr_element_tl
-  }
-
-\cs_new_protected:Npn \chemmacros_nmr_position:n #1
-  {
-    \chemmacros_chemformula:x
-      {
-        \exp_not:V \g__chemmacros_nmr_element_tl
-        \bool_if:NF \l__chemmacros_nmr_position_side_bool
-          {
-            \exp_not:V \l__chemmacros_nmr_position_tl
-            \exp_not:n { {#1} }
-          }
-      }
-    \bool_if:NT \l__chemmacros_nmr_position_side_bool
-      {
-        \tl_use:N \l__chemmacros_nmr_position_tl
-        \__chemmacros_nmr_position:n { #1 }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_nmr_coupling:w
-  {
-    \tl_clear:N \l__chemmacros_nmr_coupling_nuclei_tl
-    \tl_clear:N \l__chemmacros_nmr_coupling_bonds_tl
-    \peek_meaning:NTF (
-      { \__chemmacros_nmr_coupling:w }
-      { \__chemmacros_nmr_coupling_aux_i:w }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_coupling:w (#1;#2)
-  {
-    \tl_set:Nn \l__chemmacros_nmr_coupling_bonds_tl
-      {
-        \l__chemmacros_nmr_coupling_bonds_pre_tl
-        #1
-        \l__chemmacros_nmr_coupling_bonds_post_tl
-      }
-    \bool_if:NTF \l__chemmacros_nmr_coupling_nuclei_sub_bool
-      {
-        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
-          {
-            \c_math_subscript_token
-              { \chemmacros_chemformula:n {#2} }
-          }
-      }
-      {
-        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
-          {
-            \l__chemmacros_nmr_coupling_nuclei_pre_tl
-            \chemmacros_chemformula:n {#2}
-            \l__chemmacros_nmr_coupling_nuclei_post_tl
-          }
-      }
-    \__chemmacros_nmr_coupling_aux_i:w
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_i:w
-  {
-    \peek_meaning:NTF [
-      { \__chemmacros_nmr_coupling_aux_ii:w }
-      { \__chemmacros_nmr_coupling_aux_iii:n }
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_ii:w [#1]#2
-  {
-    \group_begin:
-      \sisetup
-        {
-          list-final-separator={,~},
-          list-pair-separator={,~},
-          list-units=single
-        }
-      \c_math_toggle_token
-        ^{ \l__chemmacros_nmr_coupling_bonds_tl }
-        \l__chemmacros_nmr_coupling_symbol_tl
-        \l__chemmacros_nmr_coupling_nuclei_tl = \SIlist{#2}{#1}
-      \c_math_toggle_token
-    \group_end:
-  }
-
-\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_iii:n #1
-  {
-    \group_begin:
-      \sisetup
-        {
-          list-final-separator={,~},
-          list-pair-separator={,~},
-          list-units=single
-        }
-      \c_math_toggle_token
-         ^{ \l__chemmacros_nmr_coupling_bonds_tl }
-         \l__chemmacros_nmr_coupling_symbol_tl
-         \l__chemmacros_nmr_coupling_nuclei_tl
-         = \exp_args:Nno \SIlist { #1 } { \l__chemmacros_nmr_coupling_unit_tl }
-      \c_math_toggle_token
-    \group_end:
-  }
-
-% --------------------------------------------------------------------------
-% deprecated mhName:
-\keys_define:nn { chemmacros }
-  { mhName .code:n = \chemmacros_option_deprecated:n { mhName } }
-
-% --------------------------------------------------------------------------- %
-% - phases
-\bool_new:N \l__chemmacros_phases_sub_bool
-\dim_new:N  \l__chemmacros_phases_space_dim
-\dim_set:Nn \l__chemmacros_phases_space_dim { .1333 em }
-\prop_new:N \l__chemmacros_phases_prop
-\prop_new:N \l__chemmacros_phases_german_prop
-
-\keys_define:nn { chemmacros / phases }
-  {
-    pos        .choice: ,
-    pos / sub  .code:n    = \bool_set_true:N \l__chemmacros_phases_sub_bool ,
-    pos / side .code:n    = \bool_set_false:N \l__chemmacros_phases_sub_bool ,
-    space      .dim_set:N = \l__chemmacros_phases_space_dim
-  }
-
-\cs_new_protected:Npn \chemmacros_new_phase:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \cs_if_free:NF #1
-      { \msg_error:nnn {chemmacros} {new-phase} {#1} }
-    \exp_args:Nx \@trnslt@declare@translation
-      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
-    \__chemmacros_define_phase:Nx #1
-      {
-        \exp_not:N \chemmacros_translate:n
-          { phase-\l__chemmacros_tmpa_tl }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_define_phase:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \exp_args:Nx \@trnslt@declare@translation
-      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
-    \__chemmacros_define_phase:Nx #1
-      {
-        \exp_not:N \chemmacros_translate:n
-          { phase-\l__chemmacros_tmpa_tl }
-      }
-  }
-
-\cs_new_protected:Npn \chemmacros_renew_phase:Nn #1#2
-  {
-    \tl_set:Nx \l__chemmacros_tmpa_tl
-      { \chemmacros_remove_backslash:N #1 }
-    \cs_if_exist:NF #1
-      { \msg_error:nnn {chemmacros} {renew-phase} {#1} }
-    \exp_args:Nx \@trnslt@declare@translation
-      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
-    \__chemmacros_define_phase:Nx #1
-      {
-        \exp_not:N \chemmacros_translate:n
-          { phase-\l__chemmacros_tmpa_tl }
-      }
-  }
-
-\NewDocumentCommand \NewChemPhase { mom }
-  { \chemmacros_new_phase:Nn #1 {#3} }
-
-\NewDocumentCommand \DeclareChemPhase { mom }
-  { \chemmacros_define_phase:Nn #1 {#3} }
-
-\NewDocumentCommand \RenewChemPhase { mom }
-  { \chemmacros_renew_phase:Nn #1 {#3} }
-
-\cs_new_protected:Npn \__chemmacros_define_phase:Nn #1#2
-  {
-    \cs_if_exist:NF #1 { \cs_new:Npn #1 {} }
-    \DeclareDocumentCommand #1 { o }
-      {
-        \bool_if:NTF \l__chemmacros_phases_sub_bool
-          {
-            \bool_if:NTF \l_chemformula_inside_ch_bool
-              { \chemformula_subscript:n { ( #2 \IfNoValueF {##1} {,~##1} ) } }
-              {
-                \ensuremath
-                  {
-                    \c_math_subscript_token
-                    { \text { ( #2 \IfNoValueF {##1} {,~##1} ) } }
-                  }
-              }
-          }
-          {
-            \ensuremath
-              {
-                \skip_horizontal:N \l__chemmacros_phases_space_dim
-                \text { ( #2 \IfNoValueF {##1} {,~##1} ) }
-              }
-          }
-      }
-  }
-\cs_generate_variant:Nn \__chemmacros_define_phase:Nn { Nx }
-
-\NewChemPhase \sld {s}
-\NewChemPhase \lqd {l}
-\NewChemPhase \gas {g}
-\NewChemPhase \aq  {aq}
-
-\cs_new_protected:Npn \chemmacros_phase:n #1
-  {
-    \bool_if:NTF \l__chemmacros_phases_sub_bool
-      { \ensuremath { \c_math_subscript_token { \text { (#1) } } } }
-      {
-        \ensuremath
-          {
-            \skip_horizontal:N \l__chemmacros_phases_space_dim
-            \text { (#1) }
-          }
-      }
-  }
-
-\NewDocumentCommand \phase { m }
-  { \chemmacros_phase:n {#1} }
-
-% --------------------------------------------------------------------------
-% reaction environments
-\cs_new_protected:Npn \__chemmacros_record_for_lor:nnnnn #1#2#3#4#5
-  {
-    \tl_if_eq:nnT { #1 } { reaction }
-      {
-        \group_begin:
-          % we need to prevent \Hy@make@anchor from being written to the lor
-          % file:
-          \bool_if:NT \l__chemmacros_hyperref_bool
-            { \cs_set:Npn \Hy@make@anchor {} }
-          \addcontentsline { lor } { reaction }
-            {
-              \tl_use:N \l__chemmacros_reaction_lorname_tl
-              \tl_use:N \c_space_tl
-              #2 #3 #4 #5
-              \tl_use:N \g__chemmacros_reaction_description_tl
-            }
-          \tl_gclear:N \g__chemmacros_reaction_description_tl
-        \group_end:
-      }
-  }
-
-% redefine mathtools' command \MT_define_tagform:nwnn to ensure we add an
-% entry to the list of reactions even if the user redefines the reaction tag
-% this should probably be done via patching...
-\AfterPackage* { mathtools }
-  {
-    \cs_set_protected:Npn \MT_define_tagform:nwnn #1[#2]#3#4
-      {
-        \@namedef{MT_tagform_#1:n}##1
-          {
-            % this is the original part:
-            \maketag@@@{#3\ignorespaces#2{##1}\unskip\@@italiccorr#4}
-            % this is added => this disturbs hyperref:
-            \__chemmacros_record_for_lor:nnnnn
-              { #1 } { #3 } { #2 } { ##1 } { #4 }
-          }
-      }
-  }
-
-\tl_new:N \g__chemmacros_reaction_description_tl
-
-\cs_new_protected:Npn \chemmacros_add_reaction_description:n #1
-  {
-    \tl_if_blank:nF { #1 }
-      { \tl_gset:Nn \g__chemmacros_reaction_description_tl { : ~ #1 } }
-  }
-
-\NewDocumentCommand \AddRxnDesc { m }
-  { \chemmacros_add_reaction_description:n { #1 } }
-
-% define \listofreactions
-\tl_new:N \l__chemmacros_reaction_lorname_tl
-\tl_new:N \reactionlistname
-\tl_new:N \l__chemmacros_reaction_heading_tl
-
-\cs_new:Npn \__chemmacros_reaction_heading:n #1
-  { \l__chemmacros_reaction_heading_tl { #1 } }
-\cs_generate_variant:Nn \__chemmacros_reaction_heading:n { V }
-
-\cs_new_protected:Npn \listofreactions
-  {
-    \__chemmacros_reaction_heading:V \reactionlistname
-    \@starttoc { lor }
-  }
-
-\cs_new_protected:Npn \l@reaction #1#2
-  { \@dottedtocline { 1 } { 1.5em } { 2.3em } { #1 } { #2 } }
-
-% create tagform
-\newtagform { reaction } { \{ } { \} }
-\newcounter { chemmacros_save_reaction }
-\newcounter { reaction }
-
-% switch to reaction tags
-\cs_new_protected:Npn \__chemmacros_begin_reaction:
-  {
-    % create individual names for `hyperref':
-    \bool_if:NT \l__chemmacros_hyperref_bool
-      {
-        \cs_set:Npn \theHequation
-          { R . \theHsection . \arabic { reaction } }
-      }
-    % enable labelformat `reaction':
-    \bool_if:NT \l__chemmacros_varioref_bool
-      { \cs_set_eq:NN \p@equation \p@reaction }
-    \setcounter { chemmacros_save_reaction } { \value { equation } }
-    \setcounter { equation } { \value { reaction } }
-    \usetagform { reaction }
-  }
-
-% switch back to equation tags
-\cs_new_protected:Npn \__chemmacros_end_reaction:
-  {
-    \setcounter { reaction } { \value { equation } }
-    \setcounter { equation } { \value { chemmacros_save_reaction } }
-  }
-
-% --------------------------------------------------------------------------- %
-\bool_new:N \l__chemmacros_reactions_star_bool
-\bool_new:N \l__chemmacros_reactions_args_bool
-
-\keys_define:nn { chemmacros / reaction }
-  {
-    star         .bool_set:N = \l__chemmacros_reactions_star_bool ,
-    star         .default:n  = true ,
-    arg          .bool_set:N = \l__chemmacros_reactions_args_bool ,
-    arg          .default:n  = true ,
-    list-name    .tl_set:N   = \reactionlistname ,
-    list-entry   .code:n     =
-      \tl_set:Nn \l__chemmacros_reaction_lorname_tl { #1 } ,
-    list-heading .tl_set:N   = \l__chemmacros_reaction_heading_tl
-  }
-
-% \DeclareChemReaction[<keyval>]{<name>}{<type>}
-\cs_new_protected:Npn \__chemmacros_define_reaction:Nnnn #1#2#3#4
-  {
-    \bool_set_false:N \l__chemmacros_reactions_star_bool
-    \bool_set_false:N \l__chemmacros_reactions_args_bool
-    \keys_set:nn { chemmacros / reaction } { #2 }
-    \bool_if:NTF \l__chemmacros_reactions_args_bool
-      {
-        #1 { #3 } [ 2 ] []
-          {
-            \__chemmacros_begin_reaction:
-            \AddRxnDesc { ##1 }
-            \begin { #4 } { ##2 }
-              \chemmacros_equation_chemformula:V \BODY
-            \end{ #4 }
-            \__chemmacros_end_reaction:
-          }
-        \bool_if:NT \l__chemmacros_reactions_star_bool
-          {
-            #1 { #3* } [ 1 ]
-              {
-                \begin { #4* } { ##1 }
-                  \chemmacros_equation_chemformula:V \BODY
-                \end { #4* }
-              }
-          }
-      }
-      {
-        #1 { #3 } [ 1 ] []
-          {
-            \__chemmacros_begin_reaction:
-            \AddRxnDesc { ##1 }
-            \begin { #4 }
-              \chemmacros_equation_chemformula:V \BODY
-            \end { #4 }
-            \__chemmacros_end_reaction:
-          }
-        \bool_if:NT \l__chemmacros_reactions_star_bool
-          {
-            #1 { #3* }
-              {
-                \begin { #4* }
-                  \chemmacros_equation_chemformula:V \BODY
-                \end { #4* }
-              }
-          }
-      }
-    \ignorespaces
-  }
-
-\cs_new_protected:Npn \chemmacros_define_reaction:nnn #1#2#3
-  {
-    \cs_if_exist:cTF { #2 }
-      { \__chemmacros_define_reaction:Nnnn \RenewEnviron { #1 } { #2 } { #3 } }
-      { \__chemmacros_define_reaction:Nnnn \NewEnviron { #1 } { #2 } { #3 } }
-  }
-
-\cs_new_protected:Npn \chemmacros_new_reaction:nnn #1#2#3
-  {
-    \cs_if_exist:cTF { #2 }
-      { \msg_error:nnx { chemmacros } { already-defined } { #2 } }
-      { \__chemmacros_define_reaction:Nnnn \NewEnviron { #1 } { #2 } { #3 } }
-  }
-
-\cs_new_protected:Npn \chemmacros_renew_reaction:nnn #1#2#3
-  {
-    \cs_if_exist:cTF { #2 }
-      { \__chemmacros_define_reaction:Nnnn \RenewEnviron { #1 } { #2 } { #3 } }
-      { \msg_error:nnx { chemmacros } { not-defined } { #2 } }
-  }
-
-\NewDocumentCommand \NewChemReaction { O{} m m }
-  { \chemmacros_new_reaction:nnn { #1 } { #2 } { #3 } }
-\NewDocumentCommand \RenewChemReaction { O{} m m }
-  { \chemmacros_renew_reaction:nnn { #1 } { #2 } { #3 } }
-\NewDocumentCommand \DeclareChemReaction { O{} m m }
-  { \chemmacros_declare_reaction:nnn { #1 } { #2 } { #3 } }
-\DeclareChemDeprecated \newreaction \NewChemReaction
-
-\cs_new_protected:Npn \chemmacros_equation_chemformula:n #1
-  { \chemformula_ch:nn { } { #1 } }
-\cs_generate_variant:Nn \chemmacros_equation_chemformula:n { V }
-
-% predefined:
-\NewChemReaction [ star ] { reaction }  { equation }
-\NewChemReaction [ star ] { reactions } { align }
-
-% --------------------------------------------------------------------------
-% thermodynamics et.al.
-% \standardstate as defined by the chemstyle package. Thanks to Joseph Wright
-% the `chemstyle' provides it with \providecommand so it doesn't matter which
-% package defines it first
-\ProvideDocumentCommand \standardstate {}
-  { { \ensuremath { \chemmacros_standardstate: } } }
-
-\cs_new_protected:Npn \chemmacros_standardstate:
-  { \mathpalette \chemmacros_standardstate_aux: \circ }
-
-\cs_new_protected:Npn \chemmacros_standardstate_aux: #1#2
-  {
-    \ooalign
-      {
-        \tex_hfil:D
-        \c_math_toggle_token #1- \c_math_toggle_token
-        \tex_hfil:D
-        \tex_cr:D
-        \tex_hfil:D
-        \c_math_toggle_token #1#2 \c_math_toggle_token
-        \tex_hfil:D
-        \tex_cr:D
-      }
-  }
-
-\cs_new_protected:Npn \changestate
-  { \mathop{} \! \chemDelta }
-
-% --------------------------------------------------------------------------
-% \State
-\tl_new:N  \l__chemmacros_State_delta_tl
-\tl_set:Nn \l__chemmacros_State_delta_tl { \changestate }
-\tl_new:N  \l__chemmacros_State_exponent_tl
-\tl_set:Nn \l__chemmacros_State_exponent_tl { \standardstate }
-
-\bool_new:N      \l__chemmacros_State_delta_bool
-\bool_set_true:N \l__chemmacros_State_delta_bool
-\bool_new:N      \l__chemmacros_State_subscript_left_bool
-\bool_set_true:N \l__chemmacros_State_subscript_left_bool
-\bool_new:N      \l__chemmacros_State_exponent_bool
-\bool_set_true:N \l__chemmacros_State_exponent_bool
-
-\keys_define:nn { chemmacros / state }
-  {
-    delta     .code:n     =
-      {
-        \exp_args:Nf \tl_if_eq:nnTF { #1 } { false }
-          { \bool_set_false:N \l__chemmacros_State_delta_bool }
-          {
-            \bool_set_true:N \l__chemmacros_State_delta_bool
-            \tl_set:Nn \l__chemmacros_State_delta_tl { #1 }
-          }
-      } ,
-    subscript-left .bool_set:N = \l__chemmacros_State_subscript_left_bool ,
-    subscript-left .default:n  = true ,
-    exponent  .code:n     =
-      {
-        \exp_args:Nf \tl_if_eq:nnTF { #1 } { false }
-          { \bool_set_false:N \l__chemmacros_State_exponent_bool }
-          {
-            \bool_set_true:N \l__chemmacros_State_exponent_bool
-            \tl_set:Nn \l__chemmacros_State_exponent_tl { #1 }
-          }
-      } ,
-    exponent  .default:n  = \standardstate
-  }
-
-% old syntax (v1.1):
-% \State[<exp>,<Delta>,<subscript pos>]{<Symbol>}{<subscript>}
-% old syntax (v2.0):
-% \State[<keyval>]{<Symbol>}{<subscript>}
-% {<subscript>} is an optional argument!
-\cs_new_protected:Npn \chemmacros_state:nnn #1#2#3
-  {
-    \group_begin:
-      \keys_set:nn { chemmacros / state } { #1 }
-      \ensuremath
-       {
-          \bool_if:NT \l__chemmacros_State_delta_bool
-            { \tl_use:N \l__chemmacros_State_delta_tl }
-          \bool_if:NT \l__chemmacros_State_subscript_left_bool
-            { \c_math_subscript_token { \text { #3 } } }
-          #2
-          \bool_if:NF \l__chemmacros_State_subscript_left_bool
-            { \c_math_subscript_token { \text { #3 } } }
-          \bool_if:NT \l__chemmacros_State_exponent_bool
-            { ^ { \tl_use:N \l__chemmacros_State_exponent_tl } }
-        }
-    \group_end:
-  }
-\cs_generate_variant:Nn \chemmacros_state:nnn { xnV }
-
-\NewDocumentCommand \State { s O{} m G{} }
-  {
-    \group_begin:
-      \IfBooleanT { #1 }
-        {
-          \keys_set:nn { chemmacros / state }
-            { subscript-left = false , exponent = }
-        }
-      \chemmacros_state:nnn { #2 } { #3 } { #4 }
-    \group_end:
-  }
-
-% --------------------------------------------------------------------------
-\tl_new:N  \l__chemmacros_thermod_subscript_left_tl
-\tl_new:N  \l__chemmacros_thermod_subscript_left_default_tl
-\tl_new:N  \l__chemmacros_thermod_subscript_tl
-\tl_new:N  \l__chemmacros_thermod_subscript_default_tl
-\tl_new:N  \l__chemmacros_thermod_unit_tl
-\tl_new:N  \l__chemmacros_thermod_exponent_tl
-\tl_new:N  \l__chemmacros_thermod_exponent_default_tl
-\tl_set:Nn \l__chemmacros_thermod_exponent_default_tl { \standardstate }
-\tl_new:N  \l__chemmacros_thermod_delta_tl
-\tl_new:N  \l__chemmacros_thermod_delta_default_tl
-\tl_set:Nn \l__chemmacros_thermod_delta_default_tl { \changestate }
-
-\bool_new:N \l__chemmacros_renewstate_bool
-\bool_new:N \l__chemmacros_state_overwrite_error_bool
-
-\keys_define:nn { chemmacros }
-  {
-    State / subscript         .choice: ,
-    State / subscript / left  .code:n   =
-      { \tl_set:Nn \l__chemmacros_thermod_subscript_left_tl { true } } ,
-    State / subscript / right .code:n   =
-      { \tl_set:Nn \l__chemmacros_thermod_subscript_left_tl { false } } ,
-    State / exponent          .tl_set:N =
-      \l__chemmacros_thermod_exponent_tl ,
-    State / delta             .tl_set:N =
-      \l__chemmacros_thermod_delta_tl ,
-    State / unit              .tl_set:N =
-      \l__chemmacros_thermod_unit_tl ,
-    setnewstate / subscript-left .tl_set:N =
-      \l__chemmacros_thermod_subscript_left_default_tl ,
-    setnewstate / subscript   .tl_set:N =
-      \l__chemmacros_thermod_subscript_default_tl ,
-    setnewstate / exponent    .tl_set:N =
-      \l__chemmacros_thermod_exponent_default_tl ,
-    setnewstate / delta       .tl_set:N =
-      \l__chemmacros_thermod_delta_default_tl
-  }
-
-% \NewChemState{<name>}[<keyval>]{<symbol>}{<unit>}
-\NewDocumentCommand \NewChemState { omO{}mm }
-  {
-    \bool_set_false:N \l__chemmacros_renewstate_bool
-    \bool_set_true:N \l__chemmacros_state_overwrite_error_bool
-    \__chemmacros_setnewstate_reset:
-    \IfNoValueTF { #1 }
-      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
-      {
-        \msg_warning:nn { chemmacros } { state-syntax }
-        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
-      }
-  }
-% \DeclareChemState{<name>}[<keyval>]{<symbol>}{<unit>}
-\NewDocumentCommand \DeclareChemState { omO{}mm }
-  {
-    \bool_set_false:N \l__chemmacros_renewstate_bool
-    \bool_set_false:N \l__chemmacros_state_overwrite_error_bool
-    \__chemmacros_setnewstate_reset:
-    \IfNoValueTF { #1 }
-      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
-      {
-        \msg_warning:nn { chemmacros } { state-syntax }
-        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
-      }
-  }
-% \RenewChemState{<name>}[<keyval>]{<symbol>}{<unit>}
-\NewDocumentCommand \RenewChemState { omO{}mm }
-  {
-    \bool_set_true:N \l__chemmacros_renewstate_bool
-    \bool_set_true:N \l__chemmacros_state_overwrite_error_bool
-    \__chemmacros_setnewstate_reset:
-    \IfNoValueTF { #1 }
-      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
-      {
-        \msg_warning:nn { chemmacros } { state-syntax }
-        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
-      }
-  }
-% TODO
-\cs_set_protected:Npn \setnewstate
-  {
-    \msg_warning:nnnn { chemmacros } { command-deprecated }
-      { \setnewstate } { \NewChemState }
-    \NewChemState
-  }
-\cs_set_protected:Npn \renewstate
-  {
-    \msg_warning:nnnn { chemmacros } { command-deprecated }
-      { \renewstate } { \RenewChemState }
-    \RenewChemState
-  }
-
-\cs_new_protected:Npn \__chemmacros_setnewstate_reset:
-  {
-    \tl_set:Nn  \l__chemmacros_thermod_subscript_left_default_tl { true }
-    \tl_clear:N \l__chemmacros_thermod_subscript_default_tl
-    \tl_set:Nn  \l__chemmacros_thermod_exponent_default_tl { \standardstate }
-    \tl_set:Nn  \l__chemmacros_thermod_delta_default_tl { \changestate }
-  }
-
-\cs_new_protected:Npn \chemmacros_define_state:nnnn #1#2#3#4
-  {
-    \keys_set:nn { chemmacros / setnewstate } { #1 }
-    \chemmacros_if_is_cs:nTF { #2 }
-      { \__chemmacros_set_state:xnn { \cs_to_str:N #2 } { #3 } { #4 } }
-      {
-        \msg_warning:nn { chemmacros } { state-syntax }
-        \__chemmacros_set_state:nnn { #2 } { #3 } { #4 }
-      }
-  }
-
-\cs_new_protected:Npn \__chemmacros_set_state:nnn #1#2#3
-  {
-    \bool_if:NT \l__chemmacros_state_overwrite_error_bool
-      {
-        \bool_if:NTF \l__chemmacros_renewstate_bool
-          {
-            \cs_if_exist:cF { #1 }
-              { \msg_error:nnx { chemmacros } { nenew-state } { #1 } }
-          }
-          {
-            \cs_if_exist:cT { #1 }
-              { \msg_error:nnx { chemmacros } { new-state } { #1 } }
-          }
-      }
-    \cs_undefine:c { chemmacros_ #1 _reset: }
-    \cs_undefine:c { c__chemmacros_ #1 _subscript_tl }
-    \cs_undefine:c { c__chemmacros_ #1 _exponent_tl }
-    \cs_undefine:c { c__chemmacros_ #1 _delta_tl }
-    \cs_undefine:c { c__chemmacros_ #1 _left_tl }
-    \cs_undefine:c { c__chemmacros_ #1 _unit_tl }
-    \cs_undefine:c { #1 }
-    \cs_undefine:c { #1 _aux_i:n }
-    \cs_undefine:c { #1 _aux_ii:n }
-    \cs_undefine:c { #1 _aux_iii:n }
-    \group_begin:
-      \tl_const:cV
-        { c__chemmacros_ #1 _subscript_tl }
-        \l__chemmacros_thermod_subscript_default_tl
-      \tl_const:cV
-        { c__chemmacros_ #1 _exponent_tl }
-        \l__chemmacros_thermod_exponent_default_tl
-      \tl_const:cV
-        { c__chemmacros_ #1 _delta_tl }
-        \l__chemmacros_thermod_delta_default_tl
-      \tl_const:cV
-        { c__chemmacros_ #1 _left_tl }
-        \l__chemmacros_thermod_subscript_left_default_tl
-      \tl_const:cn
-        { c__chemmacros_ #1 _unit_tl }
-        { #3 }
-      \cs_new_protected:cpn {chemmacros_ #1 _reset: }
-        {
-          \tl_set_eq:Nc
-            \l__chemmacros_thermod_subscript_tl
-            { c__chemmacros_ #1 _subscript_tl }
-          \tl_set_eq:Nc
-            \l__chemmacros_thermod_exponent_tl
-            { c__chemmacros_ #1 _exponent_tl }
-          \tl_set_eq:Nc
-            \l__chemmacros_thermod_delta_tl
-            { c__chemmacros_ #1 _delta_tl }
-          \tl_set_eq:Nc
-            \l__chemmacros_thermod_subscript_left_tl
-            { c__chemmacros_ #1 _left_tl }
-          \tl_set_eq:Nc
-            \l__chemmacros_thermod_unit_tl
-            { c__chemmacros_ #1 _unit_tl }
-        }
-      \cs_new_protected:cpn { #1 }
-        {
-          \use:c {chemmacros_ #1 _reset: }
-          \peek_meaning:NTF [
-            { \tl_use:c { #1 _aux_i:n } }
-            {
-              \peek_meaning:NTF (
-                { \tl_use:c { #1 _aux_ii:n } }
-                { \tl_use:c { #1 _aux_iii:n } }
-            }
-        }
-      \cs_new_protected:cpn { #1 _aux_i:n } [##1]
-        {
-          \keys_set:nn { chemmacros / State } { ##1 }
-          \peek_meaning:NTF (
-            { \tl_use:c { #1 _aux_ii:n } }
-            { \tl_use:c { #1 _aux_iii:n } }
-        }
-      \cs_new_protected:cpn { #1 _aux_ii:n } (##1)
-        {
-          \tl_set:Nn \l__chemmacros_thermod_subscript_tl { ##1 }
-          \tl_use:c { #1 _aux_iii:n }
-        }
-      \cs_new_protected:cpn { #1 _aux_iii:n } ##1
-        {
-          \ensuremath
-            {
-              \tl_if_eq:VnTF
-                \l__chemmacros_thermod_subscript_left_tl { true }
-                {
-                  \chemmacros_state:xnV
-                    {
-                      subscript-left = true ,
-                      exponent       =
-                        { \exp_not:V \l__chemmacros_thermod_exponent_tl } ,
-                      delta          =
-                        { \exp_not:V \l__chemmacros_thermod_delta_tl }
-                    }
-                    { #2 }
-                }
-                {
-                  \chemmacros_state:xnV
-                    {
-                      subscript-left = false ,
-                      exponent       =
-                        { \exp_not:V \l__chemmacros_thermod_exponent_tl } ,
-                      delta          =
-                        { \exp_not:V \l__chemmacros_thermod_delta_tl }
-                    }
-                    { #2 }
-                }
-                \l__chemmacros_thermod_subscript_tl
-                =
-                \exp_args:NnV \SI { ##1 } \l__chemmacros_thermod_unit_tl
-            }
-        }
-    \group_end:
-    \ignorespaces
-  }
-\cs_generate_variant:Nn \__chemmacros_set_state:nnn { x }
-
-% predefined:
-\NewChemState \Enthalpy {H} {\kilo\joule\per\mole}
-\NewChemState \Entropy [ delta=false, subscript-left=false ]
-  {S} {\joule\per\kelvin\per\mole}
-\NewChemState \Gibbs {G} {\kilo\joule\per\mole}
-
-% --------------------------------------------------------------------------
