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diff --git a/obsolete/macros/latex/contrib/mychemistry/README b/obsolete/macros/latex/contrib/mychemistry/README
new file mode 100644
index 0000000000..2fe11d7b08
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/README
@@ -0,0 +1,30 @@
+--------------------------------------------------------------------------
+the MYCHEMISTRY package v1.99b 2012/12/19
+
+  create reaction schemes with LaTeX and chemfig
+
+--------------------------------------------------------------------------
+Clemens Niederberger
+Web:    https://www.bitbucket.org/cgnieder/mychemistry
+E-Mail: contact@mychemistry.eu
+--------------------------------------------------------------------------
+If you have any ideas, questions, suggestions or bugs to report, please
+feel free to contact me.
+--------------------------------------------------------------------------
+Copyright 2011--2012 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.
+
+This work consists of the files mychemistrysty, mychemistry_en.tex,
+README and the derived file mychemistry_en.pdf.
+--------------------------------------------------------------------------
\ No newline at end of file
diff --git a/obsolete/macros/latex/contrib/mychemistry/examples.pdf b/obsolete/macros/latex/contrib/mychemistry/examples.pdf
new file mode 100644
index 0000000000..88eda6001e
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/examples.pdf
diff --git a/obsolete/macros/latex/contrib/mychemistry/examples.tex b/obsolete/macros/latex/contrib/mychemistry/examples.tex
new file mode 100644
index 0000000000..46dbc96466
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/examples.tex
@@ -0,0 +1,864 @@
+\documentclass[DIV10]{cnpkgdoc}
+\docsetup{
+  pkg = mychemistry,
+  title = mychemistry -- examples,
+  subtitle = Create Reaction Schemes with \LaTeXe\ and Chemfig ,
+  code-box     = {
+    skipbelow        = .5\baselineskip plus .5ex minus .5ex ,
+    skipabove        = .5\baselineskip plus .5ex minus .5ex ,
+    roundcorner      = 3pt ,
+    innerleftmargin  = 1.5em ,
+    innerrightmargin = 1.5em
+  }
+}
+
+\addcmds{
+  @addtoreset,
+  anywhere,
+  arrow,
+  branch,
+  celsius,
+  ch,
+  chemabove,
+  chemand,
+  chembelow,
+  chemfig,
+  chemname,
+  cmpd,
+  colorlet,
+  command,
+  draw,
+  elmove,
+  floatstyle,
+  fpch,
+  fplus,
+  fscrm,
+  fscrp,
+  Hpl,
+  iupac,
+  lewis,
+  Lewis,
+  listof,
+  makeinvisible,
+  makevisible,
+  marrow,
+  mch,
+  mCsetup,
+  mech,
+  mesomeric,
+  N,
+  node,
+  para,
+  pch,
+  phantom,
+  reactant,
+  restylefloat,
+  setarrowlabel,
+  setarrowlength,
+  setarrowline,
+  setatomsep,
+  setatomsize,
+  setbondlength,
+  setbondshape,
+  setcrambond,
+  setmergelength,
+  setrcndist,
+  setrxnalign,
+  setschemealign,
+  setschemename,
+  SI,
+  text,
+  therxnscheme,
+  tikzset,
+  trans,
+  transition
+}
+
+\chemsetup[option]{circled=all}
+
+\usepackage{chemnum}
+\usepackage{fnpct}
+\usepackage{booktabs}
+\usepackage{siunitx}
+\usepackage{scrhack}
+
+\TitlePicture{%
+  \parbox{.7\linewidth}{%
+     Since the documentation is already long enough I decided to provide an
+     extra file containing only examples and a few words where to find possibly
+     interesting code.\par
+     For all the undocumented little macros like \cmd{fscrp} or \cmd{delm} have
+     a look in the \paket*{chemmacros} documentation.
+  }
+}
+
+\begin{document}
+
+\section{Addition Reaction}\label{sec:addition}
+A simple reaction scheme with two different products.
+
+\begin{rxnscheme}{Addition Reaction}
+ \reactant{ \chemfig{=_[::-30]-[::60](=[::60]O)-[::-60]} }
+ \arrow{ $+ \Hpl$ }{}
+ \mesomeric[,rf]{
+   \reactant{ \chemfig{=_[:-30]-[::60](-[::60]OH)(-[::-120,.3,,,white]\fplus)-[::-60]} }
+   \marrow[below]
+   \reactant[below]{ \chemfig{\fplus-[6,.3,,,white]-[:-30]=_[::60](-[::60]OH)-[::-60]} }
+ }
+ \branch[right=of rf,,yshift=3em]{
+   \arrow{}{}
+   \reactant{ \chemname{\chemfig{=_[:-30]-[::60](-[::60]OH)(-[::-120]R)-[::-60]}}{1,2-adduct} }
+ }
+ \branch[right=of rf,,yshift=-5em]{
+   \arrow{}{}
+   \reactant{ \chemname{\chemfig{R-[6]-[:-30]=_[::60](-[::60]OH)-[::-60]}}{1,4-adduct} }
+ }
+\end{rxnscheme}
+
+
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[,]{Addition Reaction}
+  \reactant{ \chemfig{=_[::-30]-[::60](=[::60]O)-[::-60]} }
+  \arrow{ $+ \Hpl$ }{}
+  \mesomeric[,rf]{
+    \reactant{ \chemfig{=_[:-30]-[::60](-[::60]OH)(-[::-120,.3,,,white]\fplus)-[::-60]} }
+    \marrow[below]
+    \reactant[below]{ \chemfig{\fplus-[6,.3,,,white]-[:-30]=_[::60](-[::60]OH)-[::-60]} }
+  }
+  \branch[right=of rf,,yshift=3em]{
+    \arrow{}{}
+    \reactant{ \chemname{\chemfig{=_[:-30]-[::60](-[::60]OH)(-[::-120]R)-[::-60]}}{1,2-adduct} }
+  }
+  \branch[right=of rf,,yshift=-5em]{
+    \arrow{}{}
+    \reactant{ \chemname{\chemfig{R-[6]-[:-30]=_[::60](-[::60]OH)-[::-60]}}{1,4-adduct} }
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Mesomerism}
+\begin{rxnscheme}[,,,.8]{Mesomerism}
+ \setatomsep{1.6em}
+ \reactant[,start]{ \chemname{\chemfig{*6(-=-=(-[,,,,white]\phantom{Br})-=)}}{benzene \cmpd{benzene}} }
+ \arrow[,,2.8]{}{}
+ \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+ \arrow[start.below,,,pfeil_a]{\ch{Br2} / \ch{AlBr3}}{$-\ch{AlBr4-}$}
+ \mesomeric[pfeil_a.below,mesomerism,xshift=8.5em,yshift=-2.5em]{
+   \reactant{
+     \chemfig{*6(=[@{e1}]-=-(-[:120]Br)(-[:60]H)-(-[:-30,.4,,,white]\fplus)-[@{e2}])}
+     \elmove{e1}{60:4mm}{e2}{0:4mm}
+   }
+   \marrow
+   \reactant{
+     \chemfig{*6(-(-[:90,.4,,,white]\fplus)-[@{e4}]=[@{e3}]-(-[:120]Br)(-[:60]H)-=)}
+     \elmove{e3}{180:4mm}{e4}{150:4mm}
+   }
+   \marrow
+   \reactant{
+     \chemfig{*6(-=-(-[:-150,.4,,,white]\fplus)-(-[:120]Br)(-[:60]H)-=)}
+   }
+ }
+ \branch[above=of mesomerism,,xshift=7.5em]{
+   \arrow[above]{$-\Hpl$}{}
+ }
+\end{rxnscheme}
+
+If you put something relative to an arrow you might have to consider that the
+arrow's anchor point is in the middle of the arrow. That's why \cmd{mesomeric}
+is shifted with \code{yshift=-2.5em} in line 9.
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[,,,.8]{Mesomerism}
+  \setatomsep{1.6em}
+  % main reaction:
+  \reactant[,start]{ \chemname{\chemfig{*6(-=-=(-[,,,,white]\phantom{Br})-=)}}{benzene \cmpd{benzene}} }
+  \arrow[,,2.8]{}{}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+  % branch:
+  \arrow[start.below,,,pfeil_a]{\ch{Br2} / \ch{AlBr3}}{$-\ch{AlBr4-}$}
+  \mesomeric[!!pfeil_a.below!!,mesomerism,xshift=8.5em,!!yshift=-2.5em!!]{
+    \reactant{
+      \chemfig{*6(=[@{e1}]-=-(-[:120]Br)(-[:60]H)-(-[:-30,.4,,,white]\fplus)-[@{e2}])}
+      \elmove{e1}{60:4mm}{e2}{0:4mm}
+    }
+    \marrow
+    \reactant{
+      \chemfig{*6(-(-[:90,.4,,,white]\fplus)-[@{e4}]=[@{e3}]-(-[:120]Br)(-[:60]H)-=)}
+      \elmove{e3}{180:4mm}{e4}{150:4mm}
+    }
+    \marrow
+    \reactant{
+      \chemfig{*6(-=-(-[:-150,.4,,,white]\fplus)-(-[:120]Br)(-[:60]H)-=)}
+    }
+  }
+  % last arrow inside a branch, since it cannot be shifted by itself:
+  \branch[above=of mesomerism,,xshift=7.5em]{
+    \arrow[above]{$-\Hpl$}{}
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{The Former Titlepage}
+This scheme used to be on the title page of the examples file. It isn't any more
+but here's the scheme, anyway.
+\begin{rxnscheme}[,,,.7]{The Titlepage}
+  \setatomsep{1.5em}\footnotesize
+  \reactant[,a]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-C(-[2]CH_3)(-[6]OH)-CH_3} }
+    \arrow[a.20]{}{}
+    \reactant[20]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[@{e1}6,,,2]H_2@{e2}\chembelow{O}{\fplus})-C(-[2]CH_3)(-[6]OH)-CH_3}\elmove{e1}{10:4mm}{e2}{-10:4mm} }
+    \arrow[,,1.42]{$-\ch{H2O}$}{}
+    \reactant{ \chemfig{\chembelow{C}{\fplus}(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))-C(-[2]CH_3)(-[6]OH)-CH_3} }{}
+    \arrow[a.-20,-|>]{}{}
+    \reactant[-20]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-C(-[2]CH_3)(-[@{e3}6]@{e4}\chembelow{O}{\fplus}H_2)-CH_3}\elmove{e3}{170:4mm}{e4}{-170:4mm} }
+    \arrow[,,1.42]{$-\ch{H2O}$}{}
+    \reactant[,end]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-\chembelow{C}{\fplus}(-[2]CH_3)-CH_3} }
+    \anywhere{below=of end}{}
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxn}[,.7]
+  \setatomsep{1.5em}\footnotesize
+  % reaction above:
+  \reactant[,a]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-C(-[2]CH_3)(-[6]OH)-CH_3} }
+  \arrow[a.45]{}{}
+  \reactant[45]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[@{e1}6,,,2]H_2@{e2}\chembelow{O}{\fplus})-C(-[2]CH_3)(-[6]OH)-CH_3}\elmove{e1}{10:4mm}{e2}{-10:4mm} }
+  \arrow[,,1.42]{$-\ch{H2O}$}{}
+  \reactant{ \chemfig{\chembelow{C}{\fplus}(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))-C(-[2]CH_3)(-[6]OH)-CH_3} }{}
+  % going down:
+  \arrow[a.-45,-|>]{}{}
+  \reactant[-45]{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-C(-[2]CH_3)(-[@{e3}6]@{e4}\chembelow{O}{\fplus}H_2)-CH_3}\elmove{e3}{170:4mm}{e4}{-170:4mm} }
+  \arrow[,,1.42]{$-\ch{H2O}$}{}
+  \reactant{ \chemfig{C(-[4]*6(=-=-=-))(-[2]*6(=-=-=-))(-[6,,,2]HO)-\chembelow{C}{\fplus}(-[2]CH_3)-CH_3} }
+ \end{rxn}
+\end{beispiel}
+
+\section{Condensation Reaction}
+\begin{rxnscheme}{Condensation Reaction}
+ \reactant{\chemfig{**6(---(-CH_2OH)-(-OH)--)}}
+ \chemand
+ \reactant{\chemfig{**6(----(-OH)-(-HOCH_2)-)}}
+ \arrow[,-+>]{}{\ch{H2O}}
+ \reactant{\chemfig{**6(---(-CH_2-[:-30]O-[:30]CH_2-[:-30]**6(-----(-OH)-))-(-OH)--)}}
+ \arrow[-90,-+>,,dec]{}{\ch{CH2O}}
+ \anywhere{dec.180,,xshift=-.2em}{\SI{200}{\celsius}}
+ \reactant[-90,target]{\chemfig{**6(---(-CH_2-[:-30]**6(-----(-OH)-))-(-OH)--)}}
+ \branch[left=of target]{
+   \reactant{\chemfig{**6(---(-CH_2OH)-(-OH)--)}}
+   \chemand
+   \reactant{\chemfig{**6(----(-OH)-(-H)-)}}
+   \arrow[,-+>]{}{\ch{H2O}}
+ }
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Condensation Reaction}
+  \reactant{\chemfig{**6(---(-CH_2OH)-(-OH)--)}}
+  \chemand
+  \reactant{\chemfig{**6(----(-OH)-(-HOCH_2)-)}}
+  \arrow[,-+>]{}{\ch{H2O}}
+  \reactant{\chemfig{**6(---(-CH_2-[:-30]O-[:30]CH_2-[:-30]**6(-----(-OH)-))-(-OH)--)}}
+  \arrow[-90,-+>,,dec]{}{\ch{CH2O}}
+  \anywhere{dec.180,,xshift=-.2em}{\SI{200}{\celsius}}
+  \reactant[-90,target]{\chemfig{**6(---(-CH_2-[:-30]**6(-----(-OH)-))-(-OH)--)}}
+  \branch[left=of target]{
+    \reactant{\chemfig{**6(---(-CH_2OH)-(-OH)--)}}
+    \chemand
+    \reactant{\chemfig{**6(----(-OH)-(-H)-)}}
+    \arrow[,-+>]{}{\ch{H2O}}
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Substitution vs. Elimination}
+\begin{rxnscheme}{Substitution vs. Elimination}
+ % first reaction:
+ \reactant[,start_a]{\chemfig{@{H}H-[@{b1}:-60]\chemabove{C}{\scriptstyle\beta}(<[:-100]H)(<:[:-150]H)-[@{b2}]\chemabove{C}{\scriptstyle\alpha}(<[:20]H)(<:[:60]H)-[@{b3}:-60]@{X1}X}}
+ \arrow{E2}{}
+ \reactant{\chemfig{H-[:60]C(-[:120]H)=C(-[:60]H)-[:-60]H}}
+ \chemand
+ \reactant{\ch{X-}}
+ \chemand
+ \reactant{\chemfig{O(-[:60]H)-[:-60]H}}
+ % second reaction:
+ \reactant[start_a.-90,start_b,yshift=-4em]{\chemfig{H-[:-60]C(<[:-100]H)(<:[:-150]H)-@{C}C(<[:20]H)(<:[:60]H)-[@{b4}:-60]@{X2}X}}
+ \arrow{S$_\text{N}$2}{}
+ \reactant{\chemfig{H-[:-60]C(<[:-100]H)(<:[:-150]H)-C(<[:-80]H)(<:[:-30]H)-[:60]OH}}
+ \chemand
+ \reactant{\ch{X-}}
+ % nucleophile/base:
+ \anywhere{start_b.135,nuc,xshift=-3em,yshift=2em}{\chemfig{H-@{O}\chemabove{\lewis{026,O}}{\hspace{5mm}\fscrm}}}
+ % electron movements:
+ \anywhere{nuc.0}{
+   \elmove{O}{90:1.5cm}{H}{180:1cm}
+   \elmove{b1}{60:1cm}{b2}{90:5mm}
+   \elmove{b3}{-170:5mm}{X1}{180:5mm}
+   \elmove{O}{-90:1cm}{C}{100:1.5cm}
+   \elmove{b4}{-170:5mm}{X2}{180:5mm}
+ }
+\end{rxnscheme}
+
+You may see in line 20 that the \cmd{elmove} commands are put inside of
+\cmd{anywhere}. This is necessary in order to produce the right scheme. But this
+time you can position \cmd{anywhere} literally anywhere.
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Substitution vs. Elimination}
+  % first reaction:
+  \reactant[,start_a]{\chemfig{@{H}H-[@{b1}:-60]\chemabove{C}{\scriptstyle\beta}(<[:-100]H)(<:[:-150]H)-[@{b2}]\chemabove{C}{\scriptstyle\alpha}(<[:20]H)(<:[:60]H)-[@{b3}:-60]@{X1}X}}
+  \arrow{\mech[e2}{}
+  \reactant{\chemfig{H-[:60]C(-[:120]H)=C(-[:60]H)-[:-60]H}}
+  \chemand
+  \reactant{\ch{X-}}
+  \chemand
+  \reactant{\chemfig{O(-[:60]H)-[:-60]H}}
+  % second reaction:
+  \reactant[start_a.-90,start_b,yshift=-4em]{\chemfig{H-[:-60]C(<[:-100]H)(<:[:-150]H)-@{C}C(<[:20]H)(<:[:60]H)-[@{b4}:-60]@{X2}X}}
+  \arrow{\mech[2]}{}
+  \reactant{\chemfig{H-[:-60]C(<[:-100]H)(<:[:-150]H)-C(<[:-80]H)(<:[:-30]H)-[:60]OH}}
+  \chemand
+  \reactant{\ch{X-}}
+  % nucleophile/base:
+  \anywhere{start_b.135,nuc,xshift=-3em,yshift=2em}{\chemfig{H-@{O}\chemabove{\lewis{026,O}}{\hspace{5mm}\fscrm}}}
+  % electron movements:
+  \anywhere{nuc.0}{
+    \elmove{O}{90:1.5cm}{H}{180:1cm}
+    \elmove{b1}{60:1cm}{b2}{90:5mm}
+    \elmove{b3}{-170:5mm}{X1}{180:5mm}
+    \elmove{O}{-90:1cm}{C}{100:1.5cm}
+    \elmove{b4}{-170:5mm}{X2}{180:5mm}
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Scheme with three Lines}\label{sec:three_lines}
+\begin{rxnscheme}{Scheme with three Lines}
+ \setatomsep{1.5em}
+ \footnotesize
+ \reactant[,start]{\chemfig{EtO-(=[2]O)-[:-60](-Br)-[:-120](=[6]O)-[4]EtO}}
+ \chemand
+ \reactant{\chemfig{*6(-=-=-*5(-(=O)-\chemabove{\lewis{4:,N}}{\fscrm}(-[4,.7,,,draw=none]\chemabove{K}{\fscrp})-(=O)--)=)}}
+ \arrow{}{}
+ \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[::-60](=[::-60]O)-[::60]EtO)-[::60](=[::60]O)-[::-60]EtO)-(=O)--)=)}}
+ % newline, started with \anywhere:
+ \anywhere{start.-90,a,xshift=-4em,yshift=-5em}{}
+ \arrow[a.0,,.6]{\chemabove{\lewis{0:,B}}{\fscrm}}{}
+ \arrow{\ch{R-X}}{}
+ \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[4]R)(-[::-60](=[::-60]O)-[::60]EtO)-[::60](=[::60]O)-[::-60]EtO)-(=O)--)=)}}
+ \arrow[,,1.25]{\Hpl/\ch{H2O}}{}
+ \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[4]R)(-[::-60](=[::-60]O)-[::60]HO_2C)-[::60](=[::60]O)-[::-60]HO_2C)-(=O)--)=)}}
+ % newline, started with \anywhere:
+ \anywhere{a.-90,b,yshift=-7em}{}
+ \arrow[b.0]{$- {\ch{CO2}}$}{}
+ \arrow{\Hpl}{\ch{H2O}}
+ \reactant{\chemfig{R-(-[6]H)(-[2]C|O_2\mch)-NH_3\pch}}
+\end{rxnscheme}
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Scheme with three Lines}
+  \setatomsep{1.5em}
+  \footnotesize
+  \reactant[,start]{\chemfig{EtO-(=[2]O)-[:-60](-Br)-[:-120](=[6]O)-[4]EtO}}
+  \chemand
+  \reactant{\chemfig{*6(-=-=-*5(-(=O)-\chemabove{\lewis{4:,N}}{\fscrm}(-[4,.7,,,draw=none]\chemabove{K}{\fscrp})-(=O)--)=)}}
+  \arrow{}{}
+  \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[::-60](=[::-60]O)-[::60]EtO)-[::60](=[::60]O)-[::-60]EtO)-(=O)--)=)}}
+  % newline, started with \anywhere:
+  \anywhere{start.-90,a,xshift=-4em,yshift=-5em}{}
+  \arrow[a.0,,.6]{\chemabove{\lewis{0:,B}}{\fscrm}}{}
+  \arrow{\ch{R-X}}{}
+  \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[4]R)(-[::-60](=[::-60]O)-[::60]EtO)-[::60](=[::60]O)-[::-60]EtO)-(=O)--)=)}}
+  \arrow[,,1.25]{\Hpl/\ch{H2O}}{}
+  \reactant{\chemfig{*6(-=-=-*5(-(=O)-N(-(-[4]R)(-[::-60](=[::-60]O)-[::60]HO_2C)-[::60](=[::60]O)-[::-60]HO_2C)-(=O)--)=)}}
+  % newline, started with \anywhere:
+  \anywhere{a.-90,b,yshift=-7em}{}
+  \arrow[b.0]{$- {\ch{CO2}}$}{}
+  \arrow{\Hpl}{\ch{H2O}}
+  \reactant{\chemfig{R-(-[6]H)(-[2]C|O_2\mch)-NH_3\pch}}
+ \end{rxnscheme}
+\end{beispiel}
+
+
+\section{Hydratisation}\label{sec:hydratisation}
+\pgfdeclaredecoration{ddbond}{initial}{%
+  \state{initial}[width=2pt]{%
+    \pgfpathlineto{\pgfpoint{2pt}{0pt}}%
+    \pgfpathmoveto{\pgfpoint{1.5pt}{2pt}}%
+    \pgfpathlineto{\pgfpoint{2pt}{2pt}}%
+    \pgfpathmoveto{\pgfpoint{2pt}{0pt}}%
+  }%
+  \state{final}{%
+    \pgfpathlineto{\pgfpointdecoratedpathlast}%
+  }%
+}%
+\tikzset{lddbond/.style={decorate,decoration=ddbond}}%
+\tikzset{rddbond/.style={decorate,decoration={ddbond,mirror}}}%
+A scheme with transition states.