-% Newman projections
-\fp_new:N  \l__chemmacros_newman_rel_angle_fp
-\fp_zero:N \l__chemmacros_newman_rel_angle_fp
-\fp_new:N  \l__chemmacros_newman_tmp_angle_fp
-\fp_new:N  \l__chemmacros_newman_abs_angle_fp
-\fp_zero:N \l__chemmacros_newman_abs_angle_fp
-\fp_new:N  \l__chemmacros_newman_scale_fp
-\fp_set:Nn \l__chemmacros_newman_scale_fp { 1 }
-\fp_new:N  \l__chemmacros_newman_x_fp
-\fp_new:N  \l__chemmacros_newman_y_fp
-
-\tl_new:N \l__chemmacros_newman_tikz_ring_tl
-\tl_new:N \l__chemmacros_newman_tikz_front_tl
-\tl_new:N \l__chemmacros_newman_tikz_back_tl
-
-\bool_new:N \l__chemmacros_newman_tikz_back_bool
-
-\keys_define:nn { chemmacros / newman }
-  {
-    ring       .tl_set:N  = \l__chemmacros_newman_tikz_ring_tl ,
-    atoms      .tl_set:N  = \l__chemmacros_newman_tikz_front_tl ,
-    back-atoms .code:n    =
-      {
-        \bool_set_true:N \l__chemmacros_newman_tikz_back_bool
-        \tl_set:Nn \l__chemmacros_newman_tikz_back_tl { #1 }
-      } ,
-    scale       .fp_set:N  = \l__chemmacros_newman_scale_fp ,
-    scale       .default:n = 1 ,
-    angle       .fp_set:N  = \l__chemmacros_newman_abs_angle_fp ,
-    angle       .default:n = 0
-  }
-
-% \newman[<keyval>](<angle>){<1>,<2>,<3>,<4>,<5>,<6>}
-\NewDocumentCommand \newman { o d() > { \SplitArgument { 5 } { , } } m }
-  {
-    \group_begin:
-      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / newman } { #1 } }
-      \IfNoValueTF { #2 }
-        { \chemmacros_newman_atoms:nnnnnnn {    } #3 }
-        { \chemmacros_newman_atoms:nnnnnnn { #2 } #3 }
-    \group_end:
-  }
-
-% place atoms:
-% #1: angle
-% #2 - #7: atoms
-\cs_new_protected:Npn \chemmacros_newman_atoms:nnnnnnn #1#2#3#4#5#6#7
-  {
-    \tl_if_blank:nTF { #1 }
-      {
-        \fp_set_eq:NN
-          \l__chemmacros_newman_rel_angle_fp
-          \l__chemmacros_newman_abs_angle_fp
-      }
-      { \fp_set:Nn \l__chemmacros_newman_rel_angle_fp { #1 } }
-    \chemmacros_tikz_picture:xn
-      {
-        scale = \fp_to_tl:N \l__chemmacros_newman_scale_fp ,
-        chemmacros_newman_atom_front / .style =
-          {
-            inner~sep=0pt,
-            outer~sep=0pt,
-            \tl_use:N \l__chemmacros_newman_tikz_front_tl
-          },
-        chemmacros_newman_atom_back / .style =
-          {
-            inner~sep=0pt,
-            outer~sep=0pt,
-            \bool_if:NTF \l__chemmacros_newman_tikz_back_bool
-              { \tl_use:N \l__chemmacros_newman_tikz_back_tl }
-              { \tl_use:N \l__chemmacros_newman_tikz_front_tl }
-          }
-      }
-      {
-        \chemmacros_tikz_draw:f
-          { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
-          (0pt,0pt) circle (\fp_to_dim:N \l__chemmacros_newman_scale_fp * 15) ;
-        \chemmacros_newman_back_node:nn
-          { 30 }
-          { \IfNoValueF { #6 } { #6 } }
-        \chemmacros_newman_back_node:nf
-          { 150 }
-          { \IfNoValueF { #7 } { #7 } }
-        \chemmacros_newman_back_node:nf
-          { 270 }
-          { \IfNoValueF { #5 } { #5 } }
-        \chemmacros_newman_front_node:nf
-          { 90 }
-          { \IfNoValueF { #2 } { #2 } }
-        \chemmacros_newman_front_node:nf
-          { 210 }
-          { \IfNoValueF { #3 } { #3 } }
-        \chemmacros_newman_front_node:nf
-          { 330 }
-          { \IfNoValueF { #4 } { #4 } }
-    }
-  }
-
-% provide cartesian coordiantes from polar coordinates
-% #1: fp variable for x
-% #2: fp variable for y
-% #3: angle
-% #4: radius
-\cs_new_protected:Npn \chemmacros_polar_to_cartesian:NNnn #1#2#3#4
-  {
-    \fp_set:Nn #1 { #4 * cos( #3 / 180 * pi ) }% x
-    \fp_set:Nn #2 { #4 * sin( #3 / 180 * pi ) }% y
-  }
-
-% place back nodes
-\cs_new_protected:Npn \chemmacros_newman_back_node:nn #1#2
-  {
-    \group_begin:
-      \fp_add:Nn \l__chemmacros_newman_rel_angle_fp { #1 }
-      \chemmacros_polar_to_cartesian:NNnn
-        \l__chemmacros_newman_x_fp
-        \l__chemmacros_newman_y_fp
-        { \l__chemmacros_newman_rel_angle_fp }
-        { \l__chemmacros_newman_scale_fp }
-      \chemmacros_tikz_draw:f
-        { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
-        (
-          15 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
-          15 * \fp_to_dim:N \l__chemmacros_newman_y_fp
-        )
-        --
-        (
-          30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
-          30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
-        ) ;
-      \chemmacros_polar_to_cartesian:NNnn
-        \l__chemmacros_newman_x_fp
-        \l__chemmacros_newman_y_fp
-        { \l__chemmacros_newman_rel_angle_fp }
-        { \l__chemmacros_newman_scale_fp }
-      \chemmacros_tikz_node:f
-        {
-          chemmacros_newman_atom_back,
-          anchor = -180 + \fp_to_int:N \l__chemmacros_newman_rel_angle_fp
-        }
-        at
-        (
-          31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
-          31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
-        )
-        { #2 } ;
-    \group_end:
-  }
-\cs_generate_variant:Nn \chemmacros_newman_back_node:nn { nf }
-
-% place front nodes:
-\cs_new_protected:Npn \chemmacros_newman_front_node:nn #1#2
-  {
-    \chemmacros_polar_to_cartesian:NNnn
-      \l__chemmacros_newman_x_fp
-      \l__chemmacros_newman_y_fp
-      { #1 }
-      { \l__chemmacros_newman_scale_fp }
-    \chemmacros_tikz_draw:f
-      { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
-      (0pt,0pt) -- ++
-      (
-        30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
-        30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
-      ) ;
-    \chemmacros_polar_to_cartesian:NNnn
-      \l__chemmacros_newman_x_fp
-      \l__chemmacros_newman_y_fp
-      { #1 }
-      { \l__chemmacros_newman_scale_fp }
-    \chemmacros_tikz_node:f
-      { chemmacros_newman_atom_front, anchor = -180 + #1 }
-      at
-      (
-        31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
-        31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
-      )
-      { #2 } ;
-  }
-\cs_generate_variant:Nn \chemmacros_newman_front_node:nn { nf }
-
-% --------------------------------------------------------------------------
-% \orbital[<keyval>]{<type>}
-% variables:
-\bool_new:N      \l__chemmacros_orbital_type_s_bool
-\bool_new:N      \l__chemmacros_orbital_type_p_bool
-\bool_new:N      \l__chemmacros_orbital_type_sp_bool
-\bool_new:N      \l__chemmacros_orbital_type_sptwo_bool
-\bool_new:N      \l__chemmacros_orbital_type_spthree_bool
-\bool_new:N      \l__chemmacros_orbital_s_phase_bool
-\bool_set_true:N \l__chemmacros_orbital_s_phase_bool
-\bool_new:N      \l__chemmacros_orbital_p_phase_bool
-\bool_set_true:N \l__chemmacros_orbital_p_phase_bool
-\bool_new:N      \l__chemmacros_orbital_sp_phase_bool
-\bool_set_true:N \l__chemmacros_orbital_sp_phase_bool
-\bool_new:N      \l__chemmacros_orbital_sptwo_phase_bool
-\bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool
-\bool_new:N      \l__chemmacros_orbital_spthree_phase_bool
-\bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool
-\bool_new:N      \l__chemmacros_orbital_p_half_bool
-\bool_new:N      \l__chemmacros_orbital_overlay_bool
-\bool_new:N      \l__chemmacros_orbital_opacity_bool
-
-\tl_new:N  \l__chemmacros_orbital_s_color_tl
-\tl_set:Nn \l__chemmacros_orbital_s_color_tl { black }
-\tl_new:N  \l__chemmacros_orbital_s_phase_color_tl
-\tl_new:N  \l__chemmacros_orbital_p_color_tl
-\tl_set:Nn \l__chemmacros_orbital_p_color_tl { black }
-\tl_new:N  \l__chemmacros_orbital_p_pphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_p_mphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_sp_color_tl
-\tl_set:Nn \l__chemmacros_orbital_sp_color_tl { black }
-\tl_new:N  \l__chemmacros_orbital_sp_pphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_sp_mphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_sptwo_color_tl
-\tl_set:Nn \l__chemmacros_orbital_sptwo_color_tl { black }
-\tl_new:N  \l__chemmacros_orbital_sptwo_pphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_sptwo_mphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_spthree_color_tl
-\tl_set:Nn \l__chemmacros_orbital_spthree_color_tl { black }
-\tl_new:N  \l__chemmacros_orbital_spthree_pphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_spthree_mphase_color_tl
-\tl_new:N  \l__chemmacros_orbital_s_scale_tl
-\tl_set:Nn \l__chemmacros_orbital_s_scale_tl { 1 }
-\tl_new:N  \l__chemmacros_orbital_p_scale_tl
-\tl_set:Nn \l__chemmacros_orbital_p_scale_tl { 1 }
-\tl_new:N  \l__chemmacros_orbital_sp_scale_tl
-\tl_set:Nn \l__chemmacros_orbital_sp_scale_tl { 1 }
-\tl_new:N  \l__chemmacros_orbital_sptwo_scale_tl
-\tl_set:Nn \l__chemmacros_orbital_sptwo_scale_tl { 1 }
-\tl_new:N  \l__chemmacros_orbital_spthree_scale_tl
-\tl_set:Nn \l__chemmacros_orbital_spthree_scale_tl { 1 }
-
-\fp_new:N  \l__chemmacros_orbital_angle_fp
-\fp_set:Nn \l__chemmacros_orbital_angle_fp { 90 }
-\fp_new:N  \l__chemmacros_orbital_opacity_fp
-\fp_set:Nn \l__chemmacros_orbital_opacity_fp { 0.5 }
-
-\cs_new:Npn \__chemmacros_orbital_options:
-  {
-    \__chemmacros_orbital_overlay: , \__chemmacros_orbital_opacity: ,
-    inner~sep=0 , outer~sep=0 , line~width=.2pt ,
-    rotate = { \fp_use:N \l__chemmacros_orbital_angle_fp - 90 } ,
-    baseline ,
-    minimum~size = 0
-  }
-
-\cs_new:Npn \__chemmacros_orbital_overlay:
-  { \bool_if:NT \l__chemmacros_orbital_overlay_bool { overlay } }
-
-\cs_new:Npn \__chemmacros_orbital_opacity:
-  {
-    \bool_if:NT \l__chemmacros_orbital_opacity_bool
-      { opacity = { \fp_use:N \l__chemmacros_orbital_opacity_fp } }
-  }
-
-% --------------------------------------------------------------------------
-% s-orbitals
-\cs_new_protected:Npn \__chemmacros_orbital_type_s:
-  {
-    \bool_set_true:N \l__chemmacros_orbital_type_s_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
-  }
-
-\keys_define:nn { chemmacros / orbital / s }
-  {
-    phase .choice: ,
-    phase / + .code:n =
-      { \bool_set_true:N \l__chemmacros_orbital_s_phase_bool } ,
-    phase / - .code:n =
-      { \bool_set_false:N \l__chemmacros_orbital_s_phase_bool } ,
-    scale .tl_set:N   = \l__chemmacros_orbital_s_scale_tl ,
-    color .tl_set:N   = \l__chemmacros_orbital_s_color_tl
-  }
-
-\cs_new_protected:Npn \__chemmacros_orbital_s_draw:n #1
-  {
-    \keys_set:nn { chemmacros / orbital / s } { #1 }
-    \bool_if:NTF \l__chemmacros_orbital_s_phase_bool
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_s_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_s_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_s_color_tl ! 90 }
-          }
-      }
-      {
-        \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
-          { black ! 5 }
-      }
-    \chemmacros_tikz_picture:xn{ \__chemmacros_orbital_options: }
-      {
-        \chemmacros_tikz_shade:f
-          { ball~color = \l__chemmacros_orbital_s_phase_color_tl }
-          (0pt,0pt) circle (\l__chemmacros_orbital_s_scale_tl * .6em) ;
-      }
-  }
-
-% --------------------------------------------------------------------------
-% p-orbitals
-\cs_new_protected:Npn \__chemmacros_orbital_type_p:
-  {
-    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
-    \bool_set_true:N  \l__chemmacros_orbital_type_p_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
-  }
-
-\keys_define:nn { chemmacros / orbital / p }
-  {
-    phase .choice: ,
-    phase / + .code:n =
-      { \bool_set_true:N \l__chemmacros_orbital_p_phase_bool } ,
-    phase / - .code:n =
-      { \bool_set_false:N \l__chemmacros_orbital_p_phase_bool } ,
-    scale .tl_set:N   = \l__chemmacros_orbital_p_scale_tl ,
-    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
-    color .tl_set:N   = \l__chemmacros_orbital_p_color_tl ,
-    half  .bool_set:N = \l__chemmacros_orbital_p_half_bool ,
-    half  .default:n  = true
-  }
-
-\cs_new_protected:Npn \__chemmacros_orbital_p_draw:n #1
-  {
-    \keys_set:nn { chemmacros / orbital / p } { #1 }
-    \bool_if:NTF \l__chemmacros_orbital_p_phase_bool
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
-          { black ! 5 }
-        
-      }
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
-          { black ! 5 }
-      }
-    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
-      {
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_p_pphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_p_pphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_p_scale_tl * 2em ,
-            \l__chemmacros_orbital_p_scale_tl * 2em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_p_scale_tl * 2em ,
-            \l__chemmacros_orbital_p_scale_tl * 2em
-          )
-          .. (0pt,0pt);
-        \bool_if:NF \l__chemmacros_orbital_p_half_bool
-          {
-            \chemmacros_tikz_shadedraw:f
-              {
-                draw = \l__chemmacros_orbital_p_mphase_color_tl ,
-                ball~color = \l__chemmacros_orbital_p_mphase_color_tl
-              }
-              (0pt,0pt) .. controls ++
-              (
-                - \l__chemmacros_orbital_p_scale_tl * 2em ,
-                - \l__chemmacros_orbital_p_scale_tl * 2em
-              )
-              and ++
-              (
-                \l__chemmacros_orbital_p_scale_tl * 2em ,
-                - \l__chemmacros_orbital_p_scale_tl * 2em
-              )
-              .. (0pt,0pt);
-          }
-      }
-  }
-
-% --------------------------------------------------------------------------
-% sp-orbitals
-\cs_new_protected:Npn \__chemmacros_orbital_type_sp:
-  {
-    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
-    \bool_set_true:N  \l__chemmacros_orbital_type_sp_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
-  }
-
-\keys_define:nn { chemmacros / orbital / sp }
-  {
-    phase .choice: ,
-    phase / + .code:n =
-      { \bool_set_true:N \l__chemmacros_orbital_sp_phase_bool } ,
-    phase / - .code:n =
-      { \bool_set_false:N \l__chemmacros_orbital_sp_phase_bool } ,
-    scale .tl_set:N   = \l__chemmacros_orbital_sp_scale_tl ,
-    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
-    color .tl_set:N   = \l__chemmacros_orbital_sp_color_tl
-  }
-
-\cs_new_protected:Npn \__chemmacros_orbital_sp_draw:n #1
-  {
-    \keys_set:nn { chemmacros / orbital / sp } { #1 }
-    \bool_if:NTF \l__chemmacros_orbital_sp_phase_bool
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
-          { black ! 5 }
-        
-      }
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
-          { black ! 5 }
-      }
-    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
-      {
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_sp_pphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_sp_pphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_sp_scale_tl * 2em ,
-            \l__chemmacros_orbital_sp_scale_tl * 2em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_sp_scale_tl * 2em ,
-            \l__chemmacros_orbital_sp_scale_tl * 2em
-          )
-          .. (0pt,0pt);
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_sp_mphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_sp_mphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_sp_scale_tl * .6em ,
-            - \l__chemmacros_orbital_sp_scale_tl * .6em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_sp_scale_tl * .6em ,
-            - \l__chemmacros_orbital_sp_scale_tl * .6em
-          )
-          .. (0pt,0pt);
-      }
-  }
-
-% --------------------------------------------------------------------------
-% sp2-orbitals
-\cs_new_protected:Npn \__chemmacros_orbital_type_sptwo:
-  {
-    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
-    \bool_set_true:N  \l__chemmacros_orbital_type_sptwo_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
-  }
-
-\keys_define:nn { chemmacros / orbital / sp2 }
-  {
-    phase .choice: ,
-    phase / + .code:n =
-      { \bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool } ,
-    phase / - .code:n =
-      { \bool_set_false:N \l__chemmacros_orbital_sptwo_phase_bool } ,
-    scale .tl_set:N   = \l__chemmacros_orbital_sptwo_scale_tl ,
-    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
-    color .tl_set:N   = \l__chemmacros_orbital_sptwo_color_tl
-  }
-
-\cs_new_protected:Npn \__chemmacros_orbital_sptwo_draw:n #1
-  {
-    \keys_set:nn { chemmacros / orbital / sp2 } { #1 }
-    \bool_if:NTF \l__chemmacros_orbital_sptwo_phase_bool
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
-          { black ! 5 }
-        
-      }
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
-          { black ! 5 }
-      }
-    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
-      {
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_sptwo_pphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_sptwo_pphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
-            \l__chemmacros_orbital_sptwo_scale_tl * 2em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
-            \l__chemmacros_orbital_sptwo_scale_tl * 2em
-          )
-          .. (0pt,0pt);
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_sptwo_mphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_sptwo_mphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
-            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
-            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
-          )
-          .. (0pt,0pt);
-      }
-  }
-
-% --------------------------------------------------------------------------
-% sp3-orbitals
-\cs_new_protected:Npn \__chemmacros_orbital_type_spthree:
-  {
-    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
-    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
-    \bool_set_true:N  \l__chemmacros_orbital_type_spthree_bool
-  }
-
-\keys_define:nn { chemmacros / orbital / sp3 }
-  {
-    phase .choice: ,
-    phase / + .code:n =
-      { \bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool } ,
-    phase / - .code:n =
-     { \bool_set_false:N \l__chemmacros_orbital_spthree_phase_bool } ,
-    scale .tl_set:N   = \l__chemmacros_orbital_spthree_scale_tl ,
-    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
-    color .tl_set:N   = \l__chemmacros_orbital_spthree_color_tl
-  }
+\cs_new_protected:Npn \ChemCompatibilityFrom #1#2 \EndChemCompatibility
+  { \chemmacros_if_compatiblity:nnT {>=} {#1} {#2} }
 
-\cs_new_protected:Npn \__chemmacros_orbital_spthree_draw:n #1
-  {
-    \keys_set:nn { chemmacros / orbital / sp3 } { #1 }
-    \bool_if:NTF \l__chemmacros_orbital_spthree_phase_bool
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
-          { black ! 5 }
-        
-      }
-      {
-        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
-          }
-          {
-            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
-              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
-          }
-        \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
-          { black ! 5 }
-      }
-    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
-      {
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_spthree_pphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_spthree_pphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_spthree_scale_tl * 2em ,
-            \l__chemmacros_orbital_spthree_scale_tl * 2em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_spthree_scale_tl * 2em ,
-            \l__chemmacros_orbital_spthree_scale_tl * 2em
-          )
-          .. (0pt,0pt);
-        \chemmacros_tikz_shadedraw:f
-          {
-            draw = \l__chemmacros_orbital_spthree_mphase_color_tl ,
-            ball~color = \l__chemmacros_orbital_spthree_mphase_color_tl
-          }
-          (0pt,0pt) .. controls ++
-          (
-            - \l__chemmacros_orbital_spthree_scale_tl * 1em ,
-            - \l__chemmacros_orbital_spthree_scale_tl * 1em
-          )
-          and ++
-          (
-            \l__chemmacros_orbital_spthree_scale_tl * 1em ,
-            - \l__chemmacros_orbital_spthree_scale_tl * 1em
-          )
-          .. (0pt,0pt);
-      }
-  }
+\cs_new_protected:Npn \ChemCompatibilityTo #1#2 \EndChemCompatibility
+  { \chemmacros_if_compatiblity:nnT {<=} {#1} {#2} }
 
-% --------------------------------------------------------------------------
-% main command
-\keys_define:nn { chemmacros / orbital }
+\cs_new_protected:Npn \ChemCompatibilityBetween #1#2#3 \EndChemCompatibility
   {
-    overlay .bool_set:N = \l__chemmacros_orbital_overlay_bool ,
-    overlay .default:n  = true ,
-    opacity .code:n     =
+    \bool_if:nT
       {
-        \fp_compare:nTF { #1 = 1 }
-          { \bool_set_false:N \l__chemmacros_orbital_opacity_bool }
-          { \bool_set_true:N \l__chemmacros_orbital_opacity_bool }
-        \fp_set:Nn \l__chemmacros_orbital_opacity_fp { #1 }
+        \chemmacros_if_compatiblity_p:nn {>=} {#1} &&
+        \chemmacros_if_compatiblity_p:nn {<=} {#2}
       }
+      {#3}
   }
 
-\keys_define:nn { chemmacros / orbital / type }
-  {
-    s   .code:n = { \__chemmacros_orbital_type_s: } ,
-    p   .code:n = { \__chemmacros_orbital_type_p: } ,
-    sp  .code:n = { \__chemmacros_orbital_type_sp: } ,
-    sp2 .code:n = { \__chemmacros_orbital_type_sptwo: } ,
-    sp3 .code:n = { \__chemmacros_orbital_type_spthree: }
-  }
-
-\cs_new_protected:Npn \chemmacros_orbital:n #1
-  {
-    \bool_if:NT \l__chemmacros_orbital_type_s_bool
-      { \__chemmacros_orbital_s_draw:n { #1 } }
-    \bool_if:NT \l__chemmacros_orbital_type_p_bool
-      { \__chemmacros_orbital_p_draw:n { #1 } }
-    \bool_if:NT \l__chemmacros_orbital_type_sp_bool
-      { \__chemmacros_orbital_sp_draw:n { #1 } }
-    \bool_if:NT \l__chemmacros_orbital_type_sptwo_bool
-      { \__chemmacros_orbital_sptwo_draw:n { #1 } }
-    \bool_if:NT \l__chemmacros_orbital_type_spthree_bool
-      { \__chemmacros_orbital_spthree_draw:n { #1 } }
-  }
-
-\NewDocumentCommand \orbital { o m }
+% let's see that the max number is the newest (=current) version
+\chemmacros_if_compatiblity:nnT {>} { \c_chemmacros_version_number_tl }
   {
-    \group_begin:
-      \keys_set:nn { chemmacros / orbital / type } { #2 }
-      \IfNoValueTF { #1 }
-        { \chemmacros_orbital:n {    } }
-        { \chemmacros_orbital:n { #1 } }
-    \group_end:
+    \fp_set:Nn \l__chemmacros_compatibility_version_fp
+      { \c_chemmacros_version_number_tl }
   }
 
 % --------------------------------------------------------------------------
-% arrow tips for electron movement
-\dim_new:N \l__chemmacros_el_length_dim
-
-% full tip for pairs
-\pgfarrowsdeclare { el } { el }
-  {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
-    \pgfarrowsrightextend { .5\pgflinewidth }
-  }
+% compatibility too low:
+\chemmacros_if_compatiblity:nnT {<} {4.7}
   {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfsetdash {} { 0pt }
-    \pgfsetroundjoin
-    \pgfsetroundcap
-    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
-    \pgfpathlineto
-      {
-        \pgfpoint
-          { -\l__chemmacros_el_length_dim }
-          { .3\l__chemmacros_el_length_dim }
-      }
-    \pgfpathlineto
-      { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
-    \pgfpathlineto
-      {
-        \pgfpoint
-          { -\l__chemmacros_el_length_dim }
-          { -.3\l__chemmacros_el_length_dim }
-      }
-    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
-    \pgfusepathqfillstroke
+    \msg_warning:nnx {chemmacros} {too-low-compatibility}
+      { \fp_to_tl:N \l__chemmacros_compatibility_version_fp }
   }
 
-% half tip on the left
-\pgfarrowsdeclare { left~el } { left~el }
+% not the newest version:
+\chemmacros_if_compatiblity:nnT {<} { \c_chemmacros_version_number_tl }
   {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
-    \pgfarrowsrightextend { .5\pgflinewidth }
+    \msg_warning:nnx {chemmacros} {low-compatibility}
+      { \fp_to_tl:N \l__chemmacros_compatibility_version_fp }
   }
-  {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfsetdash {} { 0pt }
-    \pgfsetroundjoin
-    \pgfsetroundcap
-    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
-    \pgfpathlineto
-      {
-        \pgfpoint
-          { -\l__chemmacros_el_length_dim }
-          { .3\l__chemmacros_el_length_dim }
-      }
-    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
-    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
-    \pgfusepathqfillstroke
-  }
-
-% half tip in the right
-\pgfarrowsdeclare { right~el } { right~el }
-  {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
-    \pgfarrowsrightextend { .5\pgflinewidth }
-  }
-  {
-    \dim_set:Nn \l__chemmacros_el_length_dim
-      { 2.5pt + 2.5\pgflinewidth }
-    \pgfsetdash {} { 0pt }
-    \pgfsetroundjoin
-    \pgfsetroundcap
-    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
-    \pgfpathlineto
-      {
-        \pgfpoint
-          { -\l__chemmacros_el_length_dim }
-          { -.3\l__chemmacros_el_length_dim }
-      }
-    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
-    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
-    \pgfusepathqfillstroke
-  }
-
-% --------------------------------------------------------------------------
-% setup
-\NewDocumentCommand \chemsetup { o m }
-  {
-    \IfNoValueTF { #1 }
-      { \keys_set:nn { chemmacros } { #2 } }
-      {
-        \tl_if_eq:nnTF { #1 } { chemformula }
-          { \setchemformula { #2 } }
-          { \keys_set:nn { chemmacros / #1 } { #2 } }
-      }
-    \ignorespaces
-  }
-
-
+  
 % --------------------------------------------------------------------------
-% hyperref support
-% ?? unsure about adding IUPAC commands
-\AfterPackage* { hyperref }
-  {
-    \pdfstringdefDisableCommands
-      {
-        % \cs_set:Npn \- { - } % maybe not a good idea...
-        \cs_set:Npn \| { }
-        \cs_set:Npn \pH { pH }
-        \cs_set:Npn \pOH { pOH }
-        \cs_set:Npn \iupac #1 { #1 }
-        \cs_set:Npn \cip #1 { (#1) }
-        \cs_set:Npn \cis { cis }
-        \cs_set:Npn \trans { trans }
-        \cs_set:Npn \tert { tert }
-        \cs_set:Npn \ortho { o }
-        \cs_set:Npn \meta { m }
-        \cs_set:Npn \para { p }
-        \cs_set:Npn \syn { syn }
-        \cs_set:Npn \anti { anti }
-      }
-  }
+\chemmacros_if_compatiblity:nnTF {<} {5.0}
+  { \RequirePackage{chemmacros4} }
+  { \RequirePackage{chemmacros5} }
 
 % --------------------------------------------------------------------------
-% language support -- provided through `translations'
-% equilibrium constants:
-\DeclareTranslationFallback {K-acid}  {\mathrm{a}}
-\DeclareTranslation{German} {K-acid}  {\mathrm{s}}
-\DeclareTranslation{Dutch}  {K-acid}  {\mathrm{z}}
-
-\DeclareTranslationFallback {K-base}  {\mathrm{b}}
-
-\DeclareTranslationFallback {K-water} {\mathrm{w}}
-
-% phases:
-\DeclareTranslation{German}{phase-sld}{ f }
-\DeclareTranslation{German}{phase-lqd}{ f{}l }
-% list of reactions:
-\DeclareTranslationFallback  {list-of-reactions} { List~ of~ reactions }
-\DeclareTranslation{English} {list-of-reactions} { List~ of~ reactions }
-\DeclareTranslation{German}  {list-of-reactions} { Reaktionsverzeichnis }
-\DeclareTranslation{Italian} {list-of-reactions} { Elenco~ delle~ reazioni }
-\DeclareTranslation{French}  {list-of-reactions} { Table~ des~ r\'eactions }
-\DeclareTranslation{Dutch}   {list-of-reactions} { Lijst~ van~ reacties }
-%
-\DeclareTranslationFallback  {reaction} { Reaction }
-\DeclareTranslation{English} {reaction} { Reaction }
-\DeclareTranslation{German}  {reaction} { Reaktion }
-\DeclareTranslation{Italian} {reaction} { Reazione }
-\DeclareTranslation{French}  {reaction} { R\'eaction }
-\DeclareTranslation{Dutch}   {reaction} { Reactie }
-
-\tl_set:Nn \l__chemmacros_reaction_lorname_tl
-  { \chemmacros_translate:n {reaction} }
-\tl_set:Nn \reactionlistname
-  { \chemmacros_translate:n {list-of-reactions} }
-
 \tex_endinput:D
 
 % --------------------------------------------------------------------------
@@ -4284,7 +357,7 @@ Version history
                             the new package in the family: `chemgreek'
                           - \OX and \redox now work in `amsmath's environment
                             by ignoring the measuring phase
-                          - language management with the halp of the
+                          - language management with the help of the
                             `translations' package =>
                             recognize document language automatically and use
                             it if it a) is known to `chemmacros' and b) has
@@ -4374,10 +447,13 @@ Version history
                           - allow \NewChemPhase and friends after \begin{document}
                           - new optional argument to phase commands
                           - new options `nmr/method' and `nmr/connector'
-
-% --------------------------------------------------------------------------- %
-% TODO:
-- add d-orbitals
-- make electron movement arrow tips (`el', `left el' and `right el') public
-- phase commands with arguments (see http://texwelt.de/wissen/fragen/9264)
-
+2015/09/11 - version 5.0  - the former chemmacros.sty is now chemmacros4.sty
+                            and can be loaded through the `compatibility'
+                            option
+                          - chemmacros is now organized in separate modules
+                            which either are preloaded or can be loaded by the
+                            user with \usechemmodule
+                          - various changes, see
+                            http://www.mychemistry.eu/2015/06/chemmacros-development/
+                            and the manual section 3.4. Upgrading from version < 5.0
+                            for details
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros4.sty b/Master/texmf-dist/tex/latex/chemmacros/chemmacros4.sty
new file mode 100644
index 00000000000..d1316031749
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros4.sty
@@ -0,0 +1,4100 @@
+% --------------------------------------------------------------------------
+% the CHEMMACROS package
+%
+%   comprehensive support for typesetting chemistry documents
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+\RequirePackage{ expl3 , xparse , l3keys2e }
+\def\chemmacros@version{4.7a}
+\def\chemmacros@date{2015/08/16}
+
+\ExplSyntaxOn
+\ProvidesExplPackage
+  {chemmacros4}
+  {\chemmacros@date}
+  {\chemmacros@version}
+  {\c_chemmacros_info_tl \c_space_tl (CN)}
+
+% --------------------------------------------------------------------------
+% variants of kernel commands:
+\cs_generate_variant:Nn \prop_if_in:NnTF   { NV , Nx }
+\cs_generate_variant:Nn \prop_put:Nnn      { NV , NVV , NVx }
+\cs_generate_variant:Nn \prop_get:NnNTF    { NV }
+\cs_generate_variant:Nn \tl_set_rescan:Nnn { NnV }
+\cs_generate_variant:Nn \tl_if_eq:nnTF     { V }
+\cs_generate_variant:Nn \tl_const:cn       { cV }
+
+% --------------------------------------------------------------------------
+% load required packages
+% the technical ones:
+\RequirePackage { environ , scrlfile , etoolbox , translations }
+% related to other topics like mathematics or graphics:
+\RequirePackage { xfrac , siunitx , tikz, mathtools , bm }
+% other packages of this bundle -- ghsystem is not loaded here but at the end
+% of the preamble depending on a package option:
+\RequirePackage { chemformula , chemgreek }
+% TikZ libraries (the don't like expl3 syntax):
+\ExplSyntaxOff
+\usetikzlibrary{calc,arrows}
+\ExplSyntaxOn
+
+% --------------------------------------------------------------------------
+% boolean variables for the package options
+\bool_new:N      \l__chemmacros_xspace_bool
+\bool_set_true:N \l__chemmacros_xspace_bool
+
+\bool_new:N      \l__chemmacros_circled_bool
+\bool_set_true:N \l__chemmacros_circled_bool
+\bool_new:N      \l__chemmacros_circled_formal_bool
+\bool_set_true:N \l__chemmacros_circled_formal_bool
+\bool_new:N      \l__chemmacros_circled_chem_bool
+\bool_set_true:N \l__chemmacros_circled_chem_bool
+
+\bool_new:N      \l__chemmacros_EZ_cool_bool
+\bool_new:N      \l__chemmacros_Nu_mathspec_bool
+\bool_new:N      \l__chemmacros_chemstyle_bool
+\bool_new:N      \l__chemmacros_hyperref_bool
+\bool_new:N      \l__chemmacros_varioref_bool
+\bool_new:N      \l__chemmacros_chemfig_bool
+\bool_new:N      \l__chemmacros_ghsystem_bool
+% \bool_set_true:N \l__chemmacros_ghsystem_bool
+
+\bool_new:N      \l__chemmacros_iupac_restricted_bool
+\bool_new:N      \l__chemmacros_iupac_strict_bool
+\bool_new:N      \l__chemmacros_in_document_bool
+
+\AtBeginDocument
+  {
+    \bool_set_true:N \l__chemmacros_in_document_bool
+    \@ifpackageloaded { chemstyle }
+      { \bool_set_true:N \l__chemmacros_chemstyle_bool }
+      { \bool_set_false:N \l__chemmacros_chemstyle_bool }
+    \@ifpackageloaded { varioref }
+      { \bool_set_true:N \l__chemmacros_varioref_bool }
+      { \bool_set_false:N \l__chemmacros_varioref_bool }
+    \@ifpackageloaded { hyperref }
+      { \bool_set_true:N \l__chemmacros_hyperref_bool }
+      { \bool_set_false:N \l__chemmacros_hyperref_bool }
+    \@ifpackageloaded { chemfig }
+      { \bool_set_true:N \l__chemmacros_chemfig_bool }
+      { \bool_set_false:N \l__chemmacros_chemfig_bool }
+  }
+
+% --------------------------------------------------------------------------
+% warning / error messages
+\msg_new:nnnn { chemmacros } { language-not-defined }
+  { The~ language~ `#1'~ is~ not~ defined~ by~ chemmacros. }
+  {
+    You~ chose~ the~ language~ `#1'~ which~ is~ not~ defined~ by~ chemmacros.~
+    `english'~ is~ used~ instead.~ If~ you~ just~ mistyped~ try~ again!~
+    Otherwise~ contact~ the~ author~ and~ he'll~ probably~ add~ your~ language.
+  }
+
+\msg_new:nnnn { chemmacros } { already-defined }
+  { The~ command~ #1~ is~ already~ defined. }
+  {
+    The~ command~ #1~ has~ already~ been~ otherwise.~ chemmacros~ also~ tries~
+    to~ define~ it~ and~ fails.~
+  }
+
+\msg_new:nnnn { chemmacros } { not-defined }
+  { The~ command~ #1~ is~ not~ defined,~ yet. }
+  {
+    The~ command~ #1~ is~ not~ defined,~ yet.~ chemmacros~ tries~ to~
+    redefine~ it~ and~ fails.~
+  }
+
+\msg_new:nnnn { chemmacros } { option-deprecated }
+  { The~ option~ `#1'~ is~ deprecated.~ I~ will~ ignore~ it. }
+  {
+    The~ package~ option~ `#1'~ is~ deprecated~ and~ not~ used~ by~
+    chemmacros~ any~ more.~ It~ will~ therefore~ simply~ be~ ignored.
+  }
+
+\msg_new:nnnn { chemmacros } { command-deprecated }
+  {
+    The~ command~ \token_to_str:N #1 \c_space_tl is~ deprecated.~ Use~
+    \token_to_str:N #2 \c_space_tl instead.
+  }
+  {
+    The~ command~ \token_to_str:N #1 \c_space_tl is~ deprecated.~ Use~
+    \token_to_str:N #2 \c_space_tl instead.
+  }
+
+\msg_new:nnnn { chemmacros } { command-dropped }
+  {
+    The~ command~ \token_to_str:N #1 \c_space_tl has~ been~ dropped.~ I'm~
+    sorry.
+  }
+  {
+    The~ command~ \token_to_str:N #1 \c_space_tl has~ been~ dropped.~ I'm~
+    sorry.
+  }
+
+\msg_new:nnnn { chemmacros } { new-particle }
+  {
+    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
+    defined.
+  }
+  {
+    You've~ tried~ to~ define~ a~ particle~ with~ \token_to_str:N
+    \NewChemParticle ,~ but~ the~ command~ sequence~ \token_to_str:N #1
+    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+  }
+
+\msg_new:nnnn { chemmacros } { renew-particle }
+  { The~ particle~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
+  {
+    You've~ tried~ to~ renew~ the~ particle~ \token_to_str:N #1 ,~ but~ it~
+    doesn't~ exist.
+  }
+
+\msg_new:nnnn { chemmacros } { new-latin }
+  {
+    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
+    defined.
+  }
+  {
+    You've~ tried~ to~ define~ a~ latin~ phrase~ with~\token_to_str:N
+    \NewChemLatin ,~ but~ the~ command~ sequence~ \token_to_str:N #1
+    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+  }
+
+\msg_new:nnnn { chemmacros } { renew-latin }
+  { The~ latin~ phrase \token_to_str:N #1 \c_space_tl is~ not~ defined. }
+  {
+    You've~ tried~ to~ renew~ the~ latin~ phrase~ \token_to_str:N #1 ,~ but~
+    it~ doesn't~ exist.
+  }
+
+\msg_new:nnnn { chemmacros } { new-nmr }
+  {
+    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
+    defined.
+  }
+  {
+    You've~ tried~ to~ define~ a~ NMR~ command~ with~\token_to_str:N
+    \NewChemParticle ,~ but~ the~ command~ sequence~ \token_to_str:N #1
+    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+  }
+
+\msg_new:nnnn { chemmacros } { renew-nmr }
+  { The~ NMR~ command~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
+  {
+    You've~ tried~ to~ renew~ the~ NMR~ command~ \token_to_str:N #1 ,~ but~
+    it~ doesn't~ exist.
+  }
+
+\msg_new:nnnn { chemmacros } { new-phase }
+  {
+    The~ command~ sequence~ \token_to_str:N #1 \c_space_tl is~ already~
+    defined.
+  }
+  {
+    You've~ tried~ to~ define~ a~ phase~ with~ \token_to_str:N
+    \NewChemPhase ,~ but~ the~ command~ sequence~ \token_to_str:N #1
+    \c_space_tl already~ exists.~ Please~ choose~ another~ name.
+  }
+
+\msg_new:nnnn { chemmacros } { renew-phase }
+  { The~ phase~ \token_to_str:N #1 \c_space_tl is~ not~ defined. }
+  {
+    You've~ tried~ to~ renew~ the~ phase~ \token_to_str:N #1 ,~ but~ it~
+    doesn't~ exist.
+  }
+
+\msg_new:nnnn { chemmacros } { new-iupac }
+  {
+    The~ iupac~ naming~ command~ \token_to_str:N #1 \c_space_tl is~ already~
+    defined.
+  }
+  {
+    You've~ tried~ to~ define~ a~ iupac~ naming~ command~ with~
+    \token_to_str:N \NewChemIUPAC ,~ but~ the~ iupac~ command~
+    \token_to_str:N #1 \c_space_tl already~ exists.~ Choose~ another~ name~
+    or~ use~ \token_to_str:N \RenewChemIUPAC .
+  }
+
+\msg_new:nnnn { chemmacros } { renew-iupac }
+  {
+    The~ iupac~ naming~ command~ \token_to_str:N #1 \c_space_tl is~ not~
+    defined.
+  }
+  {
+    You've~ tried~ to~ renew~ the~ iupac~ command~ \token_to_str:N #1 ,~ but~
+    it~ doesn't~ exist.~ Use~ \token_to_str:N \NewChemIUPAC \c_space_tl
+    instead.
+  }
+
+\msg_new:nnnn { chemmacros } { let-iupac }
+  {
+    The~ iupac~ naming~ command~ \token_to_str:N #2 \c_space_tl is~ not~
+    defined.
+  }
+  {
+    You've~ tried~ to~ let~ the~ iupac~ command~ \token_to_str:N #1 ~ to~ the~
+    iupac~ command~ \token_to_str:N #2 ,~ but~ the~ latter~ doesn't~ exist.~
+    Use~ \token_to_str:N \NewChemIUPAC \c_space_tl instead~ or~declare~
+    \token_to_str:N #2 \c_space_tl first.
+  }
+
+\msg_new:nnnn { chemmacros } { ox }
+  { \token_to_str:N \ox \c_space_tl : ~ #1 ~ \msg_line_context: . }
+  { \token_to_str:N \ox \c_space_tl : ~ #1 ~ \msg_line_context: . }
+
+\msg_new:nnnn { chemmacros } { OX }
+  { \token_to_str:N \OX \c_space_tl : ~ #1 ~ \msg_line_context: . }
+  { \token_to_str:N \OX \c_space_tl : ~ #1 ~ \msg_line_context: . }
+
+\msg_new:nnnn { chemmacros } { redox }
+  { \token_to_str:N \redox \c_space_tl : ~ #1 ~ \msg_line_context: . }
+  { \token_to_str:N \redox \c_space_tl : ~ #1 ~ \msg_line_context: . }
+
+\msg_new:nnnn { chemmacros } { chemfig }
+  {
+    You~ need~ to~ load~ the~ `chemfig'~ package~ in~ order~ to~ make~
+    \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl work~
+    properly~ \msg_line_context: .
+  }
+  {
+    You~ need~ to~ load~ the~ `chemfig'~ package~ in~ order~ to~ make~
+    \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl work~
+    properly~ \msg_line_context: .
+  }
+
+\msg_new:nnnn { chemmacros } { new-state }
+  {
+    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
+    already~ exists.~ You~ need~ to~ use~ \token_to_str:N \RenewChemState
+    \c_space_tl to~ alter~ it~ \msg_line_context: .
+  }
+  {
+    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
+    already~ exists.~ You~ need~ to~ use~ \token_to_str:N \RenewChemState
+    \c_space_tl to~ alter~ it~ \msg_line_context: .
+  }
+
+\msg_new:nnnn { chemmacros } { renew-state }
+  {
+    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
+    isn't~ set~ up~ yet.~ You~ need~ to~ use~ \token_to_str:N
+    \NewChemState \c_space_tl to~ create~ it~ \msg_line_context: .
+  }
+  {
+    The~ state~ \exp_after:wN \token_to_str:N \cs:w #1 \cs_end: \c_space_tl
+    isn't~ set~ up~ yet.~ You~ need~ to~ use~ \token_to_str:N
+    \NewChemState \c_space_tl to~ create ~it~ \msg_line_context: .
+  }
+
+\msg_new:nnn { chemmacros } { state-syntax }
+  {
+    You're~ using~ a~ no~ longer~ recommended~ syntax~ to~ (re-)define~ a~
+    state~ variable~ \msg_line_context: .~ This~ syntax~ may~ deprecate~ and~
+    be~ removed~ in~ the~ future.
+  }
+
+% declare an option as deprecated:
+\cs_new_protected:Npn \chemmacros_option_deprecated:n #1
+  { \msg_warning:nnn { chemmacros } { option-deprecated } { #1 } }
+
+% define a deprecated command with hints to the corresponding new one:
+\cs_new_protected:Npn \chemmacros_define_deprecated:NN #1#2
+  {
+    \cs_set_protected:Npn #1
+      {
+        \msg_warning:nnxx { chemmacros } { command-deprecated }
+          { #1 } { #2 }
+        #2
+      }
+  }
+
+\NewDocumentCommand \DeclareChemDeprecated { mm }
+  { \chemmacros_define_deprecated:NN #1 #2 }
+
+% define a command as dropped!
+\cs_new_protected:Npn \chemmacros_define_dropped:N #1
+  {
+    \cs_set_protected:Npn #1
+      { \msg_error:nnn { chemmacros } { command-dropped } { #1 } }
+  }
+
+\NewDocumentCommand \DeclareChemDropped { m }
+  { \chemmacros_define_dropped:N #1 }
+
+% --------------------------------------------------------------------------
+% temporary variables
+\tl_new:N  \l__chemmacros_tmpa_tl
+\tl_new:N  \l__chemmacros_tmpb_tl
+\int_new:N \l__chemmacros_tmpa_int
+\box_new:N \l__chemmacros_tmpa_box
+
+% --------------------------------------------------------------------------
+% language settings:
+\bool_new:N      \l__chemmacros_language_auto_bool
+\bool_set_true:N \l__chemmacros_language_auto_bool
+% this token list will hold the chosen language for chemmacros; since the
+% language is either chosen automatically or by option it is only available at
+% begin document
+\tl_new:N        \l_chemmacros_language_tl
+\tl_set:Nn       \l_chemmacros_language_tl { english }
+\tl_new:N        \l__chemmacros_current_language_tl
+
+% translate the key #1
+\cs_new:Npn \chemmacros_translate:n #1
+  {
+    \bool_if:NTF \l__chemmacros_language_auto_bool
+      { \GetTranslation{#1} }
+      { \GetTranslationFor{\l_chemmacros_language_tl}{#1} }
+  }
+
+\AtBeginDocument{
+  \bool_if:NTF \l__chemmacros_language_auto_bool
+    {
+      \tl_set:Nx \l_chemmacros_language_tl
+        { \@trnslt@language{\@trnslt@current@language} }
+    }
+    {
+      \tl_set_eq:NN
+        \l_chemmacros_language_tl
+        \l__chemmacros_current_language_tl
+    }
+}
+
+% --------------------------------------------------------------------------
+% package options
+%   circled     => circle charges
+%   detect-bold => behaviour when font series bold
+%   EZ          => cool or chemmacros version of \E
+%   german      => change pKA => pKS etc
+%   iupac       => behaviour of nomenclature commands
+%   ngerman     => an alias :)
+%   ghsystem    => load ghsystem or don't
+%   method      => use `chemformula' or `mhchem'
+%   strict      => errors or warnings
+%   synchronize => let particles et.al. adapt chemformula's font selection
+%   ugreek      => behaviour of \chemDelta, \chemalpha, ...
+%   version=1   => compatibility for documents set with v1.*
+%   xspace      => add an \xspace after a whole bunch of macros
+
+% this boolean has to be public since the other packages of the bundle may
+% want to know its value
+
+\bool_new:N \l__chemmacros_detect_bold_bool
+\bool_set_true:N \l__chemmacros_detect_bold_bool
+
+\bool_new:N \l__chemmacros_option_greek_set_bool
+\bool_new:N \l__chemmacros_use_upgreek_bool
+\bool_new:N \l__chemmacros_use_textgreek_bool
+\bool_new:N \l__chemmacros_use_kpfonts_bool
+\bool_new:N \l__chemmacros_use_newtx_bool
+
+\cs_new:Npn \chemmacros_inner_font: {}
+
+\keys_define:nn { chemmacros / option }
+  {
+    compatibility      .code:n = ,
+    bpchem             .code:n = \chemmacros_option_deprecated:n { bpchem } ,
+    circletype         .choice: ,
+    circletype / math  .code:n  =
+      { \bool_set_false:N \l__chemmacros_circled_chem_bool } ,
+    circletype / chem  .code:n  =
+      { \bool_set_true:N \l__chemmacros_circled_chem_bool } ,
+    circletype         .default:n = chem ,
+    circled            .choice: ,
+    circled / none     .code:n =
+      {
+        \bool_set_false:N \l__chemmacros_circled_bool
+        \bool_set_false:N \l__chemmacros_circled_formal_bool
+      } ,
+    circled / formal   .code:n =
+      {
+        \bool_set_true:N \l__chemmacros_circled_bool
+        \bool_set_true:N \l__chemmacros_circled_formal_bool
+      } ,
+    circled / all      .code:n =
+      {
+        \bool_set_true:N \l__chemmacros_circled_bool
+        \bool_set_false:N \l__chemmacros_circled_formal_bool
+      } ,
+    circled            .default:n  = all ,
+    detect-bold        .code:n = \chemmacros_option_deprecated:n { detect-bold } ,
+    EZ                 .code:n = \chemmacros_option_deprecated:n { EZ } ,
+    german             .code:n     =
+      \tl_set:Nn \l__chemmacros_current_language_tl { german } ,
+    ngerman            .code:n     =
+      \tl_set:Nn \l__chemmacros_current_language_tl { ngerman } ,
+    ghsystem           .bool_set:N = \l__chemmacros_ghsystem_bool ,
+    ghsystem           .default:n  = true ,
+    iupac              .choice: ,
+    iupac / restricted .code:n     =
+      \bool_set_true:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
+    iupac / auto       .code:n     =
+      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_false:N \l__chemmacros_iupac_strict_bool ,
+    iupac / strict     .code:n     =
+      \bool_set_false:N \l__chemmacros_iupac_restricted_bool
+      \bool_set_true:N \l__chemmacros_iupac_strict_bool ,
+    language           .code:n     =
+      \tl_if_eq:nnTF { #1 } { auto }
+        { \bool_set_true:N \l__chemmacros_language_auto_bool }
+        {
+          \bool_set_false:N \l__chemmacros_language_auto_bool
+          \tl_set:Nn \l__chemmacros_current_language_tl { #1 }
+        } ,
+    method             .choice: ,
+    method / chemformula   .code:n     =
+      \chemmacros_option_deprecated:n { method } ,
+    method / mhchem    .code:n     =
+      \chemmacros_option_deprecated:n { method } ,
+    Nu                 .choice: ,
+    Nu / mathspec      .code:n     =
+     \bool_set_true:N \l__chemmacros_Nu_mathspec_bool ,
+    Nu / chemmacros    .code:n     =
+     \bool_set_false:N \l__chemmacros_Nu_mathspec_bool ,
+    strict             .code:n     =
+      \chemmacros_option_deprecated:n { strict } ,
+    synchronize        .choice: ,
+    synchronize / true .code:n     =
+      \cs_set_eq:NN \chemmacros_inner_font: \chemformula_font_inner: ,
+    synchronize / false .code:n = \cs_set:Nn \chemmacros_inner_font: {} ,
+    synchronize        .default:n  = true ,
+    greek              .choice: ,
+    greek / upgreek    .code:n     =
+      \chemgreek_activate_mapping:n { upgreek }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / textgreek   .code:n    =
+      \chemgreek_activate_mapping:n { textgreek }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / kpfonts    .code:n     =
+      \chemgreek_activate_mapping:n { kpfonts }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / newtx      .code:n     =
+      \chemgreek_activate_mapping:n { newtx }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / mathdesign .code:n     =
+      \chemgreek_activate_mapping:n { mathdesign }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / fourier    .code:n     =
+      \chemgreek_activate_mapping:n { fourier }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / textalpha  .code:n     =
+      \chemgreek_activate_mapping:n { textalpha }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / math       .code:n     =
+      \chemgreek_activate_mapping:n { default }
+      \bool_set_true:N \l__chemmacros_option_greek_set_bool ,
+    greek / auto       .code:n     =
+      \bool_set_false:N \l__chemmacros_option_greek_set_bool ,
+    greek              .default:n  = auto ,
+    upgreek            .code:n = \chemmacros_option_deprecated:n { upgreek } ,
+    version            .code:n = \chemmacros_option_deprecated:n { version } ,
+    cmversion          .code:n = \chemmacros_option_deprecated:n { cmversion } ,
+    cmversion          .choice: ,
+    xspace             .bool_set:N = \l__chemmacros_xspace_bool ,
+    xspace             .default:n  = true
+  }
+
+
+
+\ProcessKeysOptions { chemmacros / option }
+
+% --------------------------------------------------------------------------
+% set up a few things:
+% - is `ghsystem' requested?