+
+\begin{rxnscheme}{Hydratisation}
+ \reactant[,carbonyl_A]{\chemfig{R_2C=O}}
+ \anywhere{above=of carbonyl_A}{\chemfig{H-[:-30]O-[:30]H}}
+ \arrow[,<=>]{\tiny slow}{}
+ \transition[,transition_A]{\chemfig{R_2C(-[2,,2,,densely dotted]\chemabove{O}{\delp}(-[:150]H)-[:30]H)-[:-30,1.15,,,lddbond]O-[6,,,,densely dotted]H-[,,,,densely dotted]\chemabove{A}{\delm}}}
+ \anywhere{below=of transition_A,,text width=3cm}{(general transition state, acid cat.)}
+ \arrow[,<=>,.7]{}{}
+ \reactant{\chemfig{R_2C(-[:60]\chemabove{O}{\fscrp}H_2)-[:-60]OH}}
+ \arrow[below right,<=>,.7]{$-\Hpl$}{}
+ \reactant[below right]{\chemfig{R_2C(-[:60]OH)-[:-60]OH}}
+ \arrow[below left,<=>,.7]{}{\ch{H2O}}
+ \reactant[below left,zw]{\chemfig{R_2C(-[:60]OH)-[:-60]O|\mch}}
+ \arrow[left,<=>,.7]{}{}
+ \transition[left,transition_B]{\chemfig{R_2C(-[2,,2,,densely dotted]O(-[:150]H-[4,,,,densely dotted]\chemabove{B}{\delp})-[:30]H)-[:-30,1.15,,,lddbond]\chemabove{O}{\delm}-[6,,,,draw=none]\phantom{H}}}
+ \anywhere{below=of transition_B,,text width=3cm}{(general transition state, base cat.)}
+ \arrow[left,<=>]{}{\tiny slow}
+ \reactant[left,carbonyl_B]{\chemfig{R_2C=O}}
+ \anywhere{above=of carbonyl_B}{\chemfig{H-[:-30]O-[:30]H}}
+\end{rxnscheme}
+
+For this example we first declare a style for the delocalized double bonds:
+\begin{beispiel}[code only]
+ \pgfdeclaredecoration{ddbond}{initial}{%
+   \state{initial}[width=2pt]{%
+     \pgfpathlineto{\pgfpoint{2pt}{0pt}}%
+     \pgfpathmoveto{\pgfpoint{1.5pt}{2pt}}%
+     \pgfpathlineto{\pgfpoint{2pt}{2pt}}%
+     \pgfpathmoveto{\pgfpoint{2pt}{0pt}}%
+   }%
+   \state{final}{%
+     \pgfpathlineto{\pgfpointdecoratedpathlast}%
+   }%
+ }%
+ \tikzset{lddbond/.style={decorate,decoration=ddbond}}%
+ \tikzset{rddbond/.style={decorate,decoration={ddbond,mirror}}}%
+\end{beispiel}
+Now the delocalized double bond can be used via \paket*{chemfig}'s fifth option
+(see the \paket{chemfig} manual):
+\begin{beispiel}[code only]
+ \chemfig{-[,,,,lddbond]-[,,,,rddbond]}
+\end{beispiel}
+\chemfig{-[,,,,lddbond]-[,,,,rddbond]}\par\medskip
+
+Then the whole code looks like follows:
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Hydratisation}
+  \reactant[,carbonyl_A]{\chemfig{R_2C=O}}
+  \anywhere{above=of carbonyl_A}{\chemfig{H-[:-30]O-[:30]H}}
+  \arrow[,<=>]{\tiny slow}{}
+  \transition[,transition_A]{\chemfig{R_2C(-[2,,2,,densely dotted]\chemabove{O}{\delp}(-[:150]H)-[:30]H)-[:-30,1.15,,,lddbond]O-[6,,,,densely dotted]H-[,,,,densely dotted]\chemabove{A}{\delm}}}
+  \anywhere{below=of transition_A,,text width=3cm}{(general transition state, acid cat.)}
+  \arrow[,<=>,.7]{}{}
+  \reactant{\chemfig{R_2C(-[:60]\chemabove{O}{\fscrp}H_2)-[:-60]OH}}
+  \arrow[below right,<=>,.7]{$-\Hpl$}{}
+  \reactant[below right]{\chemfig{R_2C(-[:60]OH)-[:-60]OH}}
+  \arrow[below left,<=>,.7]{}{\ch{H2O}}
+  \reactant[below left,zw]{\chemfig{R_2C(-[:60]OH)-[:-60]O|\mch}}
+  \arrow[left,<=>,.7]{}{}
+  \transition[left,transition_B]{\chemfig{R_2C(-[2,,2,,densely dotted]O(-[:150]H-[4,,,,densely dotted]\chemabove{B}{\delp})-[:30]H)-[:-30,1.15,,,lddbond]\chemabove{O}{\delm}-[6,,,,draw=none]\phantom{H}}}
+  \anywhere{below=of transition_B,,text width=3cm}{(general transition state, base cat.)}
+  \arrow[left,<=>]{\tiny langsam}{}
+  \reactant[left,carbonyl_B]{\chemfig{R_2C=O}}
+  \anywhere{above=of carbonyl_B}{\chemfig{H-[:-30]O-[:30]H}}
+ \end{rxnscheme}
+\end{beispiel}
+You can see that \cmd{anywhere} was used several times, either to place molecules
+or to label molecules.
+
+\section{Esterification}\label{sec:veresterung}
+\begin{rxnscheme}{Esterification}
+ \reactant{\chemfig{H-C(=[:60]O)-[:-60]O-H}}
+ \arrow[,-+>,1.5,protolysis]{\ch{H2SO4}}{\ch{HSO4-}}
+ \anywhere{below=of protolysis,,yshift=1em}{\tiny protolysis}
+ \mesomeric{
+   \reactant{\chemfig{H-@{a2}C(-[:60]O-H)(-[:30,.5,,,draw=none]{\fscrp})-[:-60]O-H}}
+   \marrow
+   \reactant{\chemfig{H-C(=[:60]\chemabove{O}{\fscrp}-H)-[:-60]O-H}}
+ }
+ \branch[below,,xshift=-5em]{
+   \arrow[below,<=>]{\chemfig{H-[:120]@{a1}O-[:60]CH_3}}{\tiny addition}
+   \reactant[below]{\chemfig{H-C(-[2]O-[:30]H)(-\chemabove{O}{\fscrp}(-[:60]CH_3)-[:-60]H)-[6]O-[:-30]H}\elmove{a1}{90:1.5cm}{a2}{0:3cm}}
+ }
+ \branch[left,,yshift=-3.5em]{
+   \arrow[left,<=>]{}{\tiny protolysis}
+ }
+ \reactant[left]{\chemfig{H-C(-[2]O-[:30]H)(-O-CH_3)-[@{b1}6]@{a3}\chemabove{O}{\hspace*{-4mm}\fscrp}(-[:-150]H)-[:-30]H}\elmove{b1}{0:5mm}{a3}{20:5mm}}
+ \arrow[below,<=>]{$- {\ch{H2O}}$}{\tiny elimination}
+ \mesomeric[below,,xshift=6em]{
+   \reactant{\chemfig{H-C(-[:60]O-H)(-[,.5,,,draw=none]{\fscrp})-[:-60]O-CH_3}}
+   \marrow
+   \reactant{\chemfig{H-C(=[:60]\chemabove{O}{\fscrp}-H)-[:-60]O-CH_3}}
+ }
+ \arrow[,-+>,1.5]{\ch{HSO4-}}{\ch{H2SO4}}
+ \reactant{\chemfig{H-C(=[:60]O)-[:-60]O-CH_3}}
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxn}{Esterification}
+  \reactant{\chemfig{H-C(=[:60]O)-[:-60]O-H}}
+  \arrow[,-+>,1.2,protolysis]{\ch{H2SO4}}{\ch{HSO4-}}
+  \anywhere{below=of protolysis,,yshift=1em}{\tiny protolysis}
+  \mesomeric{
+    \reactant{\chemfig{H-@{a2}C(-[:60]O-H)(-[:30,.5,,,draw=none]{\fscrp})-[:-60]O-H}}
+    \marrow
+    \reactant{\chemfig{H-C(=[:60]\chemabove{O}{\fscrp}-H)-[:-60]O-H}}
+  }
+  \branch[below,,xshift=-5em]{
+    \arrow[below,<=>]{\tiny addition}{\chemfig{H-[:120]@{a1}O-[:60]CH_3}}
+    \reactant[below]{
+      \chemfig{H-C(-[2]O-[:30]H)(-\chemabove{O}{\fscrp}(-[:60]CH_3)-[:-60]H)-[6]O-[:-30]H}
+      \elmove{a1}{90:1.5cm}{a2}{0:3cm}
+    }
+  }
+  \branch[left,,yshift=-3.5em]{
+    \arrow[left,<=>]{}{\tiny protolysis}
+  }
+  \reactant[left]{
+    \chemfig{H-C(-[2]O-[:30]H)(-O-CH_3)-[@{b1}6]@{a3}\chemabove{O}{\hspace*{-4mm}\fscrp}(-[:-150]H)-[:-30]H}
+    \elmove{b1}{0:5mm}{a3}{20:5mm}
+  }
+  \arrow[below,<=>]{$- {\ch{H2O}}$}{\tiny elimination}
+  \mesomeric[below,,xshift=6em]{
+    \reactant{\chemfig{H-C(-[:60]O-H)(-[,.5,,,draw=none]{\fscrp})-[:-60]O-CH_3}}
+    \marrow
+    \reactant{\chemfig{H-C(=[:60]\chemabove{O}{\fscrp}-H)-[:-60]O-CH_3}}
+  }
+  \arrow[,-+>,1.2]{\ch{HSO4-}}{\ch{H2SO4}}
+  \reactant{\chemfig{H-C(=[:60]O)-[:-60]O-CH_3}}
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Electrophilic Addition}\label{sec:elektrophile_addition}
+This scheme forms a circle.
+\begin{rxnscheme}{Electrophilic Addition}
+ \setarrowlength{3em}
+ \reactant{\chemfig{>[:-20]C(<[:40])=[6]C(<[:-130])<[:-20]}}
+ \chemand[,plus]
+ \reactant{\chemfig{\lewis{246,Br}-\lewis{026,Br}}}
+ \arrow[plus.-90,<=>]{\footnotesize fast}{}
+ \reactant[-90,attack]{\chemfig{>[:-20]C(<[:40])=[@{db}6]C(<[:-130])<[:-20]}}
+ \anywhere{right=of attack}{
+   \chemfig{@{Br1}\lewis{246,Br}-[@{b2}]@{Br2}\lewis{026,Br}}
+   \elmove{db}{20:5mm}{Br1}{135:5mm}
+   \elmove{b2}{-120:5mm}{Br2}{-120:5mm}
+ }
+ % to the left:
+ \arrow[attack.-135,<=>,2]{$- {\ch{Br-}}$}{\footnotesize slow}
+ \reactant[-135,carbenium_a]{\vflipnext\chemfig{-[:-30]\chembelow{C}{\fscrp}(-[:30])-[6]C(<[:-150])(<:[:-100])-[:-30]\lewis{137,Br}}}
+ \anywhere{below=of carbenium_a}{\footnotesize carbenium ion}
+ \arrow[,<<=>]{}{}
+ \reactant[,bromonium]{\chemfig{>:[:-60]C?(<[:160])-[6]C(<[:-110])(<:[:-150])-[:30]\lewis{17,Br}?-[4,.5,,,draw=none]{\fscrp}}}
+ \anywhere{below=of bromonium,,yshift=.35em}{\footnotesize bromonium ion}
+ % to the right:
+ \arrow[attack.-45,<=>,2]{\footnotesize slow}{$- {\ch{Br-}}$}
+ \reactant[-45,carbenium_b]{\chemfig{-[:-30]\chemabove{C}{\fscrp}(-[:30])-[6]C(<:[:-150])(<[:-100])-[:-30]\lewis{157,Br}}}
+ \anywhere{below=of carbenium_b}{\footnotesize carbenium ion}
+ \arrow[left,<<=>]{}{}
+ \mCsetup{reset}
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Electrophilic Addition}
+  \setarrowlength{3em}
+  \reactant{\chemfig{>[:-20]C(<[:40])=[6]C(<[:-130])<[:-20]}}
+  \chemand[,plus]
+  \reactant{\chemfig{\lewis{246,Br}-\lewis{026,Br}}}
+  \arrow[plus.-90,<=>]{\footnotesize fast}{}
+  \reactant[-90,attack]{\chemfig{>[:-20]C(<[:40])=[@{db}6]C(<[:-130])<[:-20]}}
+  \anywhere{right=of attack}{
+    \chemfig{@{Br1}\lewis{246,Br}-[@{b2}]@{Br2}\lewis{026,Br}}
+    \elmove{db}{20:5mm}{Br1}{135:5mm}
+    \elmove{b2}{-120:5mm}{Br2}{-120:5mm}
+  }
+  % to the left:
+  \arrow[attack.-135,<=>,2]{$- {\ch{Br-}}$}{\footnotesize slow}
+  \reactant[-135,carbenium_a]{\vflipnext\chemfig{-[:-30]\chembelow{C}{\fscrp}(-[:30])-[6]C(<[:-150])(<:[:-100])-[:-30]\lewis{137,Br}}}
+  \anywhere{below=of carbenium_a}{\footnotesize carbenium ion}
+  \arrow[,<<=>]{}{}
+  \reactant[,bromonium]{\chemfig{>:[:-60]C?(<[:160])-[6]C(<[:-110])(<:[:-150])-[:30]\lewis{17,Br}?-[4,.5,,,draw=none]{\fscrp}}}
+  \anywhere{below=of bromonium,,yshift=.35em}{\footnotesize bromonium ion}
+  % to the right:
+  \arrow[attack.-45,<=>,2]{\footnotesize slow}{$- {\ch{Br-}}$}
+  \reactant[-45,carbenium_b]{\chemfig{-[:-30]\chemabove{C}{\fscrp}(-[:30])-[6]C(<:[:-150])(<[:-100])-[:-30]\lewis{157,Br}}}
+  \anywhere{below=of carbenium_b}{\footnotesize carbenium ion}
+  \arrow[left,<<=>]{}{}
+  \mCsetup{reset}
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Activation of Fatty Acids}\label{sec:activation_fatty_acid}
+\begin{rxnscheme}{Activation of Fatty Acids}
+ \reactant[,ATP]{\chemfig{\chemabove{O}{\hspace*{-5mm}\fscrm}-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-@{O1}O-[@{b1}]@{P}P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-CH_2-[6,1.5,1](-[6,.5])(-[:20,1.3]O?[a])<[7](-[2,.5])(-[6]OH)-[,,,,line width=3pt](-[2,.5])(-[6]OH)>[1]?[a](-[6,.5])-[2,1.5]N?[b]-[:18]([:30]*6(-N=-N=(-NH_2)-=))-[:90]-[:162]N=^[:-126]?[b]}}
+ \anywhere{below right=of ATP,,xshift=-4em,yshift=3em}{\bfseries ATP}
+ \arrow[below,,1.5]{}{\chemname{\chemfig{R-C(=[:-60]O)-[:60]@{O2}O-[@{b2}]H}}{fatty acid}}
+ \branch[on chain=going below]{
+   \reactant[,pyrophosphat]{
+     \chemfig{\chemabove{O}{\hspace*{-5mm}\fscrm}-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-\chemabove{O}{\hspace*{5mm}\fscrm}}
+     \elmove{b1}{100:1cm}{O1}{90:5mm}
+     \elmove{O2}{135:1cm}{P}{-135:1cm}
+     \elmove{b2}{-90:5mm}{O2}{-60:5mm}
+     }
+   \anywhere{below=of pyrophosphat}{pyrophosphate PP$_\text{i}$}
+   \chemand
+   \reactant[,acyl-amp]{\chemfig{R-@{C}C(=[:-60]O)-[@{b3}:60]@{O3}O-P(-[6]\chembelow{O}{\fscrm})(=[2]O)-O-CH_2-[6,,1,1]r|ibos|e-[2,1.05,3,1]a|denine}}
+   \anywhere{below=of acyl-amp}{\bfseries acyl-AMP}
+ }
+ \branch[on chain=going below,,xshift=-8em]{
+   \arrow[below]{\ch{H2O}}{}
+   \reactant[below,Pi]{2~\chemfig{HO-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O}}
+   \anywhere{below right=of Pi}{P$_\text{i}$}
+ }
+ \branch[,,xshift=4em]{
+   \arrow[below,-+>]{\chemfig{CoA-@{S}S-[@{b4}:-60]H}}{AMP}
+   \reactant[below,acyl-SCoA]{
+     \chemfig{R-C(=[:-60]O)-[:60]S-CoA}
+     \elmove{S}{45:3cm}{C}{-120:2cm}
+     \elmove{b3}{135:5mm}{O3}{110:7mm}
+     \elmove{b4}{-120:7mm}{S}{-100:5mm}
+   }
+   \anywhere{below=of acyl-SCoA}{acyl-SCoA}
+ }
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Activation of Fatty Acids}
+  \reactant[,ATP]{\chemfig{\chemabove{O}{\hspace*{-5mm}\fscrm}-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-@{O1}O-[@{b1}]@{P}P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-CH_2-[6,1.5,1](-[6,.5])(-[:20,1.3]O?[a])<[7](-[2,.5])(-[6]OH)-[,,,,line width=3pt](-[2,.5])(-[6]OH)>[1]?[a](-[6,.5])-[2,1.5]N?[b]-[:18]([:30]*6(-N=-N=(-NH_2)-=))-[:90]-[:162]N=^[:-126]?[b]}}
+  \anywhere{below right=of ATP,,xshift=-4em,yshift=3em}{\bfseries ATP}
+  \arrow[below,,1.5]{\chemname{\chemfig{R-C(=[:-60]O)-[:60]@{O2}O-[@{b2}]H}}{fatty acid}}{}
+  \branch[on chain=going below]{
+    \reactant[,pyrophosphat]{
+      \chemfig{\chemabove{O}{\hspace*{-5mm}\fscrm}-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-\chemabove{O}{\hspace*{5mm}\fscrm}}
+      \elmove{b1}{100:1cm}{O1}{90:5mm}
+      \elmove{O2}{135:1cm}{P}{-135:1cm}
+      \elmove{b2}{-90:5mm}{O2}{-60:5mm}
+      }
+    \anywhere{below=of pyrophosphat}{pyrophosphate PP$_\text{i}$}
+    \chemand
+    \reactant[,acyl-amp]{\chemfig{R-@{C}C(=[:-60]O)-[@{b3}:60]@{O3}O-P(-[6]\chembelow{O}{\fscrm})(=[2]O)-O-CH_2-[6,,1,1]r|ibos|e-[2,1.05,3,1]A|denine}}
+    \anywhere{below=of acyl-amp}{\bfseries acyl-AMP}
+  }
+  \branch[on chain=going below,,xshift=-8em]{
+    \arrow[below]{\ch{H2O}}{}
+    \reactant[below,Pi]{2~\chemfig{HO-P(=[2]O)(-[6]\chembelow{O}{\fscrm})-O}}
+    \anywhere{below right=of Pi}{P$_\text{i}$}
+  }
+  \branch[,,xshift=4em]{
+    \arrow[below,-+>]{\chemfig{CoA-@{S}S-[@{b4}:-60]H}}{AMP}
+    \reactant[below,acyl-SCoA]{
+      \chemfig{R-C(=[:-60]O)-[:60]S-CoA}
+      \elmove{S}{135:2cm}{C}{-135:1cm}
+      \elmove{b3}{-45:5mm}{O3}{-70:7mm}
+      \elmove{b4}{-120:7mm}{S}{-100:5mm}
+    }
+    \anywhere{below=of acyl-SCoA}{acyl-SCoA}
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Change the layout with \TikZ}\label{sec:tikz_layout}
+\begin{rxnscheme}{Change the layout with \TikZ}
+  \colorlet{mCgreen}{green!50!gray}
+  \colorlet{mCblue}{cyan!50!gray}
+  \colorlet{mCred}{magenta!50!gray}
+  \tikzset{reactant/.style={draw=#1,fill=#1!10,minimum width=.8\textwidth,inner sep=1em,rounded corners}}
+  \mCsetup{arrowlength=3em,arrowline=very thick}
+  \reactant[,,reactant=mCgreen]{
+    \chemname{\chemfig{Alky|l--[6](-[4,,,2]Acy|l)-[6]-O-P(=[2]O)(-[6]O|\mch)-O-[:-30]-[:30]-[:-30]NH_2}}{\bfseries Phosphatidylethanolamine}
+  }
+  \arrow[below]{\iupac{\N\-acyl\|transferase}}{}
+  \reactant[below,,reactant=mCblue]{
+    \chemname{\chemfig{Alky|l--[6](-[4,,,2]Acy|l)-[6]-O-P(=[2]O)(-[6]O|\mch)-O-[:-30]-[:30]-[:-30]\chembelow{N}{H}-[:30](=[2]O)-[:-30]-[:30]-[:-30]-[:30]=_-[:-30]-[:30]=_-[:-60]-[::-60]=_[:180]-[::-30]-[::60]=_[:180]-[::-30]-[::60]-[::-60]-[::60]-[6]}}{\bfseries\iupac{\N\-arachidonoyl\-PE}}
+  }
+  \arrow[below]{Phospholipase D}{}
+  \reactant[below,,reactant=mCred]{
+    \chemname{\chemfig{HO-[:-30]-[:30]-[:-30]\chembelow{N}{H}-[:30](=[2]O)-[:-30]-[:30]-[:-30]-[:30]=_-[:-30]-[:30]=_-[:-60]-[::-60]=_[:180]-[::-30]-[::60]=_[:180]-[::-30]-[::60]-[::-60]-[::60]-[6]}}{\bfseries Anandamide}
+  }
+  \mCsetup{reset}
+\end{rxnscheme}
+
+This is an example for the usage of the \code{<tikz>} option. Please take a closer
+look at lines \numlist{5;7;11;15}.
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Change the layout with \TikZ}
+  \colorlet{mCgreen}{green!50!gray}
+  \colorlet{mCblue}{cyan!50!gray}
+  \colorlet{mCred}{magenta!50!gray}
+  !!\tikzset{reactant/.style={draw=#1,fill=#1!10,minimum width=.8\textwidth,inner sep=1em,rounded corners}}!!
+  \mCsetup{arrowlength=3em,arrowline=very thick}
+  \reactant[,,!!reactant=mCgreen!!]{
+    \chemname{\chemfig{Alky|l--[6](-[4,,,2]Acy|l)-[6]-O-P(=[2]O)(-[6]O|\mch)-O-[:-30]-[:30]-[:-30]NH_2}}{\bfseries Phosphatidylethanolamine}
+  }
+  \arrow[below]{}{\iupac{\N-acyl\|transferase}}
+  \reactant[below,,!!reactant=mCblue!!]{
+    \chemname{\chemfig{Alky|l--[6](-[4,,,2]Acy|l)-[6]-O-P(=[2]O)(-[6]O|\mch)-O-[:-30]-[:30]-[:-30]\chembelow{N}{H}-[:30](=[2]O)-[:-30]-[:30]-[:-30]-[:30]=_-[:-30]-[:30]=_-[:-60] -[::-60]=_[:180]-[::-30]-[::60]=_[:180]-[::-30]- [::60]-[::-60]-[::60]-[6]}}{\bfseries\iupac{\N\-arachidonoyl\-PE}}
+  }
+  \arrow[below]{}{Phospholipase D}
+  \reactant[below,,!!reactant=mCred!!]{
+    \chemname{\chemfig{HO-[:-30]-[:30]-[:-30]\chembelow{N}{H}-[:30](=[2]O)-[:-30]-[:30]-[:-30]-[:30]=_-[:-30]-[:30]=_-[:-60] -[::-60]=_[:180]-[::-30]-[::60]=_[:180]-[::-30]- [::60]-[::-60]-[::60]-[6]}}{\bfseries Anandamide}
+  }
+  \mCsetup{reset}
+ \end{rxnscheme}
+\end{beispiel}
+
+\section{Claisen-Kondensation}
+\begin{rxnscheme}{Claisen-Kondensation}
+ \colorlet{mCred}{red!50!gray}
+ \setatomsep{1.5em}
+ % Ergebnis:
+ \branch[,one,draw=mCred,fill=mCred!10,rounded corners,inner sep=.5em]{
+   \reactant{\chemfig{[:30]-(=[2]O)-[:-30]O--[:-30]}}
+   \chemand
+   \reactant{\chemfig{[:30]-(=[2]O)-[:-30]O--[:-30]}}
+   \arrow[,,2]{\ch{NaOEt}, \ch{EtOH}}{}
+   \reactant{\chemfig{[:30]-(=[2]O)-[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+ }
+ % Mechanismus:
+ \branch[-90,,xshift=-13.5em]{
+   \arrow[-90,<<=>]{\ch{^-OEt}}{}
+ }
+ \mesomeric[-90,two,xshift=4.5em]{
+   \reactant{\chemfig{[:30](-[:150,.3,,,draw=none]@{C1}\fscrm)-(=[2]O)-[:-30]O--[:-30]}}
+   \marrow
+   \reactant{\chemfig{[:30]=(-[2]O|\mch)-[:-30]O--[:-30]}}
+ }
+ \chemand
+ \reactant{\ch{EtOH}}
+ \branch[two.-90,three,xshift=-5.5em]{
+   \arrow[-90,<=>,,,both]{\chemfig[][scale=.7]{[:30]-@{C2}(=[@{b1}2]O@{O1})-[:-30]O--[:-30]}}{}
+ }
+ \reactant[three.-90]{\chemfig{-(-[@{b2}2]@{O2}O|\mch)(-[6]-[:-30](=[6]O)-[:30]O-[:-30]-[:30])-[@{b3}]@{O3}O-[:30]-[:-30]}}
+ \arrow[,<=>]{}{}
+ \reactant[,four]{\chemfig{[:30]-(=[2]O)-[:-30]@{C3}(-[:-120]H)(-[@{b4}:-60]H@{H})-(=[2]O)-[:-30]O--[:-30]}}
+ \chemand
+ \reactant{\chemfig{\mch @{O4}OEt}}
+ \arrow[four.-90]{}{}
+ \mesomeric[-90]{
+   \reactant{\chemfig{[:30]-(=[2]O)-[:-30]=(-[2]O|\mch)-[:-30]O--[:-30]}}
+   \marrow
+   \reactant{\chemfig{[:30]-(=[2]O)-[:-30](-[6,.3,,,draw=none]\fscrm)-(=[2]O)-[:-30]O--[:-30]}}
+   \marrow
+   \reactant{\chemfig{[:30]-(-[2]O|\mch)=[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+ }
+ \arrow[-90]{\Hpl, \ch{H2O}}{}
+ \reactant[-90]{\chemfig{[:30]-(=[2]O)-[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+ \anywhere{one.0}{
+   \elmove{C1}{-100:2cm}{C2}{-90:2cm}
+   \elmove{b1}{10:5mm}{O1}{0:5mm}
+   \elmove{O2}{180:5mm}{b2}{180:5mm}
+   \elmove{b3}{80:5mm}{O3}{90:5mm}
+   \elmove{b4}{0:5mm}{C3}{0:7mm}
+   \elmove{O4}{-90:1cm}{H}{-45:1cm}
+ }
+\end{rxnscheme}
+
+\begin{beispiel}[code only]
+ \begin{rxnscheme}{Claisen-Kondensation}
+  \colorlet{mCred}{red!50!gray}
+  \setatomsep{1.5em}
+  % Ergebnis:
+  \branch[,one,draw=mCred,fill=mCred!10,rounded corners,inner sep=.5em]{
+    \reactant{\chemfig{[:30]-(=[2]O)-[:-30]O--[:-30]}}
+    \chemand
+    \reactant{\chemfig{[:30]-(=[2]O)-[:-30]O--[:-30]}}
+    \arrow[,,2]{\ch{NaOEt}, \ch{EtOH}}{}
+    \reactant{\chemfig{[:30]-(=[2]O)-[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+  }
+  % Mechanismus:
+  \branch[-90,,xshift=-13.5em]{
+    \arrow[-90,<=>]{\ch{^-OEt}}{}
+  }
+  \mesomeric[-90,two,xshift=4.5em]{
+    \reactant{\chemfig{[:30](-[:150,.3,,,draw=none]@{C1}\fscrm)-(=[2]O)-[:-30]O--[:-30]}}
+    \marrow
+    \reactant{\chemfig{[:30]=(-[2]O|\mch)-[:-30]O--[:-30]}}
+  }
+  \chemand
+  \reactant{\ch{EtOH}}
+  \branch[two.-90,three,xshift=-5.5em]{
+    \arrow[-90,<=>,,,both]{\chemfig[][scale=.7]{[:30]-@{C2}(=[@{b1}2]O@{O1})-[:-30]O--[:-30]}}{}
+  }
+  \reactant[three.-90]{\chemfig{-(-[@{b2}2]@{O2}O|\mch)(-[6]-[:-30](=[6]O)-[:30]O-[:-30]-[:30])-[@{b3}]@{O3}O-[:30]-[:-30]}}
+  \arrow[,<=>]{}{}
+  \reactant[,four]{\chemfig{[:30]-(=[2]O)-[:-30]@{C3}(-[:-120]H)(-[@{b4}:-60]H@{H})-(=[2]O)-[:-30]O--[:-30]}}
+  \chemand
+  \reactant{\chemfig{\mch @{O4}OEt}}
+  \arrow[four.-90]{}{}
+  \mesomeric[-90]{
+    \reactant{\chemfig{[:30]-(=[2]O)-[:-30]=(-[2]O|\mch)-[:-30]O--[:-30]}}
+    \marrow
+    \reactant{\chemfig{[:30]-(=[2]O)-[:-30](-[6,.3,,,draw=none]\fscrm)-(=[2]O)-[:-30]O--[:-30]}}
+    \marrow
+    \reactant{\chemfig{[:30]-(-[2]O|\mch)=[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+  }
+  \arrow[-90]{\Hpl, \ch{H2O}}{}
+  \reactant[-90]{\chemfig{[:30]-(=[2]O)-[:-30]-(=[2]O)-[:-30]O--[:-30]}}
+  \anywhere{one.0}{
+    \elmove{C1}{-100:2cm}{C2}{-90:2cm}
+    \elmove{b1}{10:5mm}{O1}{0:5mm}
+    \elmove{O2}{180:5mm}{b2}{180:5mm}
+    \elmove{b3}{80:5mm}{O3}{90:5mm}
+    \elmove{b4}{0:5mm}{C3}{0:7mm}
+    \elmove{O4}{-90:1cm}{H}{-45:1cm}
+  }
+ \end{rxnscheme}
+\end{beispiel}
+
+
+\section{Extensive Synthesis}\label{sec:tikzsynthese}
+As last example we can create extensive syntheses, using the \cmd{merge} command.