+% - do we need `xspace'?
+% - what about the greek letters?
+
+\seq_new:N  \l__chemmacros_greek_packages_seq
+\prop_new:N \l__chemmacros_greek_mapping_prop
+
+\cs_new_protected:Npn \chemmacros_add_greek_package_mapping:nn #1#2
+  {
+    \seq_put_right:Nn \l__chemmacros_greek_packages_seq {#1}
+    \prop_put:Nnn \l__chemmacros_greek_mapping_prop {#1} {#2}
+  }
+
+\cs_generate_variant:Nn \chemgreek_activate_mapping:n { V }
+
+\cs_new_protected:Npn \__chemmacros_select_greek_mapping:n #1
+  {
+    \bool_if:NF \l__chemmacros_option_greek_set_bool
+      {
+        \@ifpackageloaded { #1 }
+          {
+            \prop_get:NnN
+              \l__chemmacros_greek_mapping_prop
+              { #1 }
+              \l__chemmacros_tmpa_tl
+            \chemgreek_activate_mapping:V \l__chemmacros_tmpa_tl
+            \bool_set_true:N \l__chemmacros_option_greek_set_bool
+            \seq_map_break:
+          }
+          { }
+      }
+  }
+
+\chemmacros_add_greek_package_mapping:nn {upgreek}    {upgreek}
+\chemmacros_add_greek_package_mapping:nn {textgreek}  {textgreek}
+\chemmacros_add_greek_package_mapping:nn {mathdesign} {mathdesign}
+\chemmacros_add_greek_package_mapping:nn {kpfonts}    {kpfonts}
+\chemmacros_add_greek_package_mapping:nn {newtxmath}  {newtx}
+\chemmacros_add_greek_package_mapping:nn {fourier}    {fourier}
+\chemmacros_add_greek_package_mapping:nn {textalpha}  {textalpha}
+
+\AtEndPreamble
+  {
+    \bool_if:NT \l__chemmacros_ghsystem_bool
+      { \RequirePackage { ghsystem } }
+    \bool_if:NT \l__chemmacros_xspace_bool
+      { \RequirePackage { xspace } }
+    \seq_map_function:NN
+      \l__chemmacros_greek_packages_seq
+      \__chemmacros_select_greek_mapping:n
+  }
+
+\cs_new_protected:Npn \chemmacros_xspace:
+  { \bool_if:NT \l__chemmacros_xspace_bool { \xspace } }
+
+% --------------------------------------------------------------------------
+% TikZ drawings - helper macros
+\cs_new_protected:Npn \chemmacros_tikz_picture:nn #1#2
+  { \tikzpicture[#1] #2 \endtikzpicture }
+\cs_generate_variant:Nn \chemmacros_tikz_picture:nn { fn,xn }
+
+\cs_new_protected:Npn \chemmacros_tikz_draw:n #1
+  { \draw[#1] }
+\cs_generate_variant:Nn \chemmacros_tikz_draw:n { f,x }
+
+\cs_new_protected:Npn \chemmacros_tikz_node:n #1
+  { \node[#1] }
+\cs_generate_variant:Nn \chemmacros_tikz_node:n { f,x }
+
+\cs_new_protected:Npn \chemmacros_tikz_shade:n #1
+  { \shade[#1] }
+\cs_generate_variant:Nn \chemmacros_tikz_shade:n { f,x }
+
+\cs_new_protected:Npn \chemmacros_tikz_shadedraw:n #1
+  { \shadedraw[#1] }
+\cs_generate_variant:Nn \chemmacros_tikz_shadedraw:n { f,x }
+
+\cs_new_protected:Npn \chemmacros_tikz_node_in_draw:n #1
+  { node[#1] }
+\cs_generate_variant:Nn \chemmacros_tikz_node_in_draw:n { f,x }
+
+% --------------------------------------------------------------------------
+% a few general functions:
+\cs_new_eq:NN \chemmacros_leave_vmode:   \chemformula_leave_vmode:
+\cs_new_eq:NN \chemmacros_ignore_spaces: \tex_ignorespaces:D
+\cs_new_eq:NN \chemmacros_nobreak:       \chemformula_nobreak:
+\cs_new_eq:NN \chemmacros_allow_break:   \chemformula_allow_break:
+\cs_new_eq:NN \chemmacros_skip_nobreak:N \chemformula_skip_nobreak:N
+\cs_new:Npn   \chemmacros_remove_backslash:N #1
+  { \exp_after:wN \use_none:n \token_to_str:N #1 }
+
+\prg_new_protected_conditional:Npnn \chemmacros_if_is_cs:n #1 { T,F,TF }
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl { \token_if_cs:NTF #1 { } { x } }
+    \tl_if_blank:VTF \l__chemmacros_tmpa_tl
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+% detection and handling of bold face:
+\prg_new_protected_conditional:Npnn \chemmacros_if_bold: { T,F,TF }
+  {
+    \seq_if_in:NVTF \l__chemmacros_if_bf_seq \f@series
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\seq_new:N  \l__chemmacros_if_bf_seq
+
+\seq_set_split:Nnn \l__chemmacros_if_bf_seq { , }
+  {
+    b , bc , bm , bx , bux ,
+    eb , ebc , ebx , mb ,
+    sb , sbc , sbx ,
+    ub , ubc , ubx
+  }
+
+\cs_new_protected:Npn \chemmacros_bm:n #1
+  {
+    \bool_if:NTF \l__chemmacros_detect_bold_bool
+      { \bm { #1 } }
+      { #1 }
+  }
+
+\cs_new_protected:Npn \chemmacros_bf:n #1
+  {
+    \bool_if:NTF \l__chemmacros_detect_bold_bool
+      { { \normalfont \bfseries #1 } }
+      { { \normalfont #1 } }
+  }
+
+\cs_new_protected:Npn \chemmacros_detect_bold:n #1
+  {
+    \chemmacros_if_bold:TF
+      {
+        \mode_if_math:TF
+          { \chemmacros_bm:n { #1 } }
+          { \chemmacros_bf:n { #1 } }
+      }
+      { #1 }
+  }
+
+% ---------------------------------------------------------------------------
+% transition state symbol
+\cs_new_protected:Npn \__chemmacros_transition_state:
+  {
+    \text
+      {
+        \skip_horizontal:n { .1ex }
+        \hbox_overlap_right:n
+          { \rule { .6ex } { 0pt } \rule { .05ex } { 1.3ex } }
+        \hbox_overlap_right:n { \rule [ .4ex ] { 1.3ex } { .05ex } }
+        \rule [ .85ex ] { 1.3ex } { .05ex }
+        \skip_horizontal:n { .1ex }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_transition_state:
+  {
+    \ensuremath
+      {
+        \mathchoice
+          { \displaystyle }
+          { \textstyle }
+          { \scriptstyle }
+          { \scriptscriptstyle }
+        \__chemmacros_transition_state:
+      }
+  }
+
+% \DeclareDocumentCommand?
+\cs_new_eq:NN \transitionstatesymbol \chemmacros_transition_state:
+
+% --------------------------------------------------------------------------
+% let's make use of `chemformula' inside some of `chemmacros' commands:
+\cs_new_protected:Nn \chemmacros_atom:n
+  {
+    \mode_if_math:TF
+      { \text { \chemmacros_inner_font: #1 } }
+      { \group_begin: \chemmacros_inner_font: #1 \group_end: }
+  }
+\cs_generate_variant:Nn \chemmacros_atom:n { V }
+
+\cs_new_protected:Npn \chemmacros_text:n #1
+  { \mode_if_math:TF { \text { #1 } } { #1 } }
+
+\tl_new:N \l__chemmacros_chemformula_tl
+
+\cs_new_protected:Npn \chemmacros_chemformula:n #1
+  {
+    \group_begin:
+      \cs_set_eq:NN \chemformula_font_inner: \chemmacros_inner_font:
+      \chemformula_chcpd:nn {} { #1 }
+    \group_end:
+  }
+\cs_generate_variant:Nn \chemmacros_chemformula:n { x,V }
+
+% --------------------------------------------------------------------------
+% particles, charges
+\NewDocumentCommand \NewChemParticle { mm }
+  {
+    \cs_if_free:NTF #1
+      { \chemmacros_define_particle:Nn #1 { #2 } }
+      { \msg_error:nnn { chemmacros } { new-particle } { #1 } }
+  }
+
+\NewDocumentCommand \RenewChemParticle { mm }
+  {
+    \cs_if_free:NTF #1
+      { \msg_error:nnn { chemmacros } { renew-particle } { #1 } }
+      { \chemmacros_define_particle:Nn #1 { #2 } }
+  }
+
+\NewDocumentCommand \DeclareChemParticle { mm }
+  { \chemmacros_define_particle:Nn #1 { #2 } }
+
+\cs_new_protected:Nn \chemmacros_define_particle:Nn
+  {
+    \cs_set_protected:Npn #1
+      {
+        \chemformula_chcpd:nn {} { #2 }
+        \chemmacros_xspace:
+      }
+  }
+
+\NewChemParticle \el  { e- }
+\NewChemParticle \prt { p+ }
+\NewChemParticle \ntr { n^0 }
+
+% --------------------------------------------------------------------------
+% charges
+% circled charge signs: they are defined in the `chemformula' module:
+% use directly:
+
+\cs_new_protected:Npn \fplus  { { \chemformula_fplus:  } }
+\cs_new_protected:Npn \fminus { { \chemformula_fminus: } }
+
+% change output depending on circled-option
+\cs_new_eq:NN \chemmacros_plus: \chemformula_plus:
+\cs_new_eq:NN \chemmacros_minus: \chemformula_minus:
+
+\cs_new_protected:Npn \chemmacros_formal_plus:
+  {
+    \group_begin:
+      \bool_set_true:N \l_chemformula_formal_charges_bool
+      \chemformula_plus:
+    \group_end:
+  }
+
+\cs_new_protected:Npn \chemmacros_formal_minus:
+  {
+    \group_begin:
+      \bool_set_true:N \l_chemformula_formal_charges_bool
+      \chemformula_minus:
+    \group_end:
+  }
+
+\cs_new_protected:Npn \chemmacros_charge:n #1
+  {
+    \chemformula_superscript:n
+      { \chemmacros_detect_bold:n { #1 } }
+  }
+
+\keys_define:nn { chemmacros / charges }
+  { append .code:n = \chemmacros_option_deprecated:n { append } }
+
+\NewDocumentCommand \mch { o }
+  {
+    \IfNoValueTF { #1 }
+      { \chemmacros_charge:n { \chemmacros_minus: } }
+      { \chemmacros_charge:n { #1 \chemmacros_minus: } }
+  }
+
+\NewDocumentCommand \pch { o }
+  {
+    \IfNoValueTF { #1 }
+      { \chemmacros_charge:n { \chemmacros_plus: } }
+      { \chemmacros_charge:n { #1 \chemmacros_plus: } }
+  }
+
+\NewDocumentCommand \fmch { o }
+  {
+    \IfNoValueTF { #1 }
+      { \chemmacros_charge:n { \chemmacros_formal_minus: } }
+      { \chemmacros_charge:n { #1 \chemmacros_formal_minus: } }
+  }
+
+\NewDocumentCommand \fpch { o }
+  {
+    \IfNoValueTF { #1 }
+      { \chemmacros_charge:n { \chemmacros_formal_plus: } }
+      { \chemmacros_charge:n { #1 \chemmacros_formal_plus: } }
+  }
+
+\tl_new:N  \l__chemmacros_partial_charge_format_tl
+\tl_set:Nn \l__chemmacros_partial_charge_format_tl { \tiny }
+
+\cs_new_protected:Npn \delm
+  {
+    \mbox {
+      \l__chemmacros_partial_charge_format_tl
+      \c_math_toggle_token \delta \chemmacros_minus: \c_math_toggle_token
+    }
+    \chemmacros_xspace:
+  }
+\cs_new_protected:Npn \delp
+  {
+    \mbox {
+      \l__chemmacros_partial_charge_format_tl
+      \c_math_toggle_token \delta \chemmacros_plus: \c_math_toggle_token
+    }
+    \chemmacros_xspace:
+  }
+\cs_new_protected:Npn \fdelm
+  {
+    \mbox {
+      \l__chemmacros_partial_charge_format_tl
+      \c_math_toggle_token \delta \chemmacros_formal_minus: \c_math_toggle_token
+    }
+    \chemmacros_xspace:
+  }
+\cs_new_protected:Npn \fdelp
+  {
+    \mbox {
+      \l__chemmacros_partial_charge_format_tl
+      \c_math_toggle_token \delta \chemmacros_formal_plus: \c_math_toggle_token
+    }
+    \chemmacros_xspace:
+  }
+
+\cs_new_protected:Npn \scrm
+  { \ensuremath { \scriptstyle \chemmacros_minus: } }
+\cs_new_protected:Npn \scrp
+  { \ensuremath { \scriptstyle \chemmacros_plus: } }
+\cs_new_protected:Npn \fscrm
+  { \ensuremath { \scriptstyle \chemmacros_formal_minus: } }
+\cs_new_protected:Npn \fscrp
+  { \ensuremath { \scriptstyle \chemmacros_formal_plus: } }
+\cs_new_protected:Npn \fsscrm
+  { \ensuremath { \scriptscriptstyle \chemmacros_formal_minus: } }
+\cs_new_protected:Npn \fsscrp
+  { \ensuremath { \scriptscriptstyle \chemmacros_formal_plus: } }
+
+\keys_define:nn { chemmacros / charges }
+  {
+    partial-format .tl_set:N = \l__chemmacros_partial_charge_format_tl
+  }
+
+% --------------------------------------------------------------------------
+% ions, molecules
+% proton, hydroxide, hydronium/oxonium, water, nucleophile, electrophile
+\NewChemParticle \Hpl { H+ }
+\NewChemParticle \Hyd { OH- }
+\NewChemParticle \HtO { H3O+ }
+\NewChemParticle \El  { E+ }
+\NewChemParticle \water { H2O }
+
+\NewDocumentCommand \chemmacros_Nu:w { o }
+  {
+    \IfNoValueF { #1 } { \keys_set:nn { chemmacros / particle } { #1 } }
+    \bool_if:NTF \l__chemmacros_particle_elpair_bool
+      { \chemmacros_elpair:n { Nu } \mch }
+      { \chemmacros_chemformula:n { Nu- } }
+    \chemmacros_xspace:
+  }
+
+\AtBeginDocument
+  {
+    \bool_if:NTF \l__chemmacros_Nu_mathspec_bool
+      { \cs_set_eq:NN \Nuc \chemmacros_Nu:w }
+      { \cs_set_eq:NN \Nu \chemmacros_Nu:w }
+  }
+
+\cs_new_protected:Npn \chemmacros_ba:
+  {
+    \bool_if:NTF \l__chemmacros_particle_elpair_bool
+      { \chemmacros_elpair:n { ba } \mch }
+      { \chemmacros_chemformula:n { ba- } }
+    \chemmacros_xspace:
+  }
+
+\NewDocumentCommand \ba { o }
+  {
+    \group_begin:
+      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / particle } { #1 } }
+      \chemmacros_ba:
+    \group_end:
+  }
+
+\cs_new_protected:Npn \chemmacros_elpair:n #1
+  {
+    \bool_if:NTF \l__chemmacros_chemfig_bool
+      {
+        \bool_if:NTF \l__chemmacros_elpair_dots_bool
+          { \chlewis { 0: } { #1 } }
+          { \chlewis { 0| } { #1 } }
+%          { { \chemmacros_inner_font: #1 \chlewis { 0=| } { \vphantom { #1 } } } }
+      }
+      {
+        \msg_error:nnn { chemmacros } { chemfig } { #1 }
+        \chemmacros_atom:n { #1 }
+      }
+  }
+
+\bool_new:N \l__chemmacros_particle_elpair_bool
+\bool_new:N \l__chemmacros_elpair_dots_bool
+
+\keys_define:nn { chemmacros / particle }
+  {
+    elpair         .choice: ,
+    elpair / false .code:n    =
+      { \bool_set_false:N \l__chemmacros_particle_elpair_bool } ,
+    elpair / dots  .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_particle_elpair_bool
+        \bool_set_true:N \l__chemmacros_elpair_dots_bool
+      } ,
+    elpair / dash  .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_particle_elpair_bool
+        \bool_set_false:N \l__chemmacros_elpair_dots_bool
+      } ,
+    elpair         .default:n = dots
+  }
+
+% --------------------------------------------------------------------------
+% IUPAC
+\prop_new:N \l__chemmacros_iupac_prop
+
+\cs_new_protected:Npn \chemmacros_new_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
+      { \msg_error:nnn { chemmacros } { new-iupac } { #1 } }
+      {
+        \prop_put:NVn \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          { #2 }
+      }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_define_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_put:NVn \l__chemmacros_iupac_prop
+      \l__chemmacros_tmpa_tl
+      { #2 }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_iupac:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \prop_if_in:NVTF \l__chemmacros_iupac_prop \l__chemmacros_tmpa_tl
+      {
+        \prop_put:NVn \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          { #2 }
+      }
+      { \msg_error:nnn { chemmacros } { renew-iupac } { #1 } }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_let_iupac:NN #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \tl_set:Nx \l__chemmacros_tmpb_tl
+      { \chemmacros_remove_backslash:N #2 }
+    \prop_get:NVNTF \l__chemmacros_iupac_prop
+      \l__chemmacros_tmpb_tl
+      \l__chemmacros_tmpc_tl
+      {
+        \prop_put:NVV \l__chemmacros_iupac_prop
+          \l__chemmacros_tmpa_tl
+          \l__chemmacros_tmpc_tl
+      }
+      { \msg_error:nnnn { chemmacros } { let-iupac } { #1 } { #2 } }
+    \chemmacros_make_iupac:
+  }
+
+\cs_new_protected:Npn \chemmacros_define_deprecated_iupac:NN #1#2
+  {
+    \chemmacros_define_iupac:Nn #1
+      {
+        \msg_warning:nnnn { chemmacros } { command-deprecated }
+          { #1 } { #2 }
+        #2
+      }
+  }
+
+
+\cs_new_protected:Npn \chemmacros_make_iupac:
+  {
+    \bool_if:NT \l__chemmacros_in_document_bool
+      {
+        \bool_if:NTF \l__chemmacros_inside_iupac_bool
+          {
+            \prop_map_inline:Nn \l__chemmacros_iupac_prop
+              { \cs_set_protected:cpn { ##1 } { ##2 } }
+          }
+          {
+            \bool_if:NF \l__chemmacros_iupac_restricted_bool
+              {
+                \bool_if:NTF \l__chemmacros_iupac_strict_bool
+                  {
+                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
+                      { \cs_set_protected:cpn { ##1 } { ##2 } }
+                  }
+                  {
+                    \prop_map_inline:Nn \l__chemmacros_iupac_prop
+                      {
+                        \cs_if_exist:cF { ##1 }
+                          { \cs_set_protected:cpn { ##1 } { ##2 } }
+                      }
+                  }
+              }
+          }
+      }    
+  }
+
+\AtBeginDocument { \chemmacros_make_iupac: }
+
+\NewDocumentCommand \DeclareChemIUPAC { mm }
+  { \chemmacros_define_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \NewChemIUPAC { mm }
+  { \chemmacros_new_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \RenewChemIUPAC { mm }
+  { \chemmacros_renew_iupac:Nn #1 { #2 } }
+
+\NewDocumentCommand \LetChemIUPAC { mm }
+  { \chemmacros_let_iupac:NN #1 #2 }
+
+\NewDocumentCommand \DeprecateChemIUPAC { mm }
+  { \chemmacros_define_deprecated_iupac:NN #1 #2 }
+
+% stereo descriptors and other nomenclature commands
+% Cahn-Ingold-Prelog
+\dim_new:N  \l__chemmacros_cip_kern_dim
+\dim_set:Nn \l__chemmacros_cip_kern_dim { .075em }
+
+\keys_define:nn { chemmacros / iupac }
+  { cip-kern .dim_set:N = \l__chemmacros_cip_kern_dim }
+
+\NewDocumentCommand \cip { m }
+  { \chemmacros_cip:n { #1 } }
+
+\cs_new_protected:Npn \chemmacros_cip:n #1
+  { ( \textit{#1} \tex_kern:D \l__chemmacros_cip_kern_dim ) }
+
+\DeprecateChemIUPAC \Rcip \rectus
+\DeprecateChemIUPAC \Scip \sinister
+
+\NewChemIUPAC \rectus   { \cip { R } }
+\NewChemIUPAC \sinister { \cip { S } }
+
+\LetChemIUPAC \R \rectus
+\LetChemIUPAC \S \sinister
+
+% TikZ needs : to be other
+\ExplSyntaxOff
+\protected\def\chemmacros@sconf#1%
+  {%
+    \begingroup
+    \tikz[baseline,text height=1.5ex,text depth=.25ex]
+      {
+        \node[anchor=base] (chemmacros@@Sconf) {#1} ;
+        \draw[->,thick,rotate=90]
+          ($(chemmacros@@Sconf.center)+(20:.8em)$) arc (20:340:.8em);
+      }%
+    \endgroup
+  }
+
+\protected\def\chemmacros@rconf#1%
+  {%
+    \begingroup
+    \tikz[baseline,text height=1.5ex,text depth=.25ex]
+      {
+        \node[anchor=base] (chemmacros@@Rconf) {#1} ;
+        \draw[<-,thick,rotate=90]
+          ($(chemmacros@@Rconf.center)+(20:.8em)$) arc (20:340:.8em) ;
+      }%
+    \endgroup
+  }
+\ExplSyntaxOn
+
+\NewDocumentCommand \Sconf { O{S} } { \chemmacros@sconf { #1 } }
+\NewDocumentCommand \Rconf { O{R} } { \chemmacros@rconf { #1 } }
+
+% E(ntgegen)/Z(usammen)
+\NewChemIUPAC \entgegen { \cip { E } }
+\NewChemIUPAC \zusammen { \cip { Z } }
+
+\LetChemIUPAC \E \entgegen
+\LetChemIUPAC \Z \zusammen
+
+% cis/trans
+\NewChemIUPAC \cis   { \textit { cis } }
+\NewChemIUPAC \trans { \textit { trans } }
+
+% fac/mer
+\NewChemIUPAC \fac { \textit { fac } }
+\NewChemIUPAC \mer { \textit { mer } }
+
+% tert
+\NewChemIUPAC \tert  { \textit { tert } }
+
+% Fischer
+\NewChemIUPAC \dexter { \textsc { d } }
+\NewChemIUPAC \laevus { \textsc { l } }
+
+\LetChemIUPAC \D \dexter
+\LetChemIUPAC \L \laevus
+
+% ortho/meta/para
+\NewChemIUPAC \ortho { \textit { o } }
+\NewChemIUPAC \meta  { \textit { m } }
+\NewChemIUPAC \para  { \textit { p } }
+
+% syn/anti
+\NewChemIUPAC \syn  { \textit { syn } }
+\NewChemIUPAC \anti { \textit { anti } }
+
+% coordination chemistry
+\bool_new:N \l__chemmacros_bridge_super_bool
+
+\keys_define:nn { chemmacros / iupac }
+  {
+    bridge-number         .choice: ,
+    bridge-number / sub   .code:n     =
+      \bool_set_false:N \l__chemmacros_bridge_super_bool ,
+    bridge-number / super .code:n     =
+      \bool_set_true:N \l__chemmacros_bridge_super_bool ,
+    coord-use-hyphen      .bool_set:N = \l__chemmacros_coord_use_hyphen_bool ,
+    coord-use-hyphen      .default:n  = true
+  }
+
+\cs_new_protected:Npn \chemformula_hapto:n #1
+  {
+    \chemeta \chemformula_superscript:n { #1 }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+\cs_new_protected:Npn \chemformula_dento:n #1
+  {
+    \chemkappa \chemformula_superscript:n { #1 }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+\cs_new_protected:Npn \chemformula_bridge:n #1
+  {
+    \chemmu
+    \tl_if_blank:nF { #1 }
+      {
+        \bool_if:NTF \l__chemmacros_bridge_super_bool
+          { \chemformula_superscript:n { #1 } }
+          { \chemformula_subscript:n { #1 } }
+      }
+    \bool_if:NT \l__chemmacros_coord_use_hyphen_bool
+      { \chemmacros_break_point_hyphen: }
+  }
+
+\NewChemIUPAC \hapto  { \chemformula_hapto:n }
+\NewChemIUPAC \dento  { \chemformula_dento:n }
+\NewChemIUPAC \bridge { \chemformula_bridge:n }
+
+% attachments to heteroatoms / added hydrogen
+\NewChemIUPAC \hydrogen   { \textit { H } }
+\NewChemIUPAC \oxygen     { \textit { O } }
+\NewChemIUPAC \nitrogen   { \textit { N } }
+\NewChemIUPAC \sulfur     { \textit { S } }
+\NewChemIUPAC \phosphorus { \textit { P } }
+
+\LetChemIUPAC \H  \hydrogen
+\LetChemIUPAC \O  \oxygen
+\LetChemIUPAC \N  \nitrogen
+\LetChemIUPAC \Sf \sulfur
+\LetChemIUPAC \P  \phosphorus
+
+% language specific settings
+\AtBeginDocument
+  {
+    \bool_if:NT \l__chemmacros_italian_bool
+      {
+        \NewChemIUPAC \sin  { \textit { sin } }
+        \NewChemIUPAC \ter  { \textit { ter } }
+      }
+  }
+
+% greek letters
+\NewChemIUPAC \a { \chemalpha }
+\NewChemIUPAC \b { \chembeta }
+\NewChemIUPAC \g { \chemgamma }
+\NewChemIUPAC \d { \chemdelta }
+\NewChemIUPAC \k { \chemkappa }
+\NewChemIUPAC \m { \chemmu }
+\NewChemIUPAC \n { \chemeta }
+\NewChemIUPAC \w { \chemomega }
+
+% \iupac (basically the same as bpchem's \IUPAC)
+% - allows multiple breaking points as compound names can get really long and
+%   especially in multicolumn documents can span more than two lines
+% - add a (very) little space before the hyphen and a little negative space
+%   after it
+% - add a little space at breaking points if not broken
+% - enables all naming commands regardless if they're definied otherwise or not
+\cs_new_protected:Nn \chemmacros_allow_hyphens:
+  {
+    \chemmacros_nobreak:
+    \skip_horizontal:N \c_zero_dim
+  }
+
+\dim_new:N  \l__chemmacros_iupac_hyphen_pre_dim
+\dim_set:Nn \l__chemmacros_iupac_hyphen_pre_dim { .01em }
+\dim_new:N  \l__chemmacros_iupac_hyphen_post_dim
+\dim_set:Nn \l__chemmacros_iupac_hyphen_post_dim { -.03em }
+\dim_new:N  \l__chemmacros_iupac_break_dim
+\dim_set:Nn \l__chemmacros_iupac_break_dim { .03em }
+
+\keys_define:nn { chemmacros / iupac }
+  {
+    hyphen-pre-space  .dim_set:N = \l__chemmacros_iupac_hyphen_pre_dim ,
+    hyphen-post-space .dim_set:N = \l__chemmacros_iupac_hyphen_post_dim ,
+    break-space       .dim_set:N = \l__chemmacros_iupac_break_dim
+  }
+
+\cs_new_protected:Nn \chemmacros_break_point_hyphen:
+  {
+    \chemmacros_nobreak:
+    \tex_discretionary:D { - } { }
+      {
+        \tex_kern:D \l__chemmacros_iupac_hyphen_pre_dim
+        -
+        \tex_kern:D \l__chemmacros_iupac_hyphen_post_dim