+\begin{rxnscheme}[,,,.8]{Extensive Synthesis}
+ \setatomsep{1.5em}
+ \branch[,start_left]{
+   \reactant{\chemfig{=_[::30]-[::-60]-[::60](-[::-60])(-[::120])-[::0]OH}}
+   \arrow[below]{\ch{HBr}}{}
+   \reactant[below]{\chemfig{Br-[::30]-[::-60]=_[::60](-[::-60])-[::60]}}
+ }
+ \branch[right=of start_left,start_center,yshift=1em]{
+   \reactant{\chemname{\chemfig[][scale=.8]{**6(--(-SO_2Cl)---(-)-)}}{tosyle chloride}}
+   \arrow[below]{\ch{NaOH}}{\ch{Zn}}
+   \reactant[below]{\chemfig[][scale=.8]{**6(--(-SO_2Na)---(-)-)}}
+ }
+ \branch[right=of start_center,start_right,xshift=3em,yshift=-10em]{
+   \reactant{\chemname{\chemfig{-[::30](-[::60])=_[::-60]-[::60]COOH}}{\iupac{3\-methyl\-2\-butenoic acid}}}
+   \arrow[below]{\ch{CH3OH}}{}
+   \reactant[below]{\chemfig{-[::30](-[::60])=_[::-60]-[::60]CO_2CH_3}}
+ }
+ \branch[below=of start_left,target_one,xshift=5em,yshift=-5em]{
+   \reactant{\chemfig[][scale=.8]{**6(--(-SO_2-[:30]-[::-60]=_[::60](-[::60])-[::-60])---(-)-)}}
+ }
+ \branch[below=of target_one,target_two,xshift=6em,yshift=-6em]{
+   \mesomeric{\chemfig[][scale=.8]{-[::30](-[::60])=^[::-60]-[::60](-[::60]S(=[::90]O)(=[::-90]O)-[::0]**6(---(-)---))-[::-60](-[::0])(-[::-120])-[::60](-[::60,.5,,,white]\fminus)-[::-60]CO_2CH_3}}
+   \arrow[below,,.5]{}{}
+   \arrow[below,,.5]{\ch{KOH}}{}
+   \reactant[below]{\chemname{\chemfig{-[::-30](-[::-60])=^[::60]>[::-60](-[::90,1.2])-[::30,1.2](-[::120,1.2](-[::-60])-[::0])<:[::-30]COOH}}{\iupac{\trans\-chrysanthemum acid}}}
+ }
+ \merge{target_one}{start_left}{start_center}
+ \merge[\ch{NaOCH3}]{target_two}{target_one}{start_right}
+\end{rxnscheme}
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[,,,.8]{Extensive Synthesis}
+  \setatomsep{1.5em}
+  \branch[,start_left]{
+    \reactant{\chemfig{=_[::30]-[::-60]-[::60](-[::-60])(-[::120])-[::0]OH}}
+    \arrow[below]{\ch{HBr}}{}
+    \reactant[below]{\chemfig{Br-[::30]-[::-60]=_[::60](-[::-60])-[::60]}}
+  }
+  \branch[right=of start_left,start_center,yshift=1em]{
+    \reactant{\chemname{\chemfig[][scale=.8]{**6(--(-SO_2Cl)---(-)-)}}{tosyle chloride}}
+    \arrow[below]{\ch{NaOH}}{\ch{Zn}}
+    \reactant[below]{\chemfig[][scale=.8]{**6(--(-SO_2Na)---(-)-)}}
+  }
+  \branch[right=of start_center,start_right,xshift=3em,yshift=-10em]{
+    \reactant{\chemname{\chemfig{-[::30](-[::60])=_[::-60]-[::60]COOH}}{\iupac{3\-methyl\-2\-butenoic acid}}}
+    \arrow[below]{\ch{CH3OH}}{}
+    \reactant[below]{\chemfig{-[::30](-[::60])=_[::-60]-[::60]CO_2CH_3}}
+  }
+  \branch[below=of start_left,target_one,xshift=5em,yshift=-5em]{
+    \reactant{\chemfig[][scale=.8]{**6(--(-SO_2-[:30]-[::-60]=_[::60](-[::60])-[::-60])---(-)-)}}
+  }
+  \branch[below=of target_one,target_two,xshift=6em,yshift=-6em]{
+    \mesomeric{\chemfig[][scale=.8]{-[::30](-[::60])=^[::-60]-[::60](-[::60]S(=[::90]O)(=[::-90]O)-[::0]**6(---(-)---))-[::-60](-[::0])(-[::-120])-[::60](-[::60,.5,,,white]\fminus)-[::-60]CO_2CH_3}}
+    \arrow[below,,.5]{}{}
+    \arrow[below,,.5]{\ch{KOH}}{}
+    \reactant[below]{\chemname{\chemfig{-[::-30](-[::-60])=^[::60]>[::-60](-[::90,1.2])-[::30,1.2](-[::120,1.2](-[::-60])-[::0])<:[::-30]COOH}}{\iupac{\trans\-chrysanthemum acid}}
+  }
+  \merge{target_one}{start_left}{start_center}
+  \merge[\ch{NaOCH3}]{target_two}{target_one}{start_right}
+ \end{rxnscheme}
+\end{beispiel}
+
+\end{document}
\ No newline at end of file
diff --git a/obsolete/macros/latex/contrib/mychemistry/mychemistry.sty b/obsolete/macros/latex/contrib/mychemistry/mychemistry.sty
new file mode 100644
index 0000000000..089ac37b85
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/mychemistry.sty
@@ -0,0 +1,1557 @@
+% --------------------------------------------------------------------------
+% the MYCHEMISTRY package
+%
+%   create reaction schemes with LaTeX and chemfig
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://www.bitbucket.org/cgnieder/mychemistry
+% E-Mail: contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011--2012 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.
+%
+% This work consists of the files mychemistrysty, mychemistry_en.tex,
+% README and the derived file mychemistry_en.pdf.
+% --------------------------------------------------------------------------
+\ProvidesPackage{mychemistry}[2012/12/19 v1.99b create reaction schemes with LaTeX and chemfig]
+\RequirePackage{etoolbox,float,xkeyval,chemfig,chemmacros}
+\usetikzlibrary{
+  arrows,
+  positioning,
+  decorations.pathmorphing,
+  shapes,
+  calc,
+  matrix,
+  chains,
+  scopes,
+  intersections}
+
+% --------------------------------------------------------------------------
+% Tools
+\newif\ifmCh@strict
+\newif\ifmCh@draft
+\def\mCh@if@strict{%
+  \ifmCh@strict\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi}
+
+\def\mCh@error#1#2{%
+  \mCh@if@strict
+    {\PackageError{mychemistry}{#1}{#2}}
+    {\PackageWarning{mychemistry}{#1}{#2}}}
+
+\def\mCh@strict@error#1#2{%
+  \begingroup
+    \mCh@stricttrue
+    \mCh@error{#1}{#2}%
+  \endgroup}
+
+\def\mCh@def#1{%
+  \ifdef{#1}{%
+    \mCh@strict@error{already defined}{mychemistry tries to define \string#1 but
+      it seems it is already defined. Please contact the author.}%
+      \@gobble
+  }{\def#1}}
+
+% "variablen" definieren
+\mCh@def\mCh@strip@bs{\expandafter\@gobble\string}
+\mCh@def\mCh@ifis@variable#1#2#3{%
+  \ifcsdef{mCh@variable@\mCh@strip@bs#1}
+    {#2}
+    {\mCh@error{variable \string#1 undefined}{}#3}}
+\mCh@def\mCh@new@variable#1{%
+  \ifcsdef{mCh@variable@\mCh@strip@bs#1}
+    {\mCh@error{variable \string#1 already defined. I'm doing nothing!}{}}
+    {\csdef{mCh@variable@\mCh@strip@bs#1}{}\csdef{mCh@\mCh@strip@bs#1}{}}}
+\mCh@def\mCh@set@variable#1#2{%
+  \mCh@ifis@variable{#1}{\csdef{mCh@\mCh@strip@bs#1}{#2}}{\@gobble}}
+\mCh@def\mCh@xset@variable#1#2{%
+  \mCh@ifis@variable{#1}{\csedef{mCh@\mCh@strip@bs#1}{#2}}{\@gobble}}
+\mCh@def\mCh@clear@variable#1{%
+  \mCh@ifis@variable{#1}{\csdef{mCh@\mCh@strip@bs#1}{}}{}}
+\mCh@def\mCh@let@variable#1#2{%
+  \mCh@ifis@variable{#1}{\mCh@ifis@variable{#2}
+    {\csletcs{mCh@\mCh@strip@bs#1}{mCh@\mCh@strip@bs#2}}{}}{}}
+\mCh@def\mCh@empty@variable#1{%
+  \mCh@ifis@variable{#1}{\cslet{mCh@\mCh@strip@bs#1}\@empty}{}}
+\mCh@def\mCh@ifeq@variable#1#2#3#4{%
+  \mCh@ifis@variable{#1}{\mCh@ifis@variable{#2}
+    {\ifcsequal{mCh@\mCh@strip@bs#1}{mCh@\mCh@strip@bs#2}{#3}{#4}}{}}{}}
+\mCh@def\mCh@ifempty@variable#1#2#3{%
+  \ifcsequal{mCh@\mCh@strip@bs#1}{@empty}{#2}{#3}}
+
+\mCh@new@variable\true
+\mCh@new@variable\false
+
+\mCh@set@variable\true{true}
+\mCh@set@variable\false{false}
+
+% Optional Argument Analysis
+% is #2 part of #1? (inspired by \CF@if@instr by Christian Tellechea)
+\mCh@def\mCh@if@instr#1#2{%
+  \def\mCh@if@instr@i##1#2##2\@nil{%
+    \ifstrempty{##2}{\@secondoftwo}{\@firstoftwo}}%
+  \mCh@if@instr@i#1\@@nil#2\@nil
+}
+
+\mCh@new@variable\firstarg
+\mCh@new@variable\secondarg
+\mCh@new@variable\thirdarg
+
+% Am ersten , splitten, #1 in #3 speichern, #2 in \mCh@remainargs
+% (das Makro ist eine Kopie von \CF@analyze@movearg in chemfig.tex von Christian Tellechea)
+\mCh@def\mCh@splitfirst#1,#2\@nil#3{%
+  \def#3{#1}\def\mCh@remainargs{#2}%
+}
+
+% ein durch , in 3 Teile getrenntes Argument splitten
+% (das Makro ist eine Abwandlung von \CF@analyze@movearg in chemfig.tex von Christian Tellechea)
+\mCh@def\mCh@splitarg#1{%
+  \mCh@if@instr{#1}{,}
+    {\expandafter\mCh@splitfirst#1\@nil\mCh@firstarg}
+    {\mCh@set@variable\firstarg{#1}}%
+  \expandafter\mCh@if@instr\expandafter{\mCh@remainargs}{,}
+    {\expandafter\mCh@splitfirst\mCh@remainargs\@nil\mCh@secondarg}{\expandafter\mCh@set@variable\expandafter\secondarg\expandafter{\mCh@remainargs}}%
+  \ifx\mCh@remainargs\mCh@secondarg
+    \mCh@empty@variable\thirdarg
+  \else
+    \expandafter\mCh@set@variable\expandafter\thirdarg\expandafter{\mCh@remainargs}%
+  \fi
+}
+
+% --------------------------------------------------------------------------
+% options
+\define@key[MC]{mychemistry.sty}{strict}{\mCh@stricttrue}
+\DeclareOptionX[MC]{strict}{\mCh@stricttrue}
+
+\define@key[MC]{mychemistry.sty}{draft}{\mCh@stricttrue\mCh@drafttrue}
+\DeclareOptionX[MC]{draft}{\mCh@stricttrue\mCh@drafttrue}
+
+\define@key[MC]{mychemistry.sty}{final}{\mCh@strictfalse\mCh@draftfalse}
+\DeclareOptionX[MC]{final}{\mCh@strictfalse\mCh@draftfalse}
+
+\mCh@new@variable\rs@placement
+\mCh@new@variable\rs@currentplacement
+
+\mCh@set@variable\rs@placement{hpt}
+\mCh@let@variable\rs@currentplacement\rs@placement
+
+\define@key[MC]{mychemistry.sty}{placement}{%
+  \mCh@set@variable\rs@placement{#1}}
+
+\ProcessOptionsX[MC]
+
+% --------------------------------------------------------------------------
+% language settings
+\mCh@new@variable\rs@name
+\mCh@set@variable\rs@name{Reaction scheme}
+
+\RequirePackage{translations}
+\NewTranslation{English} {reaction-scheme-(caption-title)} {Reaction scheme}
+\NewTranslation{French}  {reaction-scheme-(caption-title)} {Sch\'{e}ma r\'{e}actionnel}
+\NewTranslation{German}  {reaction-scheme-(caption-title)} {Reaktionsschema}
+\NewTranslation{Italian} {reaction-scheme-(caption-title)} {Reazione Scheme}
+\NewTranslation{Spanish} {reaction-scheme-(caption-title)} {Esquema de Reacci\'{o}n}
+\mCh@set@variable\rs@name{\GetTranslation{reaction-scheme-(caption-title)}}
+
+
+% --------------------------------------------------------------------------
+% Direction Analysis
+% Richtungen:
+\mCh@new@variable\r
+\mCh@new@variable\ar
+\mCh@new@variable\a
+\mCh@new@variable\al
+\mCh@new@variable\l
+\mCh@new@variable\br
+\mCh@new@variable\b
+\mCh@new@variable\bl
+
+\mCh@set@variable\r{right}
+\mCh@set@variable\ar{above right}
+\mCh@set@variable\a{above}
+\mCh@set@variable\al{above left}
+\mCh@set@variable\l{left}
+\mCh@set@variable\br{below right}
+\mCh@set@variable\b{below}
+\mCh@set@variable\bl{below left}
+
+\mCh@new@variable\vert@i
+\mCh@new@variable\vert@ii
+\mCh@new@variable\vert@iii
+
+\mCh@set@variable\vert@i{90}
+\mCh@set@variable\vert@ii{-90}
+\mCh@set@variable\vert@iii{270}
+
+% Richtung in Bezug auf node oder nicht?
+\mCh@new@variable\direction
+
+\mCh@def\mCh@split@angle#1.#2\@nil#3{%
+  \def#3{#1}\mCh@set@variable\direction{#2}}
+\mCh@def\mCh@wowo@node#1{%
+  \mCh@if@instr{#1}{.}
+    {\expandafter\mCh@split@angle#1\@nil\mCh@referred@node}
+    {\mCh@set@variable\direction{#1}}}
+
+% Winkel bestimmen:
+\mCh@new@variable\angle
+\mCh@new@variable\referred@node
+
+\mCh@def\mCh@analyze@angle#1{%
+  \mCh@empty@variable\angle
+  \mCh@empty@variable\referred@node
+  \mCh@wowo@node{#1}%
+  \mCh@ifeq@variable\direction\r  {\mCh@set@variable\angle{0}}{}%
+  \mCh@ifeq@variable\direction\ar {\mCh@set@variable\angle{45}}{}%
+  \mCh@ifeq@variable\direction\a  {\mCh@set@variable\angle{90}}{}%
+  \mCh@ifeq@variable\direction\al {\mCh@set@variable\angle{135}}{}%
+  \mCh@ifeq@variable\direction\l  {\mCh@set@variable\angle{180}}{}%
+  \mCh@ifeq@variable\direction\bl {\mCh@set@variable\angle{225}}{}%
+  \mCh@ifeq@variable\direction\b  {\mCh@set@variable\angle{270}}{}%
+  \mCh@ifeq@variable\direction\br {\mCh@set@variable\angle{315}}{}%
+  \mCh@ifempty@variable\angle{%
+    \pgfmathparse{\mCh@direction <0 ? int(\mCh@direction+360) : int(\mCh@direction) }%
+    \mCh@xset@variable\angle{\pgfmathresult}%
+  }{}%
+}
+% --------------------------------------------------------------------------
+% PFEILE
+% \arrow[<pos>,<type>,<length factor>,<name>,both,<tikz>]{<above>}{<below>}
+% Pfeiltypen:
+\mCh@new@variable\arrow@type@def
+\mCh@new@variable\arrow@type@eqv
+\mCh@new@variable\arrow@type@back
+\mCh@new@variable\arrow@type@eq
+\mCh@new@variable\arrow@type@eqq
+\mCh@new@variable\arrow@type@eeq
+\mCh@new@variable\arrow@type@not
+\mCh@new@variable\arrow@type@pm
+
+\mCh@set@variable\arrow@type@def{->}
+\mCh@set@variable\arrow@type@eqv{<->}
+\mCh@set@variable\arrow@type@back{<-}
+\mCh@set@variable\arrow@type@eq{<=>}
+\mCh@set@variable\arrow@type@eqq{<=>>}
+\mCh@set@variable\arrow@type@eeq{<<=>}
+\mCh@set@variable\arrow@type@not{-|>}
+\mCh@set@variable\arrow@type@pm{-+>}
+
+% Voreinstellungen
+% Pfeillänge
+\mCh@new@variable\arrow@length@def
+\mCh@new@variable\arrow@length
+\mCh@new@variable\arrow@factor
+
+\mCh@set@variable\arrow@length@def{4em}
+\let\mCh@arrow@length\mCh@arrow@length@def
+\mCh@set@variable\arrow@factor{1}
+
+\newrobustcmd\setarrowlength[1]{%
+  \ifblank{#1}
+    {\mCh@let@variable\arrow@length\arrow@length@def}
+    {\mCh@set@variable\arrow@length{#1}}}
+
+% Label-Abstand
+\mCh@new@variable\arrow@label@dist@def
+\mCh@new@variable\arrow@label@dist
+
+\mCh@set@variable\arrow@label@dist@def{.2em}
+\mCh@let@variable\arrow@label@dist\arrow@label@dist@def
+
+\newrobustcmd\setarrowlabel[1]{%
+  \ifblank{#1}
+    {\mCh@let@variable\arrow@label@dist\arrow@label@dist@def}
+    {\mCh@set@variable\arrow@label@dist{#1}}}
+
+% Pfeildicke
+\mCh@new@variable\arrow@linethickness@default
+\mCh@new@variable\arrow@linethickness
+
+\mCh@set@variable\arrow@linethickness@default{semithick}
+\mCh@let@variable\arrow@linethickness\arrow@linethickness@default
+
+\newrobustcmd\setarrowline[1]{%
+  \ifblank{#1}
+    {\mCh@let@variable\arrow@linethickness\arrow@linethickness@default}
+    {\mCh@set@variable\arrow@linethickness{#1}}}
+
+% Winkel untersuchen, um Label richtig anzubringen
+\mCh@new@variable\beta
+\mCh@new@variable\arrow@label@anchor@up
+\mCh@new@variable\arrow@label@anchor@down
+\mCh@new@variable\arrow@label@anchor@add
+\mCh@new@variable\arrow@label@anchor@sub
+\newcount\mCh@alpha
+
+\mCh@def\mCh@evaluate@angle#1{
+  \mCh@alpha=#1
+  \pgfmathparse{cos(\mCh@alpha) > 0}
+  \ifnum\pgfmathresult=1
+    \mCh@set@variable\beta{#1}%
+    \mCh@set@variable\arrow@label@anchor@up{south}%
+    \mCh@set@variable\arrow@label@anchor@down{north}%
+    \ifnum\mCh@alpha<180
+      \mCh@set@variable\arrow@label@anchor@add{east}%
+      \mCh@set@variable\arrow@label@anchor@sub{south}%
+    \else
+      \mCh@set@variable\arrow@label@anchor@add{south}%
+      \mCh@set@variable\arrow@label@anchor@sub{west}%
+    \fi
+  \else
+    \pgfmathparse{cos(\mCh@alpha) == 0}%
+    \ifnum\pgfmathresult=1
+      \mCh@set@variable\beta{0}%
+      \ifnum\mCh@alpha=90
+        \mCh@set@variable\arrow@label@anchor@up{east}%
+        \mCh@set@variable\arrow@label@anchor@down{west}%
+        \mCh@set@variable\arrow@label@anchor@add{east}%
+        \mCh@set@variable\arrow@label@anchor@sub{east}%
+      \else
+        \mCh@set@variable\arrow@label@anchor@up{west}%
+        \mCh@set@variable\arrow@label@anchor@down{east}%
+        \mCh@set@variable\arrow@label@anchor@add{west}%
+        \mCh@set@variable\arrow@label@anchor@sub{west}%
+      \fi
+    \else
+      \mCh@set@variable\arrow@label@anchor@up{north}%
+      \mCh@set@variable\arrow@label@anchor@down{south}%
+      \ifnum\mCh@alpha=180
+        \mCh@set@variable\beta{180-#1}%
+        \mCh@set@variable\arrow@label@anchor@add{north}%
+        \mCh@set@variable\arrow@label@anchor@sub{north}%
+      \fi
+      \ifnum\mCh@alpha>180
+        \mCh@set@variable\beta{180+#1}%
+        \mCh@set@variable\arrow@label@anchor@add{west}%
+        \mCh@set@variable\arrow@label@anchor@sub{north}%
+      \fi
+      \ifnum\mCh@alpha<180
+        \mCh@set@variable\beta{180+#1}%
+        \mCh@set@variable\arrow@label@anchor@add{north}%
+        \mCh@set@variable\arrow@label@anchor@sub{east}%
+      \fi
+    \fi
+  \fi
+}
+
+% Maße der Nodes der Pfeilargumente bestimmen, größere später an Pfeil weitergeben
+\mCh@new@variable\arrow@both
+\mCh@set@variable\arrow@both{both}
+
+\newlength{\mCh@height@A}
+\newlength{\mCh@height@B}
+\newlength{\mCh@arrow@label@height}
+\newlength{\mCh@width@A}
+\newlength{\mCh@width@B}
+\newlength{\mCh@arrow@label@width}
+
+\mCh@def\mCh@savenode{%
+  \global\let\mCh@minx=\pgfpositionnodelaterminx
+  \global\let\mCh@maxx=\pgfpositionnodelatermaxx
+  \global\let\mCh@miny=\pgfpositionnodelaterminy
+  \global\let\mCh@maxy=\pgfpositionnodelatermaxy
+}
+
+% der nächste Befehl benötigt pgf v2.10!