+      }
+    \chemmacros_allow_hyphens:
+  }
+
+\cs_new_protected:Npn \chemmacros_break_point:
+  {
+    \chemmacros_nobreak:
+    \tex_discretionary:D { - } { }
+      { \tex_kern:D \l__chemmacros_iupac_break_dim }
+    \chemmacros_allow_hyphens:
+  }
+
+\cs_new_protected:Npn \chemmacros_superscript:n #1
+  { \mode_if_math:TF { \sb {#1} } { \textsuperscript {#1} } }
+  
+\bool_new:N \l__chemmacros_inside_iupac_bool
+
+\char_set_active_eq:NN | \chemmacros_break_point:
+\char_set_active_eq:NN ^ \chemmacros_superscript:n
+
+\group_begin:
+\char_set_catcode_active:N \|
+\char_set_catcode_active:N \^
+
+\cs_new_protected:Npn \chemmacros_iupac:n #1
+  {
+    \group_begin:
+      \bool_set_true:N \l__chemmacros_inside_iupac_bool
+      \chemmacros_make_iupac:
+      \chemmacros_ignore_spaces:
+      \cs_set_eq:NN \- \chemmacros_break_point_hyphen:
+      \chemmacros_define_deprecated:NN \| |
+      \chemmacros_define_deprecated:NN \^ ^
+      \tl_set_rescan:Nnn \l__chemmacros_tmpa_tl
+        {
+          \char_set_catcode_active:N \|
+          \char_set_catcode_active:N \^
+        }
+        {#1}
+      \l__chemmacros_tmpa_tl
+    \group_end:
+  }
+
+\group_end:
+
+% Thanks to Joseph Wright and Enrico Gregorio for the help on the curious
+% redefinition of \- and the end of the compilation
+% see http://tex.stackexchange.com/q/42405/5049 for reference
+\cs_set_protected:Npx \| { \exp_not:o { \| } }
+\cs_set_protected:Npx \- { \exp_not:o { \- } }
+\cs_set_eq:NN \@dischyph \-
+
+\NewDocumentCommand \iupac { }
+  { \chemmacros_iupac:n }
+
+% --------------------------------------------------------------------------
+% latin phrases
+\tl_new:N  \l__chemmacros_latin_format_tl
+\tl_set:Nn \l__chemmacros_latin_format_tl { \itshape }
+
+\keys_define:nn { chemmacros / latin }
+  { format . tl_set:N = \l__chemmacros_latin_format_tl }
+
+\cs_new_protected:Npn \chemmacros_latin:n #1
+  { { \l__chemmacros_latin_format_tl #1 } }
+
+\prop_new:N \l__chemmacros_latin_prop
+
+\cs_new_protected:Npn \chemmacros_new_latin:Nn #1#2
+  {
+    \cs_if_free:NTF #1
+      {
+        \cs_new_protected:Npn #1
+          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
+        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
+      }
+      { \msg_error:nnn { chemmacros } { new-latin } { #1 } }
+  }
+
+\cs_new_protected:Npn \chemmacros_define_latin:Nn #1#2
+  {
+    \cs_if_free:NTF #1
+      {
+        \cs_new_protected:Npn #1
+          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
+        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
+      }
+      {
+        \cs_set_protected:Npn #1
+          { \chemmacros_latin:n { #2 } \chemmacros_xspace: }
+        \prop_put:Nnn \l__chemmacros_latin_prop { #1 } { #2 }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_latin:Nn #1#2
+  {
+    \prop_if_in:NnTF \l__chemmacros_latin_prop { #1 }
+      { \cs_set:Npn #1 { \chemmacros_latin:n { #2 } \chemmacros_xspace: } }
+      { \msg_error:nnn { chemmacros } { renew-latin } { #1 } }
+  }
+
+\NewDocumentCommand \NewChemLatin { mm }
+  { \chemmacros_new_latin:Nn #1 { #2 } }
+
+\NewDocumentCommand \RenewChemLatin { mm }
+  { \chemmacros_renew_latin:Nn #1 { #2 } }
+
+\NewDocumentCommand \DeclareChemLatin { mm }
+  { \chemmacros_define_latin:Nn #1 { #2 } }
+
+\AtBeginDocument
+  {
+    \bool_if:NTF \l__chemmacros_chemstyle_bool
+      {
+        \AfterPackage* { chemstyle }
+          {
+            \cs_undefine:N \invacuo
+            \cs_set_eq:NN \chemmacros_latin:n \cst@latin
+          }
+      }
+      {
+        \cs_new_eq:NN  \latin \chemmacros_latin:n
+      }
+    \NewChemLatin \insitu   { in~situ }
+    \NewChemLatin \abinitio { ab~initio }
+    \NewChemLatin \invacuo  { in~vacuo }
+  }
+
+% --------------------------------------------------------------------------- %
+% acid / base
+\tl_new:N  \l__chemmacros_k_acid_tl
+\tl_new:N  \l__chemmacros_k_base_tl
+\tl_new:N  \l__chemmacros_k_water_tl
+
+% \bool_new:N \l__chemmacros_subscript_lowercase_bool
+
+\tl_set:Nn \l__chemmacros_k_acid_tl
+  { \chemmacros_translate:n {K-acid} }
+
+\tl_set:Nn \l__chemmacros_k_base_tl
+  { \chemmacros_translate:n {K-base} }
+
+\tl_set:Nn \l__chemmacros_k_water_tl
+  { \chemmacros_translate:n {K-water} }
+
+\keys_define:nn { chemmacros / acid-base }
+  {
+    p-style             .choice: ,
+    p-style / slanted   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textsl ,
+    p-style / italics   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textit ,
+    p-style / upright   .code:n   = \cs_set_eq:NN \chemmacros_p_style:n \textup ,
+    K-acid              .tl_set:N = \l__chemmacros_k_acid_tl ,
+    K-base              .tl_set:N = \l__chemmacros_k_base_tl ,
+    K-water             .tl_set:N = \l__chemmacros_k_water_tl ,
+    subscript           .code:n   = \chemmacros_option_deprecated:n {#1}
+    % subscript / lowercase .code:n =
+    %   \bool_set_true:N \l__chemmacros_subscript_lowercase_bool ,
+    % subscript / uppercase .code:n =
+    %   \bool_set_false:N \l__chemmacros_subscript_lowercase_bool
+  }
+
+\cs_new_eq:NN \chemmacros_p_style:n \textup
+
+\cs_new_protected:Npn \Ka
+  {
+    \ensuremath
+      {
+        \chemmacros_detect_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_acid_tl }
+          }
+      }
+    \chemmacros_xspace:
+  }
+
+\cs_new_protected:Npn \Kb
+  {
+    \ensuremath
+      {
+        \chemmacros_detect_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_base_tl }
+          }
+      }
+    \chemmacros_xspace:
+  }
+
+\cs_new_protected:Npn \Kw
+  {
+    \ensuremath
+      {
+        \chemmacros_detect_bold:n
+          {
+            K
+            \c_math_subscript_token
+              { \l__chemmacros_k_water_tl }
+          }
+      }
+    \chemmacros_xspace:
+  }
+
+\cs_new_protected:Npn \chemmacros_p:n #1
+  {
+    \group_begin:
+      \mbox
+        {
+          \chemmacros_p_style:n { p }
+          \ensuremath { #1 }
+        }
+    \group_end:
+  }
+
+\NewDocumentCommand \p { m }
+  { \chemmacros_p:n { #1 } }
+
+\cs_new_protected:Npn \pH
+  {
+    \chemmacros_p:n { \chemmacros_chemformula:n { H } }
+    \chemmacros_xspace:
+  }
+
+\cs_new_protected:Npn \pOH
+  {
+    \chemmacros_p:n { \chemmacros_chemformula:n { OH } }
+    \chemmacros_xspace:
+  }
+
+\NewDocumentCommand \pKa { o }
+  {
+    \chemmacros_p:n
+      {
+        \Ka \IfNoValueF { #1 }
+          { {} \c_math_subscript_token { \chemmacros_detect_bold:n { #1 } } }
+      }
+    \chemmacros_xspace:
+  }
+
+\NewDocumentCommand \pKb { o }
+  {
+    \chemmacros_p:n
+      {
+        \Kb \IfNoValueF { #1 }
+          { {} \c_math_subscript_token { \chemmacros_detect_bold:n { #1 } } }
+      }
+    \chemmacros_xspace:
+  }
+
+% --------------------------------------------------------------------------
+% units
+\DeclareSIUnit { \atm        } { atm }
+\DeclareSIUnit { \atmosphere } { atm }
+\DeclareSIUnit { \calory     } { cal }
+\DeclareSIUnit { \cal        } { cal }
+
+\AtBeginDocument
+  {
+    \bool_if:NF \l__chemmacros_chemstyle_bool
+      {
+        \DeclareSIUnit { \cmc   } { \cubic\centi\metre }
+        \DeclareSIUnit { \molar } { \mole\per\cubic\deci\metre }
+        \DeclareSIUnit { \Molar } { \textsc{m} }
+      }
+  }
+
+\DeclareSIUnit { \moLar   } { \mole\per\liter }
+\DeclareSIUnit { \MolMass } { \gram\per\mole }
+\DeclareSIUnit { \normal  } { \textsc{n} }
+\DeclareSIUnit { \torr    } { torr }
+
+% --------------------------------------------------------------------------
+% reaction mechanisms
+% \mech[<type>]
+% <type> - substitutions: {}, 1, 2, se, 1e, 2e, ar
+%        - eliminations:  e, e1, e2, cb
+\tl_new:N \l__chemmacros_mech_type_tl
+\tl_new:N \l__chemmacros_mech_mol_tl
+\tl_new:N \l__chemmacros_mech_ar_tl
+
+\cs_new_protected:Npn \__chemmacros_set_mech:nnn #1#2#3
+  {
+    \tl_set:Nn \l__chemmacros_mech_type_tl { #1 }
+    \tl_set:Nn \l__chemmacros_mech_mol_tl  { #2 }
+    \tl_set:Nn \l__chemmacros_mech_ar_tl   { #3 }
+  }
+
+\keys_define:nn { chemmacros / mech }
+  {
+    type      .choice: ,
+    type /    .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type / 1  .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+            1
+          }
+          { }
+      } ,
+    type / 2  .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {N} }
+            \c_math_toggle_token
+            2
+          }
+          { }
+      } ,
+    type / se .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type / 1e .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+            1
+          }
+          { }
+      } ,
+    type / 2e .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+            2
+          }
+          { }
+      } ,
+    type / ar .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { S }
+          {
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {E} }
+            \c_math_toggle_token
+          }
+          { Ar - }
+      } ,
+    type / e  .code:n    =
+      { \__chemmacros_set_mech:nnn { E } { } { } } ,
+    type / e1 .code:n    =
+      { \__chemmacros_set_mech:nnn { E } { 1 } { } } ,
+    type / e2 .code:n    =
+      { \__chemmacros_set_mech:nnn { E } { 2 } { } } ,
+    type / cb .code:n    =
+      {
+        \__chemmacros_set_mech:nnn { E }
+          {
+            1
+            \c_math_toggle_token
+              \c_math_subscript_token { \text {cb} }
+            \c_math_toggle_token
+          }
+          { }
+      } ,
+    type      .default:n = 
+  }
+
+\cs_new_protected:Npn \chemmacros_mech:n #1
+  {
+    \tl_if_blank:nTF { #1 }
+      { \keys_set:nn { chemmacros / mech } { type } }
+      { \keys_set:nn { chemmacros / mech } { type = #1 } }
+    \mbox
+      {
+        \tl_use:N \l__chemmacros_mech_ar_tl
+        \tl_use:N \l__chemmacros_mech_type_tl
+        \tl_use:N \l__chemmacros_mech_mol_tl
+      }
+    \chemmacros_xspace:
+  }
+
+\NewDocumentCommand \mech { o }
+  {
+    \IfNoValueTF { #1 }
+      { \chemmacros_mech:n { } }
+      { \chemmacros_mech:n { #1 } }
+  }
+
+% --------------------------------------------------------------------------
+% oxidation numbers
+% \ox{<number>,<atom>}
+\bool_new:N       \l__chemmacros_ox_sign_bool
+\bool_new:N       \l__chemmacros_ox_integer_bool
+\bool_new:N       \l__chemmacros_ox_explicit_sign_bool
+\bool_set_false:N \l__chemmacros_ox_explicit_sign_bool
+\bool_new:N       \l__chemmacros_ox_format_roman_bool
+\bool_set_true:N  \l__chemmacros_ox_format_roman_bool
+\bool_new:N       \l__chemmacros_ox_decimal_marker_comma_bool
+\bool_set_false:N \l__chemmacros_ox_decimal_marker_comma_bool
+\bool_new:N       \l__chemmacros_ox_parse_bool
+\bool_set_true:N  \l__chemmacros_ox_parse_bool
+\bool_new:N       \l__chemmacros_ox_side_bool
+\bool_new:N       \l__chemmacros_ox_super_bool
+\bool_new:N       \l__chemmacros_ox_top_bool
+\bool_set_true:N  \l__chemmacros_ox_top_bool
+\bool_new:N       \l__chemmacros_ox_align_center_bool
+
+\int_new:N \l__chemmacros_ox_number_int
+\fp_new:N  \l__chemmacros_ox_number_fp
+
+\cs_new_protected:Npn \__chemmacros_ox_process_number:n #1
+  {
+    \bool_if:NTF \l__chemmacros_ox_parse_bool
+      {
+        \tl_if_in:nnTF { #1 } { / }
+          { \__chemmacros_ox_fraction:w #1 \q_stop }
+          {
+            \__chemmacros_ox_sign:n { #1 }
+            \__chemmacros_ox_value:n { #1 }
+          }
+      }
+      { #1 }
+  }
+
+\DeclareInstance { xfrac } { chemmacros-ox-frac } { text }
+  {
+    scale-factor        = 1.2 ,
+    denominator-bot-sep = -.5ex ,
+    numerator-top-sep   = -.3ex ,
+    slash-left-kern     = -.2em ,
+    slash-right-kern    = -.2em ,
+    slash-symbol-font   = lmr
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_fraction:w #1/#2 \q_stop
+  {
+    \bool_set_false:N \l__chemmacros_ox_format_roman_bool
+    \__chemmacros_ox_sign:n { #1 }
+    \bool_if:NTF \l__chemmacros_ox_side_bool
+      { \sfrac { \__chemmacros_ox_value:n { #1 } } { #2 } }
+      {
+        \sfrac [ chemmacros-ox-frac ]
+          { \__chemmacros_ox_value:n { #1 } }
+          { #2 }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_sign:n #1
+  {
+    \fp_compare:nNnT { #1 } > { 0 }
+      {
+        \bool_if:NT \l__chemmacros_ox_explicit_sign_bool
+          { \c_math_toggle_token + \c_math_toggle_token }
+      }
+    \fp_compare:nNnT { #1 } = { 0 }
+      {
+        \bool_if:NT \l__chemmacros_ox_explicit_sign_bool
+          { \c_math_toggle_token \pm \c_math_toggle_token }
+      }
+    \fp_compare:nNnT { #1 } < { 0 }
+      { \c_math_toggle_token - \c_math_toggle_token }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_value:n #1
+  {
+    \fp_set:Nn \l__chemmacros_ox_number_fp { abs(#1) }
+    \__chemmacros_ox_is_integer:V \l__chemmacros_ox_number_fp
+    \bool_if:NTF \l__chemmacros_ox_format_roman_bool
+      { \__chemmacros_fp_to_Roman:V \l__chemmacros_ox_number_fp }
+      {
+        \bool_if:NTF \l__chemmacros_ox_integer_bool
+          {
+            \c_math_toggle_token
+              \__chemmacros_fp_to_arabic:V \l__chemmacros_ox_number_fp
+            \c_math_toggle_token
+          }
+          {
+            \c_math_toggle_token
+              \__chemmacros_fp_show:V \l__chemmacros_ox_number_fp
+            \c_math_toggle_token
+          }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_is_integer:n #1
+  {
+    \fp_set:Nn \l__chemmacros_tmpa_fp { round(#1 + 1 , 0 ) - 1 }
+    \fp_compare:nNnTF { \l__chemmacros_tmpa_fp } = { #1 }
+      { \bool_set_true:N \l__chemmacros_ox_integer_bool }
+      {
+        \bool_set_false:N \l__chemmacros_ox_integer_bool
+        \bool_set_false:N \l__chemmacros_ox_format_roman_bool
+      }
+  }
+\cs_generate_variant:Nn \__chemmacros_ox_is_integer:n { V }
+
+\cs_new_protected:Npn \__chemmacros_fp_to_Roman:n #1
+  {
+    \group_begin:
+      \fp_set:Nn \l__chemmacros_tmpa_fp { round(#1 , 0 ) }
+      \int_set:Nn \l__chemmacros_tmpa_int
+        { \fp_to_tl:N \l__chemmacros_tmpa_fp } 
+      \int_compare:nTF { \l__chemmacros_tmpa_int = 0 }
+        { 0 }
+        { \int_to_Roman:n { \l__chemmacros_tmpa_int } }
+    \group_end:
+  }
+\cs_generate_variant:Nn \__chemmacros_fp_to_Roman:n { V }
+
+\cs_new_protected:Npn \__chemmacros_fp_to_arabic:n #1
+  {
+    \group_begin:
+      \fp_set:Nn \l__chemmacros_tmpa_tl { #1 }
+      \fp_to_tl:N \l__chemmacros_tmpa_tl
+    \group_end:
+  }
+\cs_generate_variant:Nn \__chemmacros_fp_to_arabic:n { V }
+
+\cs_new_protected:Npn \__chemmacros_fp_show:n #1
+  {
+    \group_begin:
+      \fp_set:Nn \l__chemmacros_tmpa_tl { #1 }
+      \bool_if:NTF \l__chemmacros_ox_decimal_marker_comma_bool
+        {
+          \tl_set:Nx \l__chemmacros_tmpb_tl
+            { \fp_to_tl:N \l__chemmacros_tmpa_tl }
+          \tl_replace_once:Nnn \l__chemmacros_tmpb_tl { . } { {,} }
+          \tl_use:N \l__chemmacros_tmpb_tl
+        }
+        { \fp_to_tl:N \l__chemmacros_tmpa_tl }
+    \group_end:
+  }
+\cs_generate_variant:Nn \__chemmacros_fp_show:n { V }
+
+\cs_new_protected:Npn \__chemmacros_ox_write:nn #1#2
+  {
+    \tl_if_blank:nT { #1 }
+      { \msg_error:nnx { chemmacros } { ox } { oxidation~number~missing } }
+    \tl_if_blank:nT { #2 }
+      { \msg_error:nnx { chemmacros } { ox } { atom~missing } }
+    \ensuremath
+      {
+        \bool_if:NT \l__chemmacros_ox_super_bool
+          {
+            \chemmacros_text:n
+              {
+                #2
+                \c_math_toggle_token
+                  \c_math_superscript_token
+                    { \text { \tiny \__chemmacros_ox_process_number:n { #1 } } }
+                \c_math_toggle_token
+              }
+          }
+        \bool_if:NT \l__chemmacros_ox_side_bool
+          {
+            \chemmacros_text:n
+              { #2 ( \text { \__chemmacros_ox_process_number:n { #1 } } ) }
+          }
+        \bool_if:NT \l__chemmacros_ox_top_bool
+          {
+            \overset
+              {
+                \bool_if:NTF \l__chemmacros_ox_align_center_bool
+                  { \clap } { \rlap }
+                {
+                  \chemmacros_text:n
+                    { \tiny \__chemmacros_ox_process_number:n { #1 } }
+                }
+              }
+              { \chemmacros_text:n { #2 } }
+          }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_top:
+  {
+    \bool_set_true:N  \l__chemmacros_ox_top_bool
+    \bool_set_false:N \l__chemmacros_ox_super_bool
+    \bool_set_false:N \l__chemmacros_ox_side_bool
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_super:
+  {
+    \bool_set_false:N \l__chemmacros_ox_top_bool
+    \bool_set_true:N  \l__chemmacros_ox_super_bool
+    \bool_set_false:N \l__chemmacros_ox_side_bool
+  }
+
+\cs_new_protected:Npn \__chemmacros_ox_pos_side:
+  {
+    \bool_set_false:N \l__chemmacros_ox_top_bool
+    \bool_set_false:N \l__chemmacros_ox_super_bool
+    \bool_set_true:N  \l__chemmacros_ox_side_bool
+  }
+
+\keys_define:nn { chemmacros / ox }
+  {
+    pos            .choice: ,
+    pos / top      .code:n     = \__chemmacros_ox_pos_top: ,
+    pos / super    .code:n     = \__chemmacros_ox_pos_super: ,
+    pos / side     .code:n     = \__chemmacros_ox_pos_side: ,
+    roman          .bool_set:N = \l__chemmacros_ox_format_roman_bool ,
+    roman          .default:n  = true ,
+    parse          .bool_set:N = \l__chemmacros_ox_parse_bool ,
+    parse          .default:n  = true ,
+    explicit-sign  .bool_set:N = \l__chemmacros_ox_explicit_sign_bool ,
+    explicit-sign  .default:n  = true ,
+    decimal-marker .choice: ,
+    decimal-marker / comma .code:n =
+      { \bool_set_true:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
+    decimal-marker / point .code:n =
+      { \bool_set_false:N \l__chemmacros_ox_decimal_marker_comma_bool } ,
+    align          .choice: ,
+    align / center .code:n    = \bool_set_true:N \l__chemmacros_ox_align_center_bool ,
+    align / right  .code:n    = \bool_set_false:N \l__chemmacros_ox_align_center_bool
+  }
+
+% \ox[<keyval>]{<num>,<atom>}
+% \ox*[<keyval>]{<num>,<atom>} => always number on the side
+\cs_new_protected:Npn \chemmacros_ox:nnnn #1#2#3#4
+  {
+    \group_begin:
+      \tl_if_blank:nF { #1 } { \__chemmacros_ox_pos_super: }
+      \keys_set:nn { chemmacros / ox } { #2 }
+      \__chemmacros_ox_write:nn { #3 } { #4 }
+    \group_end:
+  }
+
+\NewDocumentCommand \ox { s o > { \SplitArgument { 1 } { , } } m }
+  {
+    \IfBooleanTF { #1 }
+      {
+        \IfNoValueTF { #2 }
+          { \chemmacros_ox:nnnn { #1 } {    } #3 }
+          { \chemmacros_ox:nnnn { #1 } { #2 } #3 }
+      }
+      {
+        \IfNoValueTF { #2 }
+          { \chemmacros_ox:nnnn { } {    } #3 }
+          { \chemmacros_ox:nnnn { } { #2 } #3 }
+      }
+  }
+
+% --------------------------------------------------------------------------- %
+% - oxidation arrows
+\tl_new:N   \l__chemmacros_redox_begin_tl
+\tl_new:N   \l__chemmacros_redox_end_tl
+\tl_new:N   \l__chemmacros_redox_tikz_tl
+\tl_new:N   \l__chemmacros_redox_shift_tl
+\tl_new:N   \l__chemmacros_redox_anchor_tl
+\tl_new:N   \l__chemmacros_redox_side_tl
+
+\fp_new:N   \l__chemmacros_redox_shift_fp
+
+\dim_new:N  \l__chemmacros_redox_sep_dim
+\dim_new:N  \l__chemmacros_redox_sep_default_dim
+\dim_set:Nn \l__chemmacros_redox_sep_default_dim { .2em }
+\dim_new:N  \l__chemmacros_redox_dist_dim
+\dim_set:Nn \l__chemmacros_redox_dist_dim {.6em}
+
+% place and name nodes:
+% \OX{<name>,<atom>}
+\NewDocumentCommand \OX { > { \SplitArgument { 1 } { , } } m }
+  { \chemmacros_redox_partner:nn #1 }
+
+\cs_new_protected:Npn \chemmacros_redox_partner:nn #1#2
+  {
+    \chemformula_latex_if:nTF { measuring@ }
+      {
+        \group_begin:
+        \tikz[baseline=(#1.base)]
+          { \node [inner~sep=0pt] (#1) { #2 } ; }
+        \group_end:
+      }
+      {
+        \tl_if_blank:nT { #1 }
+          { \msg_error:nnx { chemmacros } { OX } { node~name~missing } }
+        \tl_if_blank:nT { #2 }
+          { \msg_error:nnx { chemmacros } { OX } { atom~missing } }
+        \tikz[baseline=(#1.base),remember~picture]
+          { \node [inner~sep=0pt] (#1) { #2 } ; }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_redox_coordinates:nn #1#2
+  {
+    \tl_set:Nn \l__chemmacros_redox_begin_tl { #1 }
+    \tl_set:Nn \l__chemmacros_redox_end_tl   { #2 }
+  }
+
+\cs_new_protected:Npn \chemmacros_redox:nnnnn #1#2#3#4#5
+  {
+    \tl_clear:N \l__chemmacros_redox_begin_tl
+    \tl_clear:N \l__chemmacros_redox_end_tl
+    \tl_clear:N \l__chemmacros_redox_tikz_tl
+    \__chemmacros_redox_coordinates:nn { #1 } { #2 }
+    \tl_if_blank:nF { #3 }
+      { \tl_set:Nn \l__chemmacros_redox_tikz_tl { #3 } }
+    \tl_if_blank:nTF { #4 }
+      {
+        \fp_set:Nn \l__chemmacros_redox_shift_fp  { 1 }
+        \tl_set:Nn \l__chemmacros_redox_anchor_tl { above }
+        \tl_set:Nn \l__chemmacros_redox_side_tl { north }
+        \dim_set_eq:NN
+          \l__chemmacros_redox_sep_dim
+          \l__chemmacros_redox_sep_default_dim
+      }
+      {
+        \fp_compare:nNnTF { #4 } < { 0 }
+          {
+            \tl_set:Nn \l__chemmacros_redox_anchor_tl { below }
+            \tl_set:Nn \l__chemmacros_redox_side_tl { south }
+            \exp_args:NNo \dim_set:Nn \l__chemmacros_redox_sep_dim
+              { - \l__chemmacros_redox_sep_default_dim }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_redox_anchor_tl { above }
+            \tl_set:Nn \l__chemmacros_redox_side_tl { north }
+            \dim_set_eq:NN
+              \l__chemmacros_redox_sep_dim
+              \l__chemmacros_redox_sep_default_dim
+          }
+        \fp_set:Nn \l__chemmacros_redox_shift_fp { #4 }
+      }
+      \tl_set:Nn \l__chemmacros_redox_shift_tl
+        { \fp_to_tl:N \l__chemmacros_redox_shift_fp }
+    \tikz[remember~picture,overlay]
+      {
+        \chemmacros_tikz_draw:f { \tl_use:N \l__chemmacros_redox_tikz_tl }
+        ($
+          (\l__chemmacros_redox_begin_tl .