+\mCh@def\mCh@largernode#1#2{%
+  \ifdef\pgfpositionnodelater{%
+    \pgfpositionnodelater{\mCh@savenode}%
+    \node{#1};
+    \deflength{\mCh@width@A}{\mCh@maxx-\mCh@minx}%
+    \deflength{\mCh@height@A}{\mCh@maxy-\mCh@miny}%
+    \node{#2};
+    \deflength{\mCh@width@B}{\mCh@maxx-\mCh@minx}%
+    \deflength{\mCh@height@B}{\mCh@maxy-\mCh@miny}%
+    \pgfmathsetlength{\mCh@arrow@label@width}{max(\mCh@width@A,\mCh@width@B)}%
+    \pgfmathsetlength{\mCh@arrow@label@height}{max(\mCh@height@A,\mCh@height@B)}%
+    \global\mCh@arrow@label@width=\mCh@arrow@label@width
+    \global\mCh@arrow@label@height=\mCh@arrow@label@height
+  }{%
+    \mCh@error{%
+      The command \string\pgfpositionnodelater\space is undefined. Make sure,
+      you have installed the latest version of pgf}{}%
+  }%
+}
+
+% Pfeil zeichnen:
+\newrobustcmd\mCh@arrow[3][]{%
+  \ifstrempty{#1}
+    {\mCh@arrow@i}{\mCh@arrow@ii[#1]}
+  {#2}{#3}}
+
+\mCh@def\mCh@arrow@i#1#2{%
+  \node[on chain=going {at=(\tikzchainprevious.0)},
+    minimum size=0,
+    inner sep=3pt,
+    outer sep=0,
+    anchor=180,
+    shift=(0:.5*\mCh@rxn@node@distance)] (@mCh@arrow@start){};
+  \node[on chain=going {at=(\tikzchainprevious.0),
+    shift=($(0:.5*\mCh@arrow@factor*\mCh@arrow@length)$)},
+    minimum size=0,
+    inner sep=3pt,
+    outer sep=0] (@mCh@arrow@end){};
+  \draw[-mCtip,\mCh@arrow@linethickness]
+    let \n1={0}, \n2={180}
+    in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](mCh@arrow@center){}
+      ++($(0:\mCh@arrow@factor*\mCh@arrow@length)$);
+  \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+    rotate=0,
+    anchor=south,
+    inner sep=0]
+    at ($(mCh@arrow@center)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#1};
+  \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+    rotate=0,
+    anchor=north,
+    inner sep=0]
+    at ($(mCh@arrow@center)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#2};
+}
+
+\mCh@new@variable\arrow@plusminus
+\mCh@new@variable\anchor
+\mCh@new@variable\arrow@tikz
+\mCh@new@variable\arrow@type@valid
+\mCh@new@variable\arrow@type
+\mCh@new@variable\arrow@type@actual
+\mCh@new@variable\arrow@name
+
+\mCh@def\mCh@arrow@ii[#1]#2#3{%
+  \mCh@empty@variable\arrow@plusminus
+  \mCh@empty@variable\arrow@type
+  \let\mCh@remainargs\@empty
+  \mCh@splitarg{#1}%
+  \mCh@ifempty@variable\firstarg{% erste Option: Richtung
+    \mCh@set@variable\angle{0}%
+    \mCh@set@variable\beta{0}%
+    \mCh@set@variable\arrow@label@anchor@up{south}%
+    \mCh@set@variable\arrow@label@anchor@down{north}%
+    \mCh@set@variable\arrow@label@anchor@add{south}%
+    \mCh@set@variable\arrow@label@anchor@sub{south}%
+    \mCh@set@variable\anchor{180}%
+    \mCh@empty@variable\referred@node
+  }{%
+    \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+    \mCh@set@variable\anchor{180+\mCh@angle}%
+    \mCh@evaluate@angle{\mCh@angle}%
+  }
+  \mCh@ifempty@variable\referred@node{%
+    \mCh@set@variable\referred@node{\tikzchainprevious}%
+  }{}%
+  \mCh@ifempty@variable\secondarg{}{% zweite Option: Typ
+    \mCh@set@variable\arrow@type{true}
+    \mCh@let@variable\arrow@type@actual\secondarg
+  }%
+  \let\mCh@remainargs\@empty%
+  \expandafter\mCh@splitarg\expandafter{\mCh@thirdarg}%
+  \mCh@ifempty@variable\firstarg{% dritte Option: Längenfaktor
+    \mCh@set@variable\arrow@factor{1}%
+  }{%
+    \mCh@xset@variable\arrow@factor{\mCh@firstarg}%
+  }%
+  \mCh@ifempty@variable\secondarg{% vierte Option: Name
+    \mCh@set@variable\arrow@name{mCh@arrow@center}%
+  }{%
+    \mCh@xset@variable\arrow@name{\mCh@secondarg}%
+  }%
+  \let\mCh@remainargs\@empty%
+  \expandafter\mCh@splitarg\expandafter{\mCh@thirdarg}%
+  \mCh@ifeq@variable\arrow@both\firstarg% fünfte Option: both
+    {{\mCh@largernode{#2}{#3}}}%
+    {%
+      \deflength{\mCh@arrow@label@width}{0pt}%
+      \deflength{\mCh@arrow@label@height}{0pt}%
+    }%
+  \mCh@ifempty@variable\secondarg{% sechste Option: tikz
+    \mCh@empty@variable\arrow@tikz
+  }{%
+    \mCh@xset@variable\arrow@tikz{\mCh@secondarg,\mCh@thirdarg}%
+  }%
+  \node[on chain=going {at=(\mCh@referred@node.\mCh@angle)},
+    minimum size=0,
+    inner sep=3pt,
+    outer sep=0,
+    anchor=\mCh@anchor,
+    shift=(\mCh@angle:.5*\mCh@rxn@node@distance)] (@mCh@arrow@start){};
+  \node[on chain=going {at=(\tikzchainprevious.\mCh@angle),
+    shift=($(\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$)},
+    minimum size=0,
+    inner sep=3pt,
+    outer sep=0] (@mCh@arrow@end){};
+  \mCh@ifeq@variable\arrow@type\true{%
+    \mCh@let@variable\arrow@type@valid\false
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@eq{% <=>
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        -mChtip,
+        \mCh@arrow@linethickness]
+        let \n1={20+\mCh@angle}, \n2={160+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](mCh@arrow@center@up){}
+          ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        mChtip-,
+        \mCh@arrow@linethickness]
+        let \n1={-20+\mCh@angle}, \n2={200+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](mCh@arrow@center@down){}
+          ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \draw[draw=none]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+          ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@up)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node[\expandafter\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@down)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@eqq{% <=>>
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        -mChtip,
+        \mCh@arrow@linethickness]
+        let \n1={20+\mCh@angle}, \n2={160+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](mCh@arrow@center@up){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        mChtip-,
+        \mCh@arrow@linethickness]
+        let \n1={-20+\mCh@angle}
+        in ($(@mCh@arrow@start.\n1)+(\mCh@angle:.25*\mCh@arrow@factor*\mCh@arrow@length)$)
+          --node[pos=.5,inner sep=0](mCh@arrow@center@down){}
+          ++($(\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$);
+      \draw[draw=none] let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@up)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@down)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@eeq{% <<=>
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        -mChtip,
+        \mCh@arrow@linethickness]
+        let \n1={20+\mCh@angle}, \n2={160+\mCh@angle}
+        in ($(@mCh@arrow@start.\n1)+(\mCh@angle:.25*\mCh@arrow@factor*\mCh@arrow@length)$)
+        --node[pos=.5,inner sep=0](mCh@arrow@center@up){}
+        ++($(\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        mChtip-,
+        \mCh@arrow@linethickness]
+        let \n1={-20+\mCh@angle}, \n2={200+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](mCh@arrow@center@down){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \draw[draw=none]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@up)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(mCh@arrow@center@down)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@def{% ->
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        -mCtip,
+        \mCh@arrow@linethickness,
+        \mCh@arrow@tikz]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height]
+        at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height]
+        at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@eqv{% <->
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        mCtip-mCtip,
+        \mCh@arrow@linethickness]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,inner sep=0]
+        at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,inner sep=0]
+        at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@back{% <-
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        mCtip-,
+        \mCh@arrow@linethickness]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0] at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0]
+        at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@not{% -|>
+      \mCh@let@variable\arrow@type@valid\true
+      \expandafter\draw\expandafter[\mCh@arrow@tikz,
+        -mCtip,
+        \mCh@arrow@linethickness]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+      \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@up,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,
+        inner sep=0] at ($(\mCh@arrow@name)!.8em!90:(@mCh@arrow@end)$){#2};
+      \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+        rotate=\mCh@beta,
+        anchor=\mCh@arrow@label@anchor@down,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height,inner sep=0]
+        at ($(\mCh@arrow@name)!.8em!-90:(@mCh@arrow@end)$){#3};
+      \draw ($(mCh@arrow@center)!.6em!-110:(@mCh@arrow@end)+(\mCh@angle:.1em)$)
+        --($(mCh@arrow@center)!.6em!70:(@mCh@arrow@end)+(\mCh@angle:.1em)$);
+      \draw ($(mCh@arrow@center)!.6em!-110:(@mCh@arrow@end)+(180+\mCh@angle:.1em)$)
+        --($(mCh@arrow@center)!.6em!70:(@mCh@arrow@end)+(180+\mCh@angle:.1em)$);
+    }{}%
+    \mCh@ifeq@variable\arrow@type@actual\arrow@type@pm{% -+>
+      \mCh@let@variable\arrow@type@valid\true
+      \mCh@let@variable\arrow@plusminus\true
+      \draw[-mCtip,\mCh@arrow@linethickness]
+        let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+        in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+        ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+    }{}%
+    \mCh@ifeq@variable\arrow@type@valid\false
+      {\mCh@error{Unknown arrow type `\mCh@arrow@type@actual'}{}}{}%
+  }{% default: ->
+    \expandafter\draw\expandafter[\mCh@arrow@tikz,
+      -mCtip,
+      \mCh@arrow@linethickness]
+      let \n1={\mCh@angle}, \n2={180+\mCh@angle}
+      in (@mCh@arrow@start.\n1) --node[pos=.5,inner sep=0](\mCh@arrow@name){}