+          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
+        $)
+        -- 
+        ++(0,\l__chemmacros_redox_shift_tl * \l__chemmacros_redox_dist_dim) -|
+        node [pos=.25,\l__chemmacros_redox_anchor_tl] { { #5 } }
+        ($
+          (\l__chemmacros_redox_end_tl .
+          \l__chemmacros_redox_side_tl)+(0,\l__chemmacros_redox_sep_dim)
+        $) ;
+      }
+  }
+
+\NewDocumentCommand \redox { > { \SplitArgument { 1 } { , } } r() o o G{} }
+  {
+    \IfNoValueT { #1 }
+      {
+        \msg_error:nnx { chemmacros } { redox }
+          { You~need~to~specify~coordinates }
+      }
+    \IfNoValueTF { #2 }
+      { \chemmacros_redox:nnnnn #1 { } { } { #4 } }
+      {
+        \IfNoValueTF { #3 }
+          { \chemmacros_redox:nnnnn #1 { #2 } {    } { #4 } }
+          { \chemmacros_redox:nnnnn #1 { #2 } { #3 } { #4 } }
+      }
+  }
+
+% redox-keys
+\keys_define:nn { chemmacros / redox }
+  {
+    dist .dim_set:N = \l__chemmacros_redox_dist_dim ,
+    dist .default:n = { .6em } ,
+    sep  .dim_set:N = \l__chemmacros_redox_sep_default_dim ,
+    sep  .default:n = { .2em }
+  }
+
+% --------------------------------------------------------------------------- %
+% spectroscopy
+\tl_new:N  \g__chemmacros_nmr_isotope_tl
+\tl_new:N  \l__chemmacros_nmr_isotope_default_tl
+\tl_set:Nn \l__chemmacros_nmr_isotope_default_tl { 1 }
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_pre_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_pre_tl { ( }
+\tl_new:N  \l__chemmacros_nmr_coupling_nuclei_post_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_post_tl { ) }
+\tl_new:N  \l__chemmacros_nmr_coupling_bonds_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_bonds_pre_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_pre_tl { }
+\tl_set:Nn \l__chemmacros_nmr_coupling_bonds_post_tl { \! }
+\tl_new:N  \l__chemmacros_nmr_coupling_symbol_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_symbol_tl { J }
+\tl_new:N  \g__chemmacros_nmr_element_coupled_tl
+\tl_new:N  \g__chemmacros_nmr_element_tl
+\tl_new:N  \l__chemmacros_nmr_element_default_tl
+\tl_set:Nn \l__chemmacros_nmr_element_default_tl { H }
+\tl_new:N  \l__chemmacros_nmr_format_tl
+\tl_new:N  \l__chemmacros_nmr_delta_tl
+\tl_new:N  \l__chemmacros_nmr_coupling_unit_tl
+\tl_set:Nn \l__chemmacros_nmr_coupling_unit_tl { \hertz }
+\tl_new:N  \l__chemmacros_nmr_unit_tl
+\tl_set:Nn \l__chemmacros_nmr_unit_tl { \mega\hertz }
+\tl_new:N  \l__chemmacros_nmr_list_setup_tl
+\tl_set:Nn \l__chemmacros_nmr_list_setup_tl
+  {
+    \topsep\z@skip \partopsep\z@skip 
+    \itemsep\z@ \parsep\z@ \itemindent\z@
+    \leftmargin\z@
+  }
+\tl_new:N  \l__chemmacros_nmr_position_tl
+\tl_new:N  \l__chemmacros_nmr_element_method_connector_tl
+\tl_set:Nn \l__chemmacros_nmr_element_method_connector_tl {-}
+\tl_new:N  \l__chemmacros_nmr_method_tl
+\tl_set:Nn \l__chemmacros_nmr_method_tl {NMR}
+
+\bool_new:N      \l__chemmacros_nmr_coupling_nuclei_sub_bool
+\bool_new:N      \l__chemmacros_nmr_frequency_bool
+\bool_new:N      \l__chemmacros_nmr_solvent_bool
+\bool_new:N      \l__chemmacros_nmr_delimiters_bool
+\bool_new:N      \l__chemmacros_nmr_comma_bool
+\bool_new:N      \l__chemmacros_nmr_inner_bool
+\bool_new:N      \l__chemmacros_nmr_position_side_bool
+\bool_new:N      \l__chemmacros_nmr_parse_bool
+\bool_set_true:N \l__chemmacros_nmr_parse_bool
+\bool_new:N      \l__chemmacros_nmr_list_bool
+\bool_new:N      \l__chemmacros_nmr_use_equal_bool
+\bool_new:N      \l__chemmacros_nmr_custom_command_active_bool
+\bool_new:N      \l__chemmacros_nmr_custom_command_used_bool
+
+\cs_new_protected:Npn \__chemmacros_nmr_nucleus:nn #1#2
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl { #1 }
+    \tl_if_in:nnTF { #2 } { [ }
+      { \__chemmacros_nmr_element:w #2 \q_stop }
+      {
+        \tl_gset:No \g__chemmacros_nmr_element_tl { #2 }
+        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
+      }
+  }
+\cs_generate_variant:Nn \__chemmacros_nmr_nucleus:nn { VV }
+
+\cs_new_protected:Npn \__chemmacros_nmr_nucleus:w #1,#2 \q_stop
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_isotope_tl { #1 }
+    \tl_if_in:nnTF { #2 } { [ }
+      { \__chemmacros_nmr_element:w #2 \q_stop }
+      {
+        \tl_gset:No \g__chemmacros_nmr_element_tl { #2 }
+        \tl_gclear:N \g__chemmacros_nmr_element_coupled_tl
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_element:w #1[#2] \q_stop
+  {
+    \tl_gset:Nn \g__chemmacros_nmr_element_tl { #1 }
+    \tl_gset:Nn \g__chemmacros_nmr_element_coupled_tl { #2 }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_default_nucleus:w #1,#2 \q_stop
+  {
+    \tl_set:Nn \l__chemmacros_nmr_isotope_default_tl { #1 }
+    \tl_set:Nn \l__chemmacros_nmr_element_default_tl { #2 }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_base:nn #1#2
+  {
+    \tl_if_blank:VF \g__chemmacros_nmr_element_coupled_tl
+      {
+        \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl { \{ }
+        \tl_put_right:Nn \g__chemmacros_nmr_element_coupled_tl { \} }
+      }
+    \tl_put_left:Nn \g__chemmacros_nmr_element_coupled_tl { #2 }
+    \iupac { ^ { #1 } }
+    \bool_if:NTF \l__chemmacros_nmr_parse_bool
+      { \chemformula_ch:nV {} \g__chemmacros_nmr_element_coupled_tl }
+      { \chemmacros_atom:V \g__chemmacros_nmr_element_coupled_tl }
+    \tl_use:N \l__chemmacros_nmr_element_method_connector_tl
+    \tl_use:N \l__chemmacros_nmr_method_tl
+  }
+\cs_generate_variant:Nn \__chemmacros_nmr_base:nn { VV }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency:n #1
+  {
+    \tl_if_in:nnTF { #1 } { , }
+      { \__chemmacros_nmr_frequency_aux_i:w #1 \q_stop }
+      { \__chemmacros_nmr_frequency_aux_ii:n { #1 } }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_i:w #1,#2 \q_stop
+  { \SI { #1 } { #2 } }
+
+\cs_new_protected:Npn \__chemmacros_nmr_frequency_aux_ii:n #1
+  { \SI { #1 } { \tl_use:N \l__chemmacros_nmr_unit_tl } }
+
+\cs_new_eq:NN \__chemmacros_nmr_number:n \use:n
+\cs_new_eq:NN \__chemmacros_nmr_position:n \use:n
+
+\keys_define:nn { chemmacros / nmr }
+  {
+    unit          .tl_set:N      = \l__chemmacros_nmr_unit_tl ,
+    unit          .default:n     = \mega\hertz ,
+    nucleus       .code:n        =
+      { \__chemmacros_nmr_default_nucleus:w #1 \q_stop } ,
+    nucleus       .default:n     = { 1,H } ,
+    format        .tl_set:N      = \l__chemmacros_nmr_format_tl ,
+    method        .tl_set:N      = \l__chemmacros_nmr_method_tl ,
+    connector     .tl_set:N      = \l__chemmacros_nmr_element_method_connector_tl ,
+    pos-number    .choice: ,
+    pos-number / sub  .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl { _ }
+      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
+    pos-number / super .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl { ^ }
+      \bool_set_false:N \l__chemmacros_nmr_position_side_bool ,
+    pos-number / side .code:n =
+      \tl_set:Nn \l__chemmacros_nmr_position_tl { - }
+      \bool_set_true:N \l__chemmacros_nmr_position_side_bool ,
+    coupling-unit .tl_set:N   = \l__chemmacros_nmr_coupling_unit_tl ,
+    coupling-pos  .choice: ,
+    coupling-pos / sub .code:n =
+      \bool_set_true:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
+    coupling-pos / side .code:n =
+      \bool_set_false:N \l__chemmacros_nmr_coupling_nuclei_sub_bool ,
+    coupling-nuclei-pre  .tl_set:N =
+      \l__chemmacros_nmr_coupling_nuclei_pre_tl ,
+    coupling-nuclei-post .tl_set:N =
+      \l__chemmacros_nmr_coupling_nuclei_post_tl ,
+    coupling-bonds-pre   .tl_set:N =
+      \l__chemmacros_nmr_coupling_bonds_pre_tl ,
+    coupling-bonds-post  .tl_set:N =
+      \l__chemmacros_nmr_coupling_bonds_post_tl ,
+    coupling-symbol .tl_set:N    =
+      \l__chemmacros_nmr_coupling_symbol_tl ,
+    atom-number-cs .code:n       =
+      \cs_set_eq:NN \__chemmacros_nmr_number:n #1 ,
+    coupling-pos-cs .code:n      =
+      \cs_set_eq:NN \__chemmacros_nmr_position:n #1 ,
+    parse         .bool_set:N    = \l__chemmacros_nmr_parse_bool ,
+    delta         .code:n        =
+      \tl_set:Nn \l__chemmacros_nmr_delta_tl { \, #1 } ,
+    list          .bool_set:N    = \l__chemmacros_nmr_list_bool ,
+    list          .default:n     = true ,
+    list-setup    .tl_set:N      = \l__chemmacros_nmr_list_setup_tl ,
+    use-equal     .bool_set:N    = \l__chemmacros_nmr_use_equal_bool ,
+    use-equal     .default:n     = true
+  }
+
+\prop_new:N \l__chemmacros_nmr_prop
+
+\cs_new_protected:Npn \chemmacros_new_nmr:Nn #1#2
+  {
+    \bool_if:nTF
+      {
+        \prop_if_in_p:Nn \l__chemmacros_nmr_prop { #1 }
+        ||
+        \cs_if_exist_p:N #1
+      }
+      { \msg_error:nnn { chemmacros } { new-nmr } { #1 } }
+      {
+        \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
+        \NewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_define_nmr:Nn #1#2
+  {
+    \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
+    \cs_if_exist:NTF #1
+      {
+        \RenewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+      {
+        \NewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_nmr:Nn #1#2
+  {
+    \bool_if:nTF
+      {
+        \prop_if_in_p:Nn \l__chemmacros_nmr_prop { #1 }
+        &&
+        \cs_if_exist_p:N #1
+      }
+      {
+        \prop_put:Nnn \l__chemmacros_nmr_prop { #1 } { #2 }
+        \RenewDocumentCommand #1 { s }
+          { \IfBooleanTF {##1} { \NMR*{#2} } { \NMR{#2} } }
+      }
+      { \msg_error:nnn { chemmacros } { renew-nmr } { #1 } }
+  }
+
+\NewDocumentCommand \NewChemNMR { mm }
+  { \chemmacros_new_nmr:Nn #1 { #2 } }
+
+\NewDocumentCommand \RenewChemNMR { mm }
+  { \chemmacros_renew_nmr:Nn #1 { #2 } }
+
+\NewDocumentCommand \DeclareChemNMR { mm }
+  { \chemmacros_define_nmr:Nn #1 { #2 } }
+
+\NewDocumentCommand \NMR { s G{} D(){} O{} }
+  {
+    \IfBooleanTF { #1 }
+      { \chemmacros_nmr:nnnn { * } { #2 } { #3 } { #4 } }
+      { \chemmacros_nmr:nnnn {   } { #2 } { #3 } { #4 } }
+  }
+
+\AtBeginDocument
+  {
+    % \NMR{<num>,<elem>}(<num>,<unit>)[<solvent>] ALL arguments are optional
+    % \NMR* same but without ": $\delta$" at end
+    \cs_new_protected:Npn \chemmacros_nmr:nnnn #1#2#3#4
+      {
+        \bool_if:NT \l__chemmacros_nmr_list_bool { \item \scan_stop: }
+        \group_begin:
+          \chemmacros_leave_vmode:
+          \bool_set_false:N \l__chemmacros_nmr_frequency_bool
+          \bool_set_false:N \l__chemmacros_nmr_solvent_bool
+          \tl_if_empty:nF { #3 }
+            { \bool_set_true:N \l__chemmacros_nmr_frequency_bool }
+          \tl_if_empty:nF { #4 }
+            { \bool_set_true:N \l__chemmacros_nmr_solvent_bool }
+          \bool_if:nT
+            {
+              \l__chemmacros_nmr_frequency_bool
+              ||
+              \l__chemmacros_nmr_solvent_bool
+            }
+            { \bool_set_true:N \l__chemmacros_nmr_delimiters_bool }
+          \bool_if:nT
+            {
+              \l__chemmacros_nmr_frequency_bool
+              &&
+              \l__chemmacros_nmr_solvent_bool
+            }
+            { \bool_set_true:N \l__chemmacros_nmr_comma_bool }
+          \tl_if_empty:nTF { #2 }
+            {
+              \__chemmacros_nmr_nucleus:VV
+                \l__chemmacros_nmr_isotope_default_tl
+                \l__chemmacros_nmr_element_default_tl
+            }
+            { \__chemmacros_nmr_nucleus:w #2 \q_stop }
+          \mode_if_math:TF
+            {
+              \text
+                {
+                  \group_begin:
+                    \tl_use:N \l__chemmacros_nmr_format_tl
+                    \__chemmacros_nmr_base:VV
+                      \g__chemmacros_nmr_isotope_tl
+                      \g__chemmacros_nmr_element_tl
+                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                      { ~ ( }
+                    \bool_if:NT \l__chemmacros_nmr_frequency_bool
+                      { \__chemmacros_nmr_frequency:n { #3 } }
+                    \bool_if:NT \l__chemmacros_nmr_comma_bool
+                      { , ~ }
+                    \bool_if:NT \l__chemmacros_nmr_solvent_bool
+                      { \chemmacros_atom:n { #4 } }
+                    \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                      { ) }
+                    \tl_if_blank:nT { #1 } { : ~ }
+                  \group_end:
+                }
+              \tl_if_blank:nT { #1 }
+                {
+                  \delta
+                  \text { \l__chemmacros_nmr_delta_tl }
+                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool { = }
+                }
+            }
+            {
+              \group_begin:
+                \tl_use:N \l__chemmacros_nmr_format_tl
+                \__chemmacros_nmr_base:VV
+                  \g__chemmacros_nmr_isotope_tl
+                  \g__chemmacros_nmr_element_tl
+                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                  { ~ ( }
+                \bool_if:NT \l__chemmacros_nmr_frequency_bool
+                  { \__chemmacros_nmr_frequency:n { #3 } }
+                \bool_if:NT \l__chemmacros_nmr_comma_bool
+                  { , ~ }
+                \bool_if:NT \l__chemmacros_nmr_solvent_bool
+                  {
+                    \bool_if:NTF \l__chemmacros_nmr_parse_bool
+                      { \chemformula_ch:nn { } { #4 } }
+                      { #4 }
+                  }
+                \bool_if:NT \l__chemmacros_nmr_delimiters_bool
+                  { ) }
+                \tl_if_blank:nT { #1 } { : }
+              \group_end:
+              \tl_if_blank:nT { #1 }
+                {
+                  \tl_use:N \c_space_tl
+                  \c_math_toggle_token
+                    \delta
+                  \c_math_toggle_token
+                  \l__chemmacros_nmr_delta_tl
+                  \bool_if:NT \l__chemmacros_nmr_use_equal_bool { ~ = }
+                }
+              \bool_if:NF \l__chemmacros_nmr_comma_bool
+                { \tl_if_blank:nT { #1 } { \chemmacros_xspace: } }
+            }
+        \group_end:
+      }
+  }
+
+\NewDocumentCommand \chemmacros_data:w { smo }
+  {
+    \bool_if:NT \l__chemmacros_nmr_list_bool { \item }
+    {
+      \tl_use:N \l__chemmacros_nmr_format_tl #2
+      \IfNoValueF { #3 } { ~ ( #3 ) }
+      \IfBooleanT { #1 } { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { : } }
+    }
+    \IfBooleanF { #1 } { \bool_if:NT \l__chemmacros_nmr_use_equal_bool { ~ = } }
+  }
+
+\cs_new_protected:Npn \chemmacros_val:n #1
+  {
+    \tl_if_in:nnTF { #1 } { -- }
+      { \chemmacros_val_aux:w #1 \q_nil }
+      { \num { #1 } }
+  }
+
+\cs_new_protected:Npn \chemmacros_val_aux:w #1--#2 \q_nil
+  { \numrange { #1 } { #2 } }
+
+\NewDocumentEnvironment { experimental } { o }
+  {
+    \group_begin:
+    \IfNoValueF { #1 } { \keys_set:nn { chemmacros / nmr } { #1 } }
+    \bool_set_true:N \l__chemmacros_nmr_inner_bool
+    \cs_set_eq:NN \#    \chemmacros_nmr_number:n
+    \cs_set_eq:NN \pos  \chemmacros_nmr_position:n
+    \cs_set_eq:NN \J    \chemmacros_nmr_coupling:w
+    \cs_set_eq:NN \data \chemmacros_data:w
+    \cs_set_eq:NN \val  \chemmacros_val:n
+    \bool_if:NT \l__chemmacros_nmr_list_bool
+      { \list {} { \l__chemmacros_nmr_list_setup_tl } }
+  }
+  {
+    \bool_if:NT \l__chemmacros_nmr_list_bool
+      { \endlist }
+    \group_end:
+    \chemmacros_ignore_spaces:
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_number:n #1
+  {
+    \__chemmacros_nmr_number:n { #1 } \,
+    \chemmacros_atom:V \g__chemmacros_nmr_element_tl
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_position:n #1
+  {
+    \chemmacros_chemformula:x
+      {
+        \exp_not:V \g__chemmacros_nmr_element_tl
+        \bool_if:NF \l__chemmacros_nmr_position_side_bool
+          {
+            \exp_not:V \l__chemmacros_nmr_position_tl
+            \exp_not:n { {#1} }
+          }
+      }
+    \bool_if:NT \l__chemmacros_nmr_position_side_bool
+      {
+        \tl_use:N \l__chemmacros_nmr_position_tl
+        \__chemmacros_nmr_position:n { #1 }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_nmr_coupling:w
+  {
+    \tl_clear:N \l__chemmacros_nmr_coupling_nuclei_tl
+    \tl_clear:N \l__chemmacros_nmr_coupling_bonds_tl
+    \peek_meaning:NTF (
+      { \__chemmacros_nmr_coupling:w }
+      { \__chemmacros_nmr_coupling_aux_i:w }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling:w (#1;#2)
+  {
+    \tl_set:Nn \l__chemmacros_nmr_coupling_bonds_tl
+      {
+        \l__chemmacros_nmr_coupling_bonds_pre_tl
+        #1
+        \l__chemmacros_nmr_coupling_bonds_post_tl
+      }
+    \bool_if:NTF \l__chemmacros_nmr_coupling_nuclei_sub_bool
+      {
+        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
+          {
+            \c_math_subscript_token
+              { \chemmacros_chemformula:n {#2} }
+          }
+      }
+      {
+        \tl_set:Nn \l__chemmacros_nmr_coupling_nuclei_tl
+          {
+            \l__chemmacros_nmr_coupling_nuclei_pre_tl
+            \chemmacros_chemformula:n {#2}
+            \l__chemmacros_nmr_coupling_nuclei_post_tl
+          }
+      }
+    \__chemmacros_nmr_coupling_aux_i:w
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_i:w
+  {
+    \peek_meaning:NTF [
+      { \__chemmacros_nmr_coupling_aux_ii:w }
+      { \__chemmacros_nmr_coupling_aux_iii:n }
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_ii:w [#1]#2
+  {
+    \group_begin:
+      \sisetup
+        {
+          list-final-separator={,~},
+          list-pair-separator={,~},
+          list-units=single
+        }
+      \c_math_toggle_token
+        ^{ \l__chemmacros_nmr_coupling_bonds_tl }
+        \l__chemmacros_nmr_coupling_symbol_tl
+        \l__chemmacros_nmr_coupling_nuclei_tl = \SIlist{#2}{#1}
+      \c_math_toggle_token
+    \group_end:
+  }
+
+\cs_new_protected:Npn \__chemmacros_nmr_coupling_aux_iii:n #1
+  {
+    \group_begin:
+      \sisetup
+        {
+          list-final-separator={,~},
+          list-pair-separator={,~},
+          list-units=single
+        }
+      \c_math_toggle_token
+         ^{ \l__chemmacros_nmr_coupling_bonds_tl }
+         \l__chemmacros_nmr_coupling_symbol_tl
+         \l__chemmacros_nmr_coupling_nuclei_tl
+         = \exp_args:Nno \SIlist { #1 } { \l__chemmacros_nmr_coupling_unit_tl }
+      \c_math_toggle_token
+    \group_end:
+  }
+
+% --------------------------------------------------------------------------
+% deprecated mhName:
+\keys_define:nn { chemmacros }
+  { mhName .code:n = \chemmacros_option_deprecated:n { mhName } }
+
+% --------------------------------------------------------------------------- %
+% - phases
+\bool_new:N \l__chemmacros_phases_sub_bool
+\dim_new:N  \l__chemmacros_phases_space_dim
+\dim_set:Nn \l__chemmacros_phases_space_dim { .1333 em }
+\prop_new:N \l__chemmacros_phases_prop
+\prop_new:N \l__chemmacros_phases_german_prop
+
+\keys_define:nn { chemmacros / phases }
+  {
+    pos        .choice: ,
+    pos / sub  .code:n    = \bool_set_true:N \l__chemmacros_phases_sub_bool ,
+    pos / side .code:n    = \bool_set_false:N \l__chemmacros_phases_sub_bool ,
+    space      .dim_set:N = \l__chemmacros_phases_space_dim
+  }
+
+\cs_new_protected:Npn \chemmacros_new_phase:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \cs_if_free:NF #1
+      { \msg_error:nnn {chemmacros} {new-phase} {#1} }
+    \exp_args:Nx \@trnslt@declare@translation
+      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
+    \__chemmacros_define_phase:Nx #1
+      {
+        \exp_not:N \chemmacros_translate:n
+          { phase-\l__chemmacros_tmpa_tl }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_define_phase:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \exp_args:Nx \@trnslt@declare@translation
+      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
+    \__chemmacros_define_phase:Nx #1
+      {
+        \exp_not:N \chemmacros_translate:n
+          { phase-\l__chemmacros_tmpa_tl }
+      }
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_phase:Nn #1#2
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl
+      { \chemmacros_remove_backslash:N #1 }
+    \cs_if_exist:NF #1
+      { \msg_error:nnn {chemmacros} {renew-phase} {#1} }
+    \exp_args:Nx \@trnslt@declare@translation
+      { phase-\l__chemmacros_tmpa_tl } {fallback} {#2}
+    \__chemmacros_define_phase:Nx #1
+      {
+        \exp_not:N \chemmacros_translate:n
+          { phase-\l__chemmacros_tmpa_tl }
+      }
+  }
+
+\NewDocumentCommand \NewChemPhase { mom }
+  { \chemmacros_new_phase:Nn #1 {#3} }
+
+\NewDocumentCommand \DeclareChemPhase { mom }
+  { \chemmacros_define_phase:Nn #1 {#3} }
+
+\NewDocumentCommand \RenewChemPhase { mom }
+  { \chemmacros_renew_phase:Nn #1 {#3} }
+
+\cs_new_protected:Npn \__chemmacros_define_phase:Nn #1#2
+  {
+    \cs_if_exist:NF #1 { \cs_new:Npn #1 {} }
+    \DeclareDocumentCommand #1 { o }
+      {
+        \bool_if:NTF \l__chemmacros_phases_sub_bool
+          {
+            \bool_if:NTF \l_chemformula_inside_ch_bool
+              { \chemformula_subscript:n { ( #2 \IfNoValueF {##1} {,~##1} ) } }
+              {
+                \ensuremath
+                  {
+                    \c_math_subscript_token
+                    { \text { ( #2 \IfNoValueF {##1} {,~##1} ) } }
+                  }
+              }
+          }
+          {
+            \ensuremath
+              {
+                \skip_horizontal:N \l__chemmacros_phases_space_dim
+                \text { ( #2 \IfNoValueF {##1} {,~##1} ) }
+              }
+          }
+      }
+  }
+\cs_generate_variant:Nn \__chemmacros_define_phase:Nn { Nx }
+
+\NewChemPhase \sld {s}
+\NewChemPhase \lqd {l}
+\NewChemPhase \gas {g}
+\NewChemPhase \aq  {aq}
+
+\cs_new_protected:Npn \chemmacros_phase:n #1
+  {
+    \bool_if:NTF \l__chemmacros_phases_sub_bool
+      { \ensuremath { \c_math_subscript_token { \text { (#1) } } } }
+      {
+        \ensuremath
+          {
+            \skip_horizontal:N \l__chemmacros_phases_space_dim
+            \text { (#1) }
+          }
+      }
+  }
+
+\NewDocumentCommand \phase { m }
+  { \chemmacros_phase:n {#1} }
+
+% --------------------------------------------------------------------------
+% reaction environments
+\cs_new_protected:Npn \__chemmacros_record_for_lor:nnnnn #1#2#3#4#5
+  {
+    \tl_if_eq:nnT { #1 } { reaction }
+      {
+        \group_begin:
+          % we need to prevent \Hy@make@anchor from being written to the lor
+          % file:
+          \bool_if:NT \l__chemmacros_hyperref_bool
+            { \cs_set:Npn \Hy@make@anchor {} }
+          \addcontentsline { lor } { reaction }
+            {
+              \tl_use:N \l__chemmacros_reaction_lorname_tl
+              \tl_use:N \c_space_tl
+              #2 #3 #4 #5
+              \tl_use:N \g__chemmacros_reaction_description_tl
+            }
+          \tl_gclear:N \g__chemmacros_reaction_description_tl
+        \group_end:
+      }
+  }
+
+% redefine mathtools' command \MT_define_tagform:nwnn to ensure we add an
+% entry to the list of reactions even if the user redefines the reaction tag
+% this should probably be done via patching...
+\AfterPackage* { mathtools }
+  {
+    \cs_set_protected:Npn \MT_define_tagform:nwnn #1[#2]#3#4
+      {
+        \@namedef{MT_tagform_#1:n}##1
+          {
+            % this is the original part:
+            \maketag@@@{#3\ignorespaces#2{##1}\unskip\@@italiccorr#4}
+            % this is added => this disturbs hyperref:
+            \__chemmacros_record_for_lor:nnnnn
+              { #1 } { #3 } { #2 } { ##1 } { #4 }
+          }
+      }
+  }
+
+\tl_new:N \g__chemmacros_reaction_description_tl
+
+\cs_new_protected:Npn \chemmacros_add_reaction_description:n #1
+  {
+    \tl_if_blank:nF { #1 }
+      { \tl_gset:Nn \g__chemmacros_reaction_description_tl { : ~ #1 } }
+  }
+
+\NewDocumentCommand \AddRxnDesc { m }
+  { \chemmacros_add_reaction_description:n { #1 } }
+
+% define \listofreactions
+\tl_new:N \l__chemmacros_reaction_lorname_tl
+\tl_new:N \reactionlistname
+\tl_new:N \l__chemmacros_reaction_heading_tl
+
+\cs_new:Npn \__chemmacros_reaction_heading:n #1
+  { \l__chemmacros_reaction_heading_tl { #1 } }
+\cs_generate_variant:Nn \__chemmacros_reaction_heading:n { V }
+
+\cs_new_protected:Npn \listofreactions
+  {
+    \__chemmacros_reaction_heading:V \reactionlistname
+    \@starttoc { lor }
+  }
+
+\cs_new_protected:Npn \l@reaction #1#2
+  { \@dottedtocline { 1 } { 1.5em } { 2.3em } { #1 } { #2 } }
+
+% create tagform
+\newtagform { reaction } { \{ } { \} }
+\newcounter { chemmacros_save_reaction }
+\newcounter { reaction }
+
+% switch to reaction tags
+\cs_new_protected:Npn \__chemmacros_begin_reaction:
+  {
+    % create individual names for `hyperref':
+    \bool_if:NT \l__chemmacros_hyperref_bool
+      {
+        \cs_set:Npn \theHequation
+          { R . \theHsection . \arabic { reaction } }
+      }
+    % enable labelformat `reaction':
+    \bool_if:NT \l__chemmacros_varioref_bool
+      { \cs_set_eq:NN \p@equation \p@reaction }
+    \setcounter { chemmacros_save_reaction } { \value { equation } }
+    \setcounter { equation } { \value { reaction } }
+    \usetagform { reaction }
+  }
+
+% switch back to equation tags
+\cs_new_protected:Npn \__chemmacros_end_reaction:
+  {
+    \setcounter { reaction } { \value { equation } }
+    \setcounter { equation } { \value { chemmacros_save_reaction } }
+  }
+
+% --------------------------------------------------------------------------- %
+\bool_new:N \l__chemmacros_reactions_star_bool
+\bool_new:N \l__chemmacros_reactions_args_bool
+
+\keys_define:nn { chemmacros / reaction }
+  {
+    star         .bool_set:N = \l__chemmacros_reactions_star_bool ,
+    star         .default:n  = true ,
+    arg          .bool_set:N = \l__chemmacros_reactions_args_bool ,
+    arg          .default:n  = true ,
+    list-name    .tl_set:N   = \reactionlistname ,
+    list-entry   .code:n     =
+      \tl_set:Nn \l__chemmacros_reaction_lorname_tl { #1 } ,
+    list-heading .tl_set:N   = \l__chemmacros_reaction_heading_tl
+  }
+
+% \DeclareChemReaction[<keyval>]{<name>}{<type>}
+\cs_new_protected:Npn \__chemmacros_define_reaction:Nnnn #1#2#3#4
+  {
+    \bool_set_false:N \l__chemmacros_reactions_star_bool
+    \bool_set_false:N \l__chemmacros_reactions_args_bool
+    \keys_set:nn { chemmacros / reaction } { #2 }
+    \bool_if:NTF \l__chemmacros_reactions_args_bool
+      {
+        #1 { #3 } [ 2 ] []
+          {
+            \__chemmacros_begin_reaction:
+            \AddRxnDesc { ##1 }
+            \begin { #4 } { ##2 }
+              \chemmacros_equation_chemformula:V \BODY
+            \end{ #4 }
+            \__chemmacros_end_reaction:
+          }
+        \bool_if:NT \l__chemmacros_reactions_star_bool
+          {
+            #1 { #3* } [ 1 ]
+              {
+                \begin { #4* } { ##1 }
+                  \chemmacros_equation_chemformula:V \BODY
+                \end { #4* }
+              }
+          }
+      }
+      {
+        #1 { #3 } [ 1 ] []
+          {
+            \__chemmacros_begin_reaction:
+            \AddRxnDesc { ##1 }
+            \begin { #4 }
+              \chemmacros_equation_chemformula:V \BODY
+            \end { #4 }
+            \__chemmacros_end_reaction:
+          }
+        \bool_if:NT \l__chemmacros_reactions_star_bool
+          {
+            #1 { #3* }
+              {
+                \begin { #4* }
+                  \chemmacros_equation_chemformula:V \BODY
+                \end { #4* }
+              }
+          }
+      }
+    \ignorespaces
+  }
+
+\cs_new_protected:Npn \chemmacros_define_reaction:nnn #1#2#3
+  {
+    \cs_if_exist:cTF { #2 }
+      { \__chemmacros_define_reaction:Nnnn \RenewEnviron { #1 } { #2 } { #3 } }
+      { \__chemmacros_define_reaction:Nnnn \NewEnviron { #1 } { #2 } { #3 } }
+  }
+
+\cs_new_protected:Npn \chemmacros_new_reaction:nnn #1#2#3
+  {
+    \cs_if_exist:cTF { #2 }
+      { \msg_error:nnx { chemmacros } { already-defined } { #2 } }
+      { \__chemmacros_define_reaction:Nnnn \NewEnviron { #1 } { #2 } { #3 } }
+  }
+
+\cs_new_protected:Npn \chemmacros_renew_reaction:nnn #1#2#3
+  {
+    \cs_if_exist:cTF { #2 }
+      { \__chemmacros_define_reaction:Nnnn \RenewEnviron { #1 } { #2 } { #3 } }
+      { \msg_error:nnx { chemmacros } { not-defined } { #2 } }
+  }
+
+\NewDocumentCommand \NewChemReaction { O{} m m }
+  { \chemmacros_new_reaction:nnn { #1 } { #2 } { #3 } }
+\NewDocumentCommand \RenewChemReaction { O{} m m }
+  { \chemmacros_renew_reaction:nnn { #1 } { #2 } { #3 } }
+\NewDocumentCommand \DeclareChemReaction { O{} m m }
+  { \chemmacros_declare_reaction:nnn { #1 } { #2 } { #3 } }
+\DeclareChemDeprecated \newreaction \NewChemReaction
+
+\cs_new_protected:Npn \chemmacros_equation_chemformula:n #1
+  { \chemformula_ch:nn { } { #1 } }
+\cs_generate_variant:Nn \chemmacros_equation_chemformula:n { V }
+
+% predefined:
+\NewChemReaction [ star ] { reaction }  { equation }
+\NewChemReaction [ star ] { reactions } { align }
+
+% --------------------------------------------------------------------------
+% thermodynamics et.al.
+% \standardstate as defined by the chemstyle package. Thanks to Joseph Wright
+% the `chemstyle' provides it with \providecommand so it doesn't matter which
+% package defines it first
+\ProvideDocumentCommand \standardstate {}
+  { { \ensuremath { \chemmacros_standardstate: } } }
+
+\cs_new_protected:Npn \chemmacros_standardstate:
+  { \mathpalette \chemmacros_standardstate_aux: \circ }
+
+\cs_new_protected:Npn \chemmacros_standardstate_aux: #1#2
+  {
+    \ooalign
+      {
+        \tex_hfil:D
+        \c_math_toggle_token #1- \c_math_toggle_token
+        \tex_hfil:D
+        \tex_cr:D
+        \tex_hfil:D
+        \c_math_toggle_token #1#2 \c_math_toggle_token
+        \tex_hfil:D
+        \tex_cr:D
+      }
+  }
+
+\cs_new_protected:Npn \changestate
+  { \mathop{} \! \chemDelta }
+
+% --------------------------------------------------------------------------
+% \State
+\tl_new:N  \l__chemmacros_State_delta_tl
+\tl_set:Nn \l__chemmacros_State_delta_tl { \changestate }
+\tl_new:N  \l__chemmacros_State_exponent_tl
+\tl_set:Nn \l__chemmacros_State_exponent_tl { \standardstate }
+
+\bool_new:N      \l__chemmacros_State_delta_bool
+\bool_set_true:N \l__chemmacros_State_delta_bool
+\bool_new:N      \l__chemmacros_State_subscript_left_bool
+\bool_set_true:N \l__chemmacros_State_subscript_left_bool
+\bool_new:N      \l__chemmacros_State_exponent_bool
+\bool_set_true:N \l__chemmacros_State_exponent_bool
+
+\keys_define:nn { chemmacros / state }
+  {
+    delta     .code:n     =
+      {
+        \exp_args:Nf \tl_if_eq:nnTF { #1 } { false }
+          { \bool_set_false:N \l__chemmacros_State_delta_bool }
+          {
+            \bool_set_true:N \l__chemmacros_State_delta_bool
+            \tl_set:Nn \l__chemmacros_State_delta_tl { #1 }
+          }
+      } ,
+    subscript-left .bool_set:N = \l__chemmacros_State_subscript_left_bool ,
+    subscript-left .default:n  = true ,
+    exponent  .code:n     =
+      {
+        \exp_args:Nf \tl_if_eq:nnTF { #1 } { false }
+          { \bool_set_false:N \l__chemmacros_State_exponent_bool }
+          {
+            \bool_set_true:N \l__chemmacros_State_exponent_bool
+            \tl_set:Nn \l__chemmacros_State_exponent_tl { #1 }
+          }
+      } ,
+    exponent  .default:n  = \standardstate
+  }
+
+% old syntax (v1.1):
+% \State[<exp>,<Delta>,<subscript pos>]{<Symbol>}{<subscript>}
+% old syntax (v2.0):
+% \State[<keyval>]{<Symbol>}{<subscript>}
+% {<subscript>} is an optional argument!
+\cs_new_protected:Npn \chemmacros_state:nnn #1#2#3
+  {
+    \group_begin:
+      \keys_set:nn { chemmacros / state } { #1 }
+      \ensuremath
+       {
+          \bool_if:NT \l__chemmacros_State_delta_bool
+            { \tl_use:N \l__chemmacros_State_delta_tl }
+          \bool_if:NT \l__chemmacros_State_subscript_left_bool
+            { \c_math_subscript_token { \text { #3 } } }
+          #2
+          \bool_if:NF \l__chemmacros_State_subscript_left_bool
+            { \c_math_subscript_token { \text { #3 } } }
+          \bool_if:NT \l__chemmacros_State_exponent_bool
+            { ^ { \tl_use:N \l__chemmacros_State_exponent_tl } }
+        }
+    \group_end:
+  }
+\cs_generate_variant:Nn \chemmacros_state:nnn { xnV }
+
+\NewDocumentCommand \State { s O{} m G{} }
+  {
+    \group_begin:
+      \IfBooleanT { #1 }
+        {
+          \keys_set:nn { chemmacros / state }
+            { subscript-left = false , exponent = }
+        }
+      \chemmacros_state:nnn { #2 } { #3 } { #4 }
+    \group_end:
+  }
+
+% --------------------------------------------------------------------------
+\tl_new:N  \l__chemmacros_thermod_subscript_left_tl
+\tl_new:N  \l__chemmacros_thermod_subscript_left_default_tl
+\tl_new:N  \l__chemmacros_thermod_subscript_tl
+\tl_new:N  \l__chemmacros_thermod_subscript_default_tl
+\tl_new:N  \l__chemmacros_thermod_unit_tl
+\tl_new:N  \l__chemmacros_thermod_exponent_tl
+\tl_new:N  \l__chemmacros_thermod_exponent_default_tl
+\tl_set:Nn \l__chemmacros_thermod_exponent_default_tl { \standardstate }
+\tl_new:N  \l__chemmacros_thermod_delta_tl
+\tl_new:N  \l__chemmacros_thermod_delta_default_tl
+\tl_set:Nn \l__chemmacros_thermod_delta_default_tl { \changestate }
+
+\bool_new:N \l__chemmacros_renewstate_bool
+\bool_new:N \l__chemmacros_state_overwrite_error_bool
+
+\keys_define:nn { chemmacros }
+  {
+    State / subscript         .choice: ,
+    State / subscript / left  .code:n   =
+      { \tl_set:Nn \l__chemmacros_thermod_subscript_left_tl { true } } ,
+    State / subscript / right .code:n   =
+      { \tl_set:Nn \l__chemmacros_thermod_subscript_left_tl { false } } ,
+    State / exponent          .tl_set:N =
+      \l__chemmacros_thermod_exponent_tl ,
+    State / delta             .tl_set:N =
+      \l__chemmacros_thermod_delta_tl ,
+    State / unit              .tl_set:N =
+      \l__chemmacros_thermod_unit_tl ,
+    setnewstate / subscript-left .tl_set:N =
+      \l__chemmacros_thermod_subscript_left_default_tl ,
+    setnewstate / subscript   .tl_set:N =
+      \l__chemmacros_thermod_subscript_default_tl ,
+    setnewstate / exponent    .tl_set:N =
+      \l__chemmacros_thermod_exponent_default_tl ,
+    setnewstate / delta       .tl_set:N =
+      \l__chemmacros_thermod_delta_default_tl
+  }
+
+% \NewChemState{<name>}[<keyval>]{<symbol>}{<unit>}
+\NewDocumentCommand \NewChemState { omO{}mm }
+  {
+    \bool_set_false:N \l__chemmacros_renewstate_bool
+    \bool_set_true:N \l__chemmacros_state_overwrite_error_bool
+    \__chemmacros_setnewstate_reset:
+    \IfNoValueTF { #1 }
+      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
+      {
+        \msg_warning:nn { chemmacros } { state-syntax }
+        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
+      }
+  }
+% \DeclareChemState{<name>}[<keyval>]{<symbol>}{<unit>}
+\NewDocumentCommand \DeclareChemState { omO{}mm }
+  {
+    \bool_set_false:N \l__chemmacros_renewstate_bool
+    \bool_set_false:N \l__chemmacros_state_overwrite_error_bool
+    \__chemmacros_setnewstate_reset:
+    \IfNoValueTF { #1 }
+      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
+      {
+        \msg_warning:nn { chemmacros } { state-syntax }
+        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
+      }
+  }
+% \RenewChemState{<name>}[<keyval>]{<symbol>}{<unit>}
+\NewDocumentCommand \RenewChemState { omO{}mm }
+  {
+    \bool_set_true:N \l__chemmacros_renewstate_bool
+    \bool_set_true:N \l__chemmacros_state_overwrite_error_bool
+    \__chemmacros_setnewstate_reset:
+    \IfNoValueTF { #1 }
+      { \chemmacros_define_state:nnnn { #3 } { #2 } { #4 } { #5 } }
+      {
+        \msg_warning:nn { chemmacros } { state-syntax }
+        \chemmacros_define_state:nnnn { #1#3 } { #2 } { #4 } { #5 }
+      }
+  }
+% TODO
+\cs_set_protected:Npn \setnewstate
+  {
+    \msg_warning:nnnn { chemmacros } { command-deprecated }
+      { \setnewstate } { \NewChemState }
+    \NewChemState
+  }
+\cs_set_protected:Npn \renewstate
+  {
+    \msg_warning:nnnn { chemmacros } { command-deprecated }
+      { \renewstate } { \RenewChemState }
+    \RenewChemState
+  }
+
+\cs_new_protected:Npn \__chemmacros_setnewstate_reset:
+  {
+    \tl_set:Nn  \l__chemmacros_thermod_subscript_left_default_tl { true }
+    \tl_clear:N \l__chemmacros_thermod_subscript_default_tl
+    \tl_set:Nn  \l__chemmacros_thermod_exponent_default_tl { \standardstate }
+    \tl_set:Nn  \l__chemmacros_thermod_delta_default_tl { \changestate }
+  }
+
+\cs_new_protected:Npn \chemmacros_define_state:nnnn #1#2#3#4
+  {
+    \keys_set:nn { chemmacros / setnewstate } { #1 }
+    \chemmacros_if_is_cs:nTF { #2 }
+      { \__chemmacros_set_state:xnn { \cs_to_str:N #2 } { #3 } { #4 } }
+      {
+        \msg_warning:nn { chemmacros } { state-syntax }
+        \__chemmacros_set_state:nnn { #2 } { #3 } { #4 }
+      }
+  }
+
+\cs_new_protected:Npn \__chemmacros_set_state:nnn #1#2#3
+  {
+    \bool_if:NT \l__chemmacros_state_overwrite_error_bool
+      {
+        \bool_if:NTF \l__chemmacros_renewstate_bool
+          {
+            \cs_if_exist:cF { #1 }
+              { \msg_error:nnx { chemmacros } { nenew-state } { #1 } }
+          }
+          {
+            \cs_if_exist:cT { #1 }
+              { \msg_error:nnx { chemmacros } { new-state } { #1 } }
+          }
+      }
+    \cs_undefine:c { chemmacros_ #1 _reset: }
+    \cs_undefine:c { c__chemmacros_ #1 _subscript_tl }
+    \cs_undefine:c { c__chemmacros_ #1 _exponent_tl }
+    \cs_undefine:c { c__chemmacros_ #1 _delta_tl }
+    \cs_undefine:c { c__chemmacros_ #1 _left_tl }
+    \cs_undefine:c { c__chemmacros_ #1 _unit_tl }
+    \cs_undefine:c { #1 }
+    \cs_undefine:c { #1 _aux_i:n }
+    \cs_undefine:c { #1 _aux_ii:n }
+    \cs_undefine:c { #1 _aux_iii:n }
+    \group_begin:
+      \tl_const:cV
+        { c__chemmacros_ #1 _subscript_tl }
+        \l__chemmacros_thermod_subscript_default_tl
+      \tl_const:cV
+        { c__chemmacros_ #1 _exponent_tl }
+        \l__chemmacros_thermod_exponent_default_tl
+      \tl_const:cV
+        { c__chemmacros_ #1 _delta_tl }
+        \l__chemmacros_thermod_delta_default_tl
+      \tl_const:cV
+        { c__chemmacros_ #1 _left_tl }
+        \l__chemmacros_thermod_subscript_left_default_tl
+      \tl_const:cn
+        { c__chemmacros_ #1 _unit_tl }
+        { #3 }
+      \cs_new_protected:cpn {chemmacros_ #1 _reset: }
+        {
+          \tl_set_eq:Nc
+            \l__chemmacros_thermod_subscript_tl
+            { c__chemmacros_ #1 _subscript_tl }
+          \tl_set_eq:Nc
+            \l__chemmacros_thermod_exponent_tl
+            { c__chemmacros_ #1 _exponent_tl }
+          \tl_set_eq:Nc
+            \l__chemmacros_thermod_delta_tl
+            { c__chemmacros_ #1 _delta_tl }
+          \tl_set_eq:Nc
+            \l__chemmacros_thermod_subscript_left_tl
+            { c__chemmacros_ #1 _left_tl }
+          \tl_set_eq:Nc
+            \l__chemmacros_thermod_unit_tl
+            { c__chemmacros_ #1 _unit_tl }
+        }
+      \cs_new_protected:cpn { #1 }
+        {
+          \use:c {chemmacros_ #1 _reset: }
+          \peek_meaning:NTF [
+            { \tl_use:c { #1 _aux_i:n } }
+            {
+              \peek_meaning:NTF (
+                { \tl_use:c { #1 _aux_ii:n } }
+                { \tl_use:c { #1 _aux_iii:n } }
+            }
+        }
+      \cs_new_protected:cpn { #1 _aux_i:n } [##1]
+        {
+          \keys_set:nn { chemmacros / State } { ##1 }
+          \peek_meaning:NTF (
+            { \tl_use:c { #1 _aux_ii:n } }
+            { \tl_use:c { #1 _aux_iii:n } }
+        }
+      \cs_new_protected:cpn { #1 _aux_ii:n } (##1)
+        {
+          \tl_set:Nn \l__chemmacros_thermod_subscript_tl { ##1 }
+          \tl_use:c { #1 _aux_iii:n }
+        }
+      \cs_new_protected:cpn { #1 _aux_iii:n } ##1
+        {
+          \ensuremath
+            {
+              \tl_if_eq:VnTF
+                \l__chemmacros_thermod_subscript_left_tl { true }
+                {
+                  \chemmacros_state:xnV
+                    {
+                      subscript-left = true ,
+                      exponent       =
+                        { \exp_not:V \l__chemmacros_thermod_exponent_tl } ,
+                      delta          =
+                        { \exp_not:V \l__chemmacros_thermod_delta_tl }
+                    }
+                    { #2 }
+                }
+                {
+                  \chemmacros_state:xnV
+                    {
+                      subscript-left = false ,
+                      exponent       =
+                        { \exp_not:V \l__chemmacros_thermod_exponent_tl } ,
+                      delta          =
+                        { \exp_not:V \l__chemmacros_thermod_delta_tl }
+                    }
+                    { #2 }
+                }
+                \l__chemmacros_thermod_subscript_tl
+                =
+                \exp_args:NnV \SI { ##1 } \l__chemmacros_thermod_unit_tl
+            }
+        }
+    \group_end:
+    \ignorespaces
+  }
+\cs_generate_variant:Nn \__chemmacros_set_state:nnn { x }
+
+% predefined:
+\NewChemState \Enthalpy {H} {\kilo\joule\per\mole}
+\NewChemState \Entropy [ delta=false, subscript-left=false ]
+  {S} {\joule\per\kelvin\per\mole}
+\NewChemState \Gibbs {G} {\kilo\joule\per\mole}
+
+% --------------------------------------------------------------------------
+% Newman projections
+\fp_new:N  \l__chemmacros_newman_rel_angle_fp
+\fp_zero:N \l__chemmacros_newman_rel_angle_fp
+\fp_new:N  \l__chemmacros_newman_tmp_angle_fp
+\fp_new:N  \l__chemmacros_newman_abs_angle_fp
+\fp_zero:N \l__chemmacros_newman_abs_angle_fp
+\fp_new:N  \l__chemmacros_newman_scale_fp
+\fp_set:Nn \l__chemmacros_newman_scale_fp { 1 }
+\fp_new:N  \l__chemmacros_newman_x_fp
+\fp_new:N  \l__chemmacros_newman_y_fp
+
+\tl_new:N \l__chemmacros_newman_tikz_ring_tl
+\tl_new:N \l__chemmacros_newman_tikz_front_tl
+\tl_new:N \l__chemmacros_newman_tikz_back_tl
+
+\bool_new:N \l__chemmacros_newman_tikz_back_bool
+
+\keys_define:nn { chemmacros / newman }
+  {
+    ring       .tl_set:N  = \l__chemmacros_newman_tikz_ring_tl ,
+    atoms      .tl_set:N  = \l__chemmacros_newman_tikz_front_tl ,
+    back-atoms .code:n    =
+      {
+        \bool_set_true:N \l__chemmacros_newman_tikz_back_bool
+        \tl_set:Nn \l__chemmacros_newman_tikz_back_tl { #1 }
+      } ,
+    scale       .fp_set:N  = \l__chemmacros_newman_scale_fp ,
+    scale       .default:n = 1 ,
+    angle       .fp_set:N  = \l__chemmacros_newman_abs_angle_fp ,
+    angle       .default:n = 0
+  }
+
+% \newman[<keyval>](<angle>){<1>,<2>,<3>,<4>,<5>,<6>}
+\NewDocumentCommand \newman { o d() > { \SplitArgument { 5 } { , } } m }
+  {
+    \group_begin:
+      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / newman } { #1 } }
+      \IfNoValueTF { #2 }
+        { \chemmacros_newman_atoms:nnnnnnn {    } #3 }
+        { \chemmacros_newman_atoms:nnnnnnn { #2 } #3 }
+    \group_end:
+  }
+
+% place atoms:
+% #1: angle
+% #2 - #7: atoms
+\cs_new_protected:Npn \chemmacros_newman_atoms:nnnnnnn #1#2#3#4#5#6#7
+  {
+    \tl_if_blank:nTF { #1 }
+      {
+        \fp_set_eq:NN
+          \l__chemmacros_newman_rel_angle_fp
+          \l__chemmacros_newman_abs_angle_fp
+      }
+      { \fp_set:Nn \l__chemmacros_newman_rel_angle_fp { #1 } }
+    \chemmacros_tikz_picture:xn
+      {
+        scale = \fp_to_tl:N \l__chemmacros_newman_scale_fp ,
+        chemmacros_newman_atom_front / .style =
+          {
+            inner~sep=0pt,
+            outer~sep=0pt,
+            \tl_use:N \l__chemmacros_newman_tikz_front_tl
+          },
+        chemmacros_newman_atom_back / .style =
+          {
+            inner~sep=0pt,
+            outer~sep=0pt,
+            \bool_if:NTF \l__chemmacros_newman_tikz_back_bool
+              { \tl_use:N \l__chemmacros_newman_tikz_back_tl }
+              { \tl_use:N \l__chemmacros_newman_tikz_front_tl }
+          }
+      }
+      {
+        \chemmacros_tikz_draw:f
+          { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
+          (0pt,0pt) circle (\fp_to_dim:N \l__chemmacros_newman_scale_fp * 15) ;
+        \chemmacros_newman_back_node:nn
+          { 30 }
+          { \IfNoValueF { #6 } { #6 } }
+        \chemmacros_newman_back_node:nf
+          { 150 }
+          { \IfNoValueF { #7 } { #7 } }
+        \chemmacros_newman_back_node:nf
+          { 270 }
+          { \IfNoValueF { #5 } { #5 } }
+        \chemmacros_newman_front_node:nf
+          { 90 }
+          { \IfNoValueF { #2 } { #2 } }
+        \chemmacros_newman_front_node:nf
+          { 210 }
+          { \IfNoValueF { #3 } { #3 } }
+        \chemmacros_newman_front_node:nf
+          { 330 }
+          { \IfNoValueF { #4 } { #4 } }
+    }
+  }
+
+% provide cartesian coordiantes from polar coordinates
+% #1: fp variable for x
+% #2: fp variable for y
+% #3: angle
+% #4: radius
+\cs_new_protected:Npn \chemmacros_polar_to_cartesian:NNnn #1#2#3#4
+  {
+    \fp_set:Nn #1 { #4 * cos( #3 / 180 * pi ) }% x
+    \fp_set:Nn #2 { #4 * sin( #3 / 180 * pi ) }% y
+  }
+
+% place back nodes
+\cs_new_protected:Npn \chemmacros_newman_back_node:nn #1#2
+  {
+    \group_begin:
+      \fp_add:Nn \l__chemmacros_newman_rel_angle_fp { #1 }
+      \chemmacros_polar_to_cartesian:NNnn
+        \l__chemmacros_newman_x_fp
+        \l__chemmacros_newman_y_fp
+        { \l__chemmacros_newman_rel_angle_fp }
+        { \l__chemmacros_newman_scale_fp }
+      \chemmacros_tikz_draw:f
+        { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
+        (
+          15 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          15 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        )
+        --
+        (
+          30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        ) ;
+      \chemmacros_polar_to_cartesian:NNnn
+        \l__chemmacros_newman_x_fp
+        \l__chemmacros_newman_y_fp
+        { \l__chemmacros_newman_rel_angle_fp }
+        { \l__chemmacros_newman_scale_fp }
+      \chemmacros_tikz_node:f
+        {
+          chemmacros_newman_atom_back,
+          anchor = -180 + \fp_to_int:N \l__chemmacros_newman_rel_angle_fp
+        }
+        at
+        (
+          31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+          31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+        )
+        { #2 } ;
+    \group_end:
+  }
+\cs_generate_variant:Nn \chemmacros_newman_back_node:nn { nf }
+
+% place front nodes:
+\cs_new_protected:Npn \chemmacros_newman_front_node:nn #1#2
+  {
+    \chemmacros_polar_to_cartesian:NNnn
+      \l__chemmacros_newman_x_fp
+      \l__chemmacros_newman_y_fp
+      { #1 }
+      { \l__chemmacros_newman_scale_fp }
+    \chemmacros_tikz_draw:f
+      { \tl_use:N \l__chemmacros_newman_tikz_ring_tl }
+      (0pt,0pt) -- ++
+      (
+        30 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+        30 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+      ) ;
+    \chemmacros_polar_to_cartesian:NNnn
+      \l__chemmacros_newman_x_fp
+      \l__chemmacros_newman_y_fp
+      { #1 }
+      { \l__chemmacros_newman_scale_fp }
+    \chemmacros_tikz_node:f
+      { chemmacros_newman_atom_front, anchor = -180 + #1 }
+      at
+      (
+        31 * \fp_to_dim:N \l__chemmacros_newman_x_fp ,
+        31 * \fp_to_dim:N \l__chemmacros_newman_y_fp
+      )
+      { #2 } ;
+  }
+\cs_generate_variant:Nn \chemmacros_newman_front_node:nn { nf }
+
+% --------------------------------------------------------------------------
+% \orbital[<keyval>]{<type>}
+% variables:
+\bool_new:N      \l__chemmacros_orbital_type_s_bool
+\bool_new:N      \l__chemmacros_orbital_type_p_bool
+\bool_new:N      \l__chemmacros_orbital_type_sp_bool
+\bool_new:N      \l__chemmacros_orbital_type_sptwo_bool
+\bool_new:N      \l__chemmacros_orbital_type_spthree_bool
+\bool_new:N      \l__chemmacros_orbital_s_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_s_phase_bool
+\bool_new:N      \l__chemmacros_orbital_p_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_p_phase_bool
+\bool_new:N      \l__chemmacros_orbital_sp_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_sp_phase_bool
+\bool_new:N      \l__chemmacros_orbital_sptwo_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool
+\bool_new:N      \l__chemmacros_orbital_spthree_phase_bool
+\bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool
+\bool_new:N      \l__chemmacros_orbital_p_half_bool
+\bool_new:N      \l__chemmacros_orbital_overlay_bool
+\bool_new:N      \l__chemmacros_orbital_opacity_bool
+
+\tl_new:N  \l__chemmacros_orbital_s_color_tl