+      ++($(\mCh@angle:\mCh@arrow@factor*\mCh@arrow@length)$);
+    \expandafter\node\expandafter[\mCh@arrow@uplabel@visible,
+      rotate=\mCh@beta,
+      anchor=\mCh@arrow@label@anchor@up,
+      minimum width=\mCh@arrow@label@width,
+      minimum height=\mCh@arrow@label@height,inner sep=0]
+      at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!90:(@mCh@arrow@end)$){#2};
+    \expandafter\node\expandafter[\mCh@arrow@downlabel@visible,
+      rotate=\mCh@beta,
+      anchor=\mCh@arrow@label@anchor@down,
+      minimum width=\mCh@arrow@label@width,
+      minimum height=\mCh@arrow@label@height,inner sep=0]
+      at ($(\mCh@arrow@name)!\mCh@arrow@label@dist!-90:(@mCh@arrow@end)$){#3};
+  }%
+  \mCh@ifempty@variable\arrow@plusminus{}{%
+    \ifstrempty{#2}{}{%
+      \draw (\mCh@arrow@name.base) edge[bend left]
+        ++(${0.6667}*(146.3+\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$);
+      \node[anchor=\mCh@arrow@label@anchor@add,
+        inner sep=\mCh@arrow@label@dist,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height]
+        at ($(\mCh@arrow@name.base)+{0.6667}*(146.3+\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$) {#2};
+    }%
+    \ifstrempty{#3}{}{%
+      \draw (\mCh@arrow@name.base) edge[bend right,-mCtip]
+        ++(${0.6667}*(33.7+\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$);
+      \node[anchor=\mCh@arrow@label@anchor@sub,
+        inner sep=\mCh@arrow@label@dist,
+        minimum width=\mCh@arrow@label@width,
+        minimum height=\mCh@arrow@label@height]
+        at ($(\mCh@arrow@name.base)+{0.6667}*(33.7+\mCh@angle:.5*\mCh@arrow@factor*\mCh@arrow@length)$) {#3};
+    }%
+  }%
+  \mCh@set@variable\arrow@factor{1}%
+}
+
+% eigene Pfeilspitze ------------------------------------------------------------------ %
+\pgfarrowsdeclare{mCtip}{mCtip}
+  {%
+    \arrowsize=0.2pt
+    \advance\arrowsize by .5\pgflinewidth
+    \pgfarrowsleftextend{-4\arrowsize-.5\pgflinewidth}%
+    \pgfarrowsrightextend{.5\pgflinewidth}%
+  }
+  {%
+    \pgfsetdash{}{0pt}% do not dash
+    \pgfsetroundjoin% fix join
+    \pgfsetroundcap% fix cap
+    \pgfpathmoveto{\pgfpointorigin}%
+    \pgfpathlineto{\pgfpoint{-3pt}{1pt}}%
+    \pgfpathlineto{\pgfpoint{-1.5pt}{0pt}}%
+    \pgfpathlineto{\pgfpoint{-3pt}{-1pt}}%
+    \pgfpathlineto{\pgfpoint{0pt}{0pt}}%
+    \pgfusepathqfillstroke
+  }
+
+\pgfarrowsdeclare{mChtip}{mChtip}
+  {%
+    \arrowsize=0.2pt
+    \advance\arrowsize by .5\pgflinewidth
+    \pgfarrowsleftextend{-4\arrowsize-.5\pgflinewidth}%
+    \pgfarrowsrightextend{.5\pgflinewidth}%
+  }
+  {%
+    \pgfsetdash{}{0pt}% do not dash
+    \pgfsetroundjoin% fix join
+    \pgfsetroundcap% fix cap
+    \pgfpathmoveto{\pgfpoint{0pt}{0pt}}%
+    \pgfpathlineto{\pgfpoint{-3pt}{1pt}}%
+    \pgfpathlineto{\pgfpoint{-1.5pt}{0pt}}%
+    \pgfpathlineto{\pgfpoint{0pt}{0pt}}%
+    \pgfusepathqfillstroke
+  }
+
+% --------------------------------------------------------------------------
+% MERGE
+% \merge[<label>,<pos>,<length>]{<target>}{<start a>}{<start b>}
+\mCh@new@variable\merge@length
+\mCh@new@variable\merge@length@default
+\mCh@new@variable\merge@length@value
+\mCh@new@variable\merge@arg
+\mCh@new@variable\merge@to
+\mCh@new@variable\merge@from@one
+\mCh@new@variable\merge@from@two
+
+\mCh@set@variable\merge@length@default{3em}
+\mCh@let@variable\merge@length@value\merge@length@default
+
+% Basisbefehle
+\mCh@def\mCh@merge@right{%
+  \draw[mCtip-,\mCh@arrow@linethickness]
+    ($(\mCh@merge@to.west)+(-\mCh@rxn@node@distance,0)$)
+    --node[midway,above,yshift=.1em]{\mCh@merge@arg}
+    ++(-\mCh@merge@length,0) node(crossing) {};
+  \draw[\mCh@arrow@linethickness]
+    ($(\mCh@merge@from@one.east)+(\mCh@rxn@node@distance,0)$) -| (crossing.base);
+  \draw[\mCh@arrow@linethickness]
+    ($(\mCh@merge@from@two.east)+(\mCh@rxn@node@distance,0)$) -| (crossing.base);
+}
+
+\mCh@def\mCh@merge@above{%
+  \draw[mCtip-,\mCh@arrow@linethickness]
+    ($(\mCh@merge@to.south)+(0,-\mCh@rxn@node@distance)$)
+    --node[midway,right,xshift=.1em]{\mCh@merge@arg}
+    ++(0,-\mCh@merge@length) node(crossing) {};
+  \draw[\mCh@arrow@linethickness]
+    (crossing.base) -| ($(\mCh@merge@from@one.north)+(0,\mCh@rxn@node@distance)$);
+  \draw[\mCh@arrow@linethickness]
+    (crossing.base) -| ($(\mCh@merge@from@two.north)+(0,\mCh@rxn@node@distance)$);
+}
+
+\mCh@def\mCh@merge@left{%
+  \draw[mCtip-,\mCh@arrow@linethickness]
+    ($(\mCh@merge@to.east)+(\mCh@rxn@node@distance,0)$)
+    --node[midway,above,yshift=.1em]{\mCh@merge@arg}
+    ++(\mCh@merge@length,0) node(crossing) {};
+  \draw[\mCh@arrow@linethickness]
+    ($(\mCh@merge@from@one.west)+(-\mCh@rxn@node@distance,0)$) -| (crossing.base);
+  \draw[\mCh@arrow@linethickness]
+    ($(\mCh@merge@from@two.west)+(-\mCh@rxn@node@distance,0)$) -| (crossing.base);
+}
+
+\mCh@def\mCh@merge@below{%
+  \draw[mCtip-,\mCh@arrow@linethickness]
+    ($(\mCh@merge@to.north)+(0,\mCh@rxn@node@distance)$)
+    --node[midway,right,xshift=.1em]{\mCh@merge@arg}
+    ++(0,\mCh@merge@length) node(crossing) {};
+  \draw[\mCh@arrow@linethickness]
+    (crossing.base) -| ($(\mCh@merge@from@one.south)+(0,-\mCh@rxn@node@distance)$);
+  \draw[\mCh@arrow@linethickness]
+    (crossing.base) -| ($(\mCh@merge@from@two.south)+(0,-\mCh@rxn@node@distance)$);
+}
+
+% eigentlicher Befehl ----------------------------------------------------------------- %
+\newrobustcmd\mCh@merge[4][]{%
+  \ifblank{#1}
+    {\mCh@merge@i}{\mCh@merge@ii[#1]}
+  {#2}{#3}{#4}}
+
+\mCh@def\mCh@merge@i#1#2#3{%
+  \mCh@let@variable\merge@length\merge@length@value
+  \mCh@empty@variable\merge@arg
+  \mCh@set@variable\merge@to{#1}%
+  \mCh@set@variable\merge@from@one{#2}%
+  \mCh@set@variable\merge@from@two{#3}%
+  \mCh@merge@below
+}
+
+\mCh@def\mCh@merge@ii[#1]#2#3#4{%
+  \let\mCh@remainargs\@empty
+  \mCh@splitarg{#1}%
+  \mCh@ifempty@variable\firstarg
+    {\mCh@empty@variable\merge@arg}
+    {\mCh@let@variable\merge@arg\firstarg}%
+  \mCh@ifempty@variable\thirdarg
+    {\mCh@let@variable\merge@length\merge@length@value}
+    {\mCh@set@variable\merge@length{\mCh@thirdarg}}%
+  \mCh@set@variable\merge@to{#2}%
+  \mCh@set@variable\merge@from@one{#3}%
+  \mCh@set@variable\merge@from@two{#4}%
+  \mCh@ifempty@variable\secondarg
+    {\mCh@merge@below}
+    {\csuse{mCh@merge@\mCh@secondarg}}%
+}
+
+\newrobustcmd\setmergelength[1]{%
+  \ifblank{#1}
+    {\mCh@let@variable\merge@length@value\merge@length@default}
+    {\mCh@set@variable\merge@length@value{#1}}}
+
+% --------------------------------------------------------------------------
+% REAKTIONSSCHEMA
+\newlength\mCh@rxn@node@distance@default
+\newlength\mCh@rxn@node@distance
+
+\deflength\mCh@rxn@node@distance@default{1em}
+\deflength\mCh@rxn@node@distance{\mCh@rxn@node@distance@default}
+
+\newrobustcmd\setrcndist[1]{%
+  \ifblank{#1}
+    {\deflength\mCh@rxn@node@distance{\mCh@rxn@node@distance@default}}
+    {\deflength\mCh@rxn@node@distance{#1}}}
+
+% Schema
+% \begin{rxnscheme}[<label>,<placement>,<align>,<scale factor>,<name>]{<caption>}
+\mCh@new@variable\rs@scale
+\mCh@new@variable\rs@currentscale
+
+\mCh@set@variable\rs@scale{1.0}
+\mCh@set@variable\rs@currentscale{\mCh@rs@scale}
+
+\newrobustcmd\setschemename[1]{%
+  \mCh@set@variable\rs@name{#1}}
+
+\mCh@new@variable\rs@caption
+\mCh@new@variable\rs@label
+\mCh@new@variable\rs@currentlabel
+\mCh@new@variable\rs@align
+\mCh@new@variable\rs@right
+\mCh@new@variable\rs@center
+\mCh@new@variable\rs@left
+
+\mCh@let@variable\rs@currentlabel\rs@label
+\mCh@set@variable\rs@align{center}
+\mCh@set@variable\rs@right{right}
+\mCh@set@variable\rs@center{center}
+\mCh@set@variable\rs@left{left}
+
+\newrobustcmd\setschemealign[1]{%
+  \ifblank{#1}
+    {\mCh@set@variable\rs@align{center}}
+    {\mCh@set@variable\rs@align{#1}}}
+
+% Gleitumgebung
+\floatstyle{ruled}
+\newfloat{rxnfloat}{\mCh@rs@currentplacement}{rxnscheme}
+\floatname{rxnfloat}{\mCh@rs@name}% Name ändern
+
+% eigentliche Umgebung:
+\newrobustcmd\mCh@rxnscheme[2][]{%
+  \ifblank{#1}
+    {\mCh@rxnscheme@i}
+    {\mCh@empty@variable\rs@currentlabel\mCh@rxnscheme@ii[#1]}%
+  {#2}}
+
+\mCh@def\mCh@rxnscheme@ii[#1]#2{% [<label>,<placement>,<align>,<scale>,<name>]
+  \let\mCh@remainargs\@empty
+  \mCh@splitarg{#1}%
+  \mCh@ifempty@variable\firstarg% erste Option
+    {\mCh@empty@variable\rs@currentlabel}
+    {\mCh@let@variable\rs@currentlabel\firstarg}%
+  \mCh@ifempty@variable\secondarg% zweite Option
+    {\mCh@let@variable\rs@currentplacement\rs@placement}
+    {\mCh@let@variable\rs@currentplacement\secondarg}%
+  \let\mCh@remainargs\@empty
+  \expandafter\mCh@splitarg\expandafter{\mCh@thirdarg}%
+  \mCh@ifempty@variable\firstarg% dritte Option
+    {\mCh@set@variable\rs@align{center}}
+    {\mCh@let@variable\rs@align\firstarg}%
+  \mCh@ifempty@variable\secondarg% vierte Option
+    {\mCh@set@variable\rs@currentscale{1}}
+    {\mCh@let@variable\rs@currentscale\secondarg}%
+  \mCh@ifempty@variable\thirdarg{}% fünfte Option
+    {\mCh@let@variable\rs@name\thirdarg}%
+  \mCh@rxnscheme@i{#2}%
+}
+
+\mCh@def\mCh@scheme@enable{%
+  \let\arrow\mCh@arrow
+  \let\reactant\mCh@reactant
+  \let\mesomeric\mCh@mesomeric
+  \let\transition\mCh@transition
+  \let\anywhere\mCh@anywhere
+  \let\dummy\mCh@dummy
+  \let\branch\mCh@branch
+  \let\chemand\mCh@chemand
+  \let\merge\mCh@merge
+%   \let\elmove\mCh@elmove
+}
+
+\mCh@def\mCh@scheme@disable{%
+  \let\arrow\relax
+  \let\reactant\relax
+  \let\mesomeric\relax
+  \let\transition\relax
+  \let\anywhere\relax
+  \let\dummy\relax
+  \let\branch\relax
+  \let\chemand\relax
+  \let\merge\relax
+%   \let\elmove\relax
+}
+
+\mCh@def\mCh@rxnscheme@i#1{%
+  \mCh@scheme@enable
+  \mCh@set@variable\rs@caption{#1}%
+  \rxnfloat
+  \mCh@ifeq@variable\rs@align\rs@center{\centering}{}%
+  \mCh@ifeq@variable\rs@align\rs@left{\raggedright