+\tl_set:Nn \l__chemmacros_orbital_s_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_s_phase_color_tl
+\tl_new:N  \l__chemmacros_orbital_p_color_tl
+\tl_set:Nn \l__chemmacros_orbital_p_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_p_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_p_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sp_color_tl
+\tl_set:Nn \l__chemmacros_orbital_sp_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_sp_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sp_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sptwo_color_tl
+\tl_set:Nn \l__chemmacros_orbital_sptwo_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_sptwo_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_sptwo_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_spthree_color_tl
+\tl_set:Nn \l__chemmacros_orbital_spthree_color_tl { black }
+\tl_new:N  \l__chemmacros_orbital_spthree_pphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_spthree_mphase_color_tl
+\tl_new:N  \l__chemmacros_orbital_s_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_s_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_p_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_p_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_sp_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_sp_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_sptwo_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_sptwo_scale_tl { 1 }
+\tl_new:N  \l__chemmacros_orbital_spthree_scale_tl
+\tl_set:Nn \l__chemmacros_orbital_spthree_scale_tl { 1 }
+
+\fp_new:N  \l__chemmacros_orbital_angle_fp
+\fp_set:Nn \l__chemmacros_orbital_angle_fp { 90 }
+\fp_new:N  \l__chemmacros_orbital_opacity_fp
+\fp_set:Nn \l__chemmacros_orbital_opacity_fp { 0.5 }
+
+\cs_new:Npn \__chemmacros_orbital_options:
+  {
+    \__chemmacros_orbital_overlay: , \__chemmacros_orbital_opacity: ,
+    inner~sep=0 , outer~sep=0 , line~width=.2pt ,
+    rotate = { \fp_use:N \l__chemmacros_orbital_angle_fp - 90 } ,
+    baseline ,
+    minimum~size = 0
+  }
+
+\cs_new:Npn \__chemmacros_orbital_overlay:
+  { \bool_if:NT \l__chemmacros_orbital_overlay_bool { overlay } }
+
+\cs_new:Npn \__chemmacros_orbital_opacity:
+  {
+    \bool_if:NT \l__chemmacros_orbital_opacity_bool
+      { opacity = { \fp_use:N \l__chemmacros_orbital_opacity_fp } }
+  }
+
+% --------------------------------------------------------------------------
+% s-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_s:
+  {
+    \bool_set_true:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / s }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_s_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_s_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_s_scale_tl ,
+    color .tl_set:N   = \l__chemmacros_orbital_s_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_s_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / s } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_s_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_s_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_s_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_s_color_tl ! 90 }
+          }
+      }
+      {
+        \tl_set:Nn \l__chemmacros_orbital_s_phase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn{ \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shade:f
+          { ball~color = \l__chemmacros_orbital_s_phase_color_tl }
+          (0pt,0pt) circle (\l__chemmacros_orbital_s_scale_tl * .6em) ;
+      }
+  }
+
+% --------------------------------------------------------------------------
+% p-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_p:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / p }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_p_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_p_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_p_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_p_color_tl ,
+    half  .bool_set:N = \l__chemmacros_orbital_p_half_bool ,
+    half  .default:n  = true
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_p_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / p } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_p_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_p_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_p_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_p_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_p_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_p_pphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_p_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_p_scale_tl * 2em ,
+            \l__chemmacros_orbital_p_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_p_scale_tl * 2em ,
+            \l__chemmacros_orbital_p_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \bool_if:NF \l__chemmacros_orbital_p_half_bool
+          {
+            \chemmacros_tikz_shadedraw:f
+              {
+                draw = \l__chemmacros_orbital_p_mphase_color_tl ,
+                ball~color = \l__chemmacros_orbital_p_mphase_color_tl
+              }
+              (0pt,0pt) .. controls ++
+              (
+                - \l__chemmacros_orbital_p_scale_tl * 2em ,
+                - \l__chemmacros_orbital_p_scale_tl * 2em
+              )
+              and ++
+              (
+                \l__chemmacros_orbital_p_scale_tl * 2em ,
+                - \l__chemmacros_orbital_p_scale_tl * 2em
+              )
+              .. (0pt,0pt);
+          }
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_sp:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_sp_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_sp_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_sp_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_sp_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_sp_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_sp_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sp_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sp_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sp_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sp_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_sp_pphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_sp_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sp_scale_tl * 2em ,
+            \l__chemmacros_orbital_sp_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sp_scale_tl * 2em ,
+            \l__chemmacros_orbital_sp_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_sp_mphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_sp_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sp_scale_tl * .6em ,
+            - \l__chemmacros_orbital_sp_scale_tl * .6em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sp_scale_tl * .6em ,
+            - \l__chemmacros_orbital_sp_scale_tl * .6em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp2-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_sptwo:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp2 }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_sptwo_phase_bool } ,
+    phase / - .code:n =
+      { \bool_set_false:N \l__chemmacros_orbital_sptwo_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_sptwo_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_sptwo_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_sptwo_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp2 } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_sptwo_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_sptwo_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_sptwo_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_sptwo_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_sptwo_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_sptwo_pphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_sptwo_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em ,
+            \l__chemmacros_orbital_sptwo_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_sptwo_mphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_sptwo_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_sptwo_scale_tl * .8em ,
+            - \l__chemmacros_orbital_sptwo_scale_tl * .8em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% sp3-orbitals
+\cs_new_protected:Npn \__chemmacros_orbital_type_spthree:
+  {
+    \bool_set_false:N \l__chemmacros_orbital_type_s_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_p_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sp_bool
+    \bool_set_false:N \l__chemmacros_orbital_type_sptwo_bool
+    \bool_set_true:N  \l__chemmacros_orbital_type_spthree_bool
+  }
+
+\keys_define:nn { chemmacros / orbital / sp3 }
+  {
+    phase .choice: ,
+    phase / + .code:n =
+      { \bool_set_true:N \l__chemmacros_orbital_spthree_phase_bool } ,
+    phase / - .code:n =
+     { \bool_set_false:N \l__chemmacros_orbital_spthree_phase_bool } ,
+    scale .tl_set:N   = \l__chemmacros_orbital_spthree_scale_tl ,
+    angle .fp_set:N   = \l__chemmacros_orbital_angle_fp ,
+    color .tl_set:N   = \l__chemmacros_orbital_spthree_color_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_orbital_spthree_draw:n #1
+  {
+    \keys_set:nn { chemmacros / orbital / sp3 } { #1 }
+    \bool_if:NTF \l__chemmacros_orbital_spthree_phase_bool
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+          { black ! 5 }
+        
+      }
+      {
+        \tl_if_in:NnTF \l__chemmacros_orbital_spthree_color_tl { ! }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl }
+          }
+          {
+            \tl_set:Nn \l__chemmacros_orbital_spthree_mphase_color_tl
+              { \tl_use:N \l__chemmacros_orbital_spthree_color_tl ! 90 }
+          }
+        \tl_set:Nn \l__chemmacros_orbital_spthree_pphase_color_tl
+          { black ! 5 }
+      }
+    \chemmacros_tikz_picture:xn { \__chemmacros_orbital_options: }
+      {
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_spthree_pphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_spthree_pphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_spthree_scale_tl * 2em ,
+            \l__chemmacros_orbital_spthree_scale_tl * 2em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_spthree_scale_tl * 2em ,
+            \l__chemmacros_orbital_spthree_scale_tl * 2em
+          )
+          .. (0pt,0pt);
+        \chemmacros_tikz_shadedraw:f
+          {
+            draw = \l__chemmacros_orbital_spthree_mphase_color_tl ,
+            ball~color = \l__chemmacros_orbital_spthree_mphase_color_tl
+          }
+          (0pt,0pt) .. controls ++
+          (
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em ,
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em
+          )
+          and ++
+          (
+            \l__chemmacros_orbital_spthree_scale_tl * 1em ,
+            - \l__chemmacros_orbital_spthree_scale_tl * 1em
+          )
+          .. (0pt,0pt);
+      }
+  }
+
+% --------------------------------------------------------------------------
+% main command
+\keys_define:nn { chemmacros / orbital }
+  {
+    overlay .bool_set:N = \l__chemmacros_orbital_overlay_bool ,
+    overlay .default:n  = true ,
+    opacity .code:n     =
+      {
+        \fp_compare:nTF { #1 = 1 }
+          { \bool_set_false:N \l__chemmacros_orbital_opacity_bool }
+          { \bool_set_true:N \l__chemmacros_orbital_opacity_bool }
+        \fp_set:Nn \l__chemmacros_orbital_opacity_fp { #1 }
+      }
+  }
+
+\keys_define:nn { chemmacros / orbital / type }
+  {
+    s   .code:n = { \__chemmacros_orbital_type_s: } ,
+    p   .code:n = { \__chemmacros_orbital_type_p: } ,
+    sp  .code:n = { \__chemmacros_orbital_type_sp: } ,
+    sp2 .code:n = { \__chemmacros_orbital_type_sptwo: } ,
+    sp3 .code:n = { \__chemmacros_orbital_type_spthree: }
+  }
+
+\cs_new_protected:Npn \chemmacros_orbital:n #1
+  {
+    \bool_if:NT \l__chemmacros_orbital_type_s_bool
+      { \__chemmacros_orbital_s_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_p_bool
+      { \__chemmacros_orbital_p_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_sp_bool
+      { \__chemmacros_orbital_sp_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_sptwo_bool
+      { \__chemmacros_orbital_sptwo_draw:n { #1 } }
+    \bool_if:NT \l__chemmacros_orbital_type_spthree_bool
+      { \__chemmacros_orbital_spthree_draw:n { #1 } }
+  }
+
+\NewDocumentCommand \orbital { o m }
+  {
+    \group_begin:
+      \keys_set:nn { chemmacros / orbital / type } { #2 }
+      \IfNoValueTF { #1 }
+        { \chemmacros_orbital:n {    } }
+        { \chemmacros_orbital:n { #1 } }
+    \group_end:
+  }
+
+% --------------------------------------------------------------------------
+% arrow tips for electron movement
+\dim_new:N \l__chemmacros_el_length_dim
+
+% full tip for pairs
+\pgfarrowsdeclare { el } { el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { .3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto
+      { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { -.3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+
+% half tip on the left
+\pgfarrowsdeclare { left~el } { left~el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { .3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+
+% half tip in the right
+\pgfarrowsdeclare { right~el } { right~el }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfarrowsleftextend { -\l__chemmacros_el_length_dim }
+    \pgfarrowsrightextend { .5\pgflinewidth }
+  }
+  {
+    \dim_set:Nn \l__chemmacros_el_length_dim
+      { 2.5pt + 2.5\pgflinewidth }
+    \pgfsetdash {} { 0pt }
+    \pgfsetroundjoin
+    \pgfsetroundcap
+    \pgfpathmoveto { \pgfpoint { 0pt } { 0pt } }
+    \pgfpathlineto
+      {
+        \pgfpoint
+          { -\l__chemmacros_el_length_dim }
+          { -.3\l__chemmacros_el_length_dim }
+      }
+    \pgfpathlineto { \pgfpoint { -.5\l__chemmacros_el_length_dim } { 0pt } }
+    \pgfpathlineto { \pgfpoint { 0pt } { 0pt } }
+    \pgfusepathqfillstroke
+  }
+
+% --------------------------------------------------------------------------
+% setup
+\NewDocumentCommand \chemsetup { o m }
+  {
+    \IfNoValueTF { #1 }
+      { \keys_set:nn { chemmacros } { #2 } }
+      {
+        \tl_if_eq:nnTF { #1 } { chemformula }
+          { \setchemformula { #2 } }
+          { \keys_set:nn { chemmacros / #1 } { #2 } }
+      }
+    \ignorespaces
+  }
+
+
+% --------------------------------------------------------------------------
+% hyperref support
+% ?? unsure about adding IUPAC commands
+\AfterPackage* { hyperref }
+  {
+    \pdfstringdefDisableCommands
+      {
+        % \cs_set:Npn \- { - } % maybe not a good idea...
+        \cs_set:Npn \| { }
+        \cs_set:Npn \pH { pH }
+        \cs_set:Npn \pOH { pOH }
+        \cs_set:Npn \iupac #1 { #1 }
+        \cs_set:Npn \cip #1 { (#1) }
+        \cs_set:Npn \cis { cis }
+        \cs_set:Npn \trans { trans }
+        \cs_set:Npn \tert { tert }
+        \cs_set:Npn \ortho { o }
+        \cs_set:Npn \meta { m }
+        \cs_set:Npn \para { p }
+        \cs_set:Npn \syn { syn }
+        \cs_set:Npn \anti { anti }
+      }
+  }
+
+% --------------------------------------------------------------------------
+% language support -- provided through `translations'
+% equilibrium constants:
+\DeclareTranslationFallback {K-acid}  {\mathrm{a}}
+\DeclareTranslation{German} {K-acid}  {\mathrm{s}}
+\DeclareTranslation{Dutch}  {K-acid}  {\mathrm{z}}
+
+\DeclareTranslationFallback {K-base}  {\mathrm{b}}
+
+\DeclareTranslationFallback {K-water} {\mathrm{w}}
+
+% phases:
+\DeclareTranslation{German}{phase-sld}{ f }
+\DeclareTranslation{German}{phase-lqd}{ f{}l }
+% list of reactions:
+\DeclareTranslationFallback  {list-of-reactions} { List~ of~ reactions }
+\DeclareTranslation{English} {list-of-reactions} { List~ of~ reactions }
+\DeclareTranslation{German}  {list-of-reactions} { Reaktionsverzeichnis }
+\DeclareTranslation{Italian} {list-of-reactions} { Elenco~ delle~ reazioni }
+\DeclareTranslation{French}  {list-of-reactions} { Table~ des~ r\'eactions }
+\DeclareTranslation{Dutch}   {list-of-reactions} { Lijst~ van~ reacties }
+%
+\DeclareTranslationFallback  {reaction} { Reaction }
+\DeclareTranslation{English} {reaction} { Reaction }
+\DeclareTranslation{German}  {reaction} { Reaktion }
+\DeclareTranslation{Italian} {reaction} { Reazione }
+\DeclareTranslation{French}  {reaction} { R\'eaction }
+\DeclareTranslation{Dutch}   {reaction} { Reactie }
+
+\tl_set:Nn \l__chemmacros_reaction_lorname_tl
+  { \chemmacros_translate:n {reaction} }
+\tl_set:Nn \reactionlistname
+  { \chemmacros_translate:n {list-of-reactions} }
+
+\tex_endinput:D
+
+% --------------------------------------------------------------------------
+Version history
+2015/08/29 - version 5.0  - integration as v4.7 into v5.0 of chemmacros for
+                            backwards compatibility
+                          - fix typo in \l_chemformula_formal_charges_bool
+                          - remove \tl_to_lowercase:n
+
+% --------------------------------------------------------------------------- %
+% TODO:
+- add d-orbitals
+- make electron movement arrow tips (`el', `left el' and `right el') public
+- phase commands with arguments (see http://texwelt.de/wissen/fragen/9264)
+
diff --git a/Master/texmf-dist/tex/latex/chemmacros/chemmacros5.sty b/Master/texmf-dist/tex/latex/chemmacros/chemmacros5.sty
new file mode 100644
index 00000000000..7b191bf4948
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/chemmacros/chemmacros5.sty
@@ -0,0 +1,243 @@
+% --------------------------------------------------------------------------
+% the CHEMMACROS package
+%
+%   comprehensive support for typesetting chemistry documents
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% --------------------------------------------------------------------------
+% https://github.org/cgnieder/chemmacros/
+% contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011-2015 Clemens Niederberger
+%
+% This work may be distributed and/or modified under the
+% conditions of the LaTeX Project Public License, either version 1.3
+% of this license or (at your option) any later version.
+% The latest version of this license is in
+%   http://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX
+% version 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+%
+% The Current Maintainer of this work is Clemens Niederberger.
+% --------------------------------------------------------------------------
+% The chemmacros package consists of the following files
+%  - chemmacros.sty, chemmacros4.sty, chemmacros5.sty,
+%  - chemmacros_en.tex, chemmacros_en.pdf,
+%  - quite a number of module files following the naming scheme
+%    chemmacros.module.*.code.tex
+%  - README
+ % --------------------------------------------------------------------------
+\RequirePackage{expl3,xparse,l3keys2e}
+\ExplSyntaxOn
+
+% --------------------------------------------------------------------------
+% package information:
+\ProvidesExplPackage
+  {chemmacros5}
+  {\c_chemmacros_date_tl}
+  {\c_chemmacros_version_tl}
+  {\c_chemmacros_info_tl \c_space_tl (CN)}
+
+% --------------------------------------------------------------------------
+\msg_new:nnn {chemmacros} {package-option}
+  {
+    Unknown~ option~ `#1'!~ Since~ v5.0~ chemmacros~ has~ no~ package~
+    options~ any~ more!
+  }
+\cs_generate_variant:Nn \msg_warning:nnn { nnV }
+
+\keys_define:nn {chemmacros/package-options}
+  {
+    compatibility .code:n = ,
+    unknown       .code:n =
+      \msg_warning:nnV {chemmacros} {package-option} \CurrentOption
+  }
+
+\ProcessKeysPackageOptions {chemmacros/package-options}
+
+% --------------------------------------------------------------------------
+% messages:
+\msg_new:nnn {chemmacros} {module-missing}
+  {
+    You've~ requested~ the~ chemmacros~ module~ `#1'~ but~ it~ appears~ to~
+    be~ missing~ on~ your~ system.~ Maybe~ you've~ misspelled~ the~ name?~
+    Loading~ the~ module~ will~ abort~ \msg_line_context:
+  }
+
+\msg_new:nnn {chemmacros} {loading-module}
+  {
+    (chemmacros) \c_space_tl \c_space_tl \c_space_tl \c_space_tl
+    Loading~ module~ `#1'...
+  }
+
+% --------------------------------------------------------------------------
+% variants of kernel functions:
+\cs_generate_variant:Nn \tl_if_eq:nnTF       { xx , V }
+\cs_generate_variant:Nn \seq_set_split:Nnn   { Nnx }
+\cs_generate_variant:Nn \prop_item:Nn        { NV }
+\cs_generate_variant:Nn \seq_item:Nn         { cV }
+\cs_generate_variant:Nn \int_to_arabic:n     { V }
+\cs_generate_variant:Nn \tl_replace_once:Nnn { NnV }
+\cs_generate_variant:Nn \prop_gput:Nnn       { cxx , NVf }
+\cs_generate_variant:Nn \msg_error:nnn       { nnV }
+\cs_generate_variant:Nn \msg_warning:nnn     { nnV }
+\cs_generate_variant:Nn \msg_warning:nnnn    { nnV }
+\cs_generate_variant:Nn \vbox_set:Nn         { NV }
+\cs_generate_variant:Nn \keys_define:nn      { x } 
+\cs_generate_variant:Nn \keys_set:nn         { x , nx }
+
+% --------------------------------------------------------------------------
+% temporary variables:
+\tl_new:N    \l__chemmacros_tmpa_tl
+\tl_new:N    \l__chemmacros_tmpb_tl
+\tl_new:N    \l__chemmacros_tmpc_tl
+\tl_new:N    \l__chemmacros_tmpd_tl
+
+\bool_new:N  \l__chemmacros_tmpa_bool
+\bool_new:N  \l__chemmacros_tmpb_bool
+\bool_new:N  \l__chemmacros_tmpc_bool
+
+\dim_new:N   \l__chemmacros_tmpa_dim
+\dim_new:N   \l__chemmacros_tmpb_dim
+\dim_new:N   \l__chemmacros_tmpc_dim
+
+\seq_new:N   \l__chemmacros_tmpa_seq
+\seq_new:N   \l__chemmacros_tmpb_seq
+\seq_new:N   \l__chemmacros_tmpc_seq
+
+\int_new:N   \l__chemmacros_tmpa_int
+\int_new:N   \l__chemmacros_tmpb_int
+\int_new:N   \l__chemmacros_tmpc_int
+
+\box_new:N   \l__chemmacros_tmpa_box
+\box_new:N   \l__chemmacros_tmpb_box
+\box_new:N   \l__chemmacros_tmpc_box
+
+\clist_new:N \l__chemmacros_tmpa_clist
+\clist_new:N \l__chemmacros_tmpb_clist
+\clist_new:N \l__chemmacros_tmpc_clist
+
+% --------------------------------------------------------------------------
+% module mechanism:
+\tl_const:Nn \c__chemmacros_module_extension_tl {code.tex}
+\tl_const:Nn \c__chemmacros_module_prefix_tl    {chemmacros.module}
+
+\cs_new_protected:Npn \chemmacros_load_modules:n #1
+  { \clist_map_inline:nn {#1} { \chemmacros_load_module:n {##1} } }
+
+\cs_new_protected:Npn \chemmacros_load_module:n #1
+  {
+    \tl_set:Nx \l__chemmacros_tmpa_tl { \tl_trim_spaces:n {#1} }
+    \__chemmacros_load_module:V \l__chemmacros_tmpa_tl
+  }
+
+\cs_new_protected:Npn \__chemmacros_load_module:n #1
+  {
+    \chemmacros_if_module_loaded:nF {#1}
+      {
+        \chemmacros_if_module_exist:nTF {#1}
+          {
+            \msg_log:nnn {chemmacros} {loading-module} {#1}
+            \@onefilewithoptions
+              {\c__chemmacros_module_prefix_tl.#1}[][]
+              \c__chemmacros_module_extension_tl
+          }
+          { \msg_error:nnn {chemmacros} {module-missing} {#1} }
+      }
+  }
+\cs_generate_variant:Nn \__chemmacros_load_module:n { V }
+
+\prg_new_conditional:Npnn \chemmacros_if_module_loaded:n #1 {T,F,TF}
+  {
+    \cs_if_exist:cTF  {chemmacros-module-#1-loaded}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\prg_new_conditional:Npnn \chemmacros_if_module_exist:n #1 {T,F,TF}
+  {
+    \file_if_exist:nTF
+      {\c__chemmacros_module_prefix_tl.#1.\c__chemmacros_module_extension_tl}
+      { \prg_return_true: }
+      { \prg_return_false: }
+  }
+
+\cs_new_protected:Npn \chemmacros_module:nnn #1#2#3
+  {
+    \cs_new:cpn {chemmacros-module-#2-loaded} {chemmacros:~module~`#2'}
+    \ProvidesFile
+      {\c__chemmacros_module_prefix_tl.#2.\c__chemmacros_module_extension_tl}
+      [
+        \c_chemmacros_date_tl
+        \c_space_tl
+        v \c_chemmacros_version_tl
+        \c_space_tl
+        chemmacros~ module~ `#2'~ #3
+      ]
+    \bool_if:nF {#1} { \ExplSyntaxOn }
+  }
+
+% --------------------------------------------------------------------------
+% define a chemmacros module:
+% standard modules are written in the expl3 programming environment, the
+% starred version only uses a 2e programming environment, i.e., with @ as a
+% letter
+% #1: boolean
+% #2: name
+% #3: description
+\NewDocumentCommand \ChemModule {smm}
+  { \chemmacros_module:nnn {#1} {#2} {#3} }
+
+% --------------------------------------------------------------------------
+% command for loading modules:
+\NewDocumentCommand \usechemmodule {m} { \chemmacros_load_modules:n {#1} }
+
+% --------------------------------------------------------------------------
+% load default modules:
+\chemmacros_load_modules:n
+  {
+    base, lang, greek, chemformula, % <= those need to be present for all modules
+    acid-base, symbols, charges, particles, phases , nomenclature
+  }
+
+% --------------------------------------------------------------------------
+\tex_endinput:D
+
+% --------------------------------------------------------------------------
+Modules: (* = preloaded)
+ - internal modules:
+   - base *
+   - lang *
+   - greek *
+   - chemformula *
+   - tikz
+ - user modules:
+   - acid-base *
+   - all
+   - charges *
+   - isotopes
+   - mechanisms
+   - newman
+   - nomenclature *
+   - orbital
+   - particles *
+   - phases *
+   - reactions
+   - redox
+   - scheme
+   - spectroscopy
+   - symbols *
+   - thermodynamics
+   - units
+   - xfrac
+
+% --------------------------------------------------------------------------
+Version history
+2015/08/29 v5.0  - major update of chemmacros; please refer to the end of file
+                   chemmacros4.sty for the earlier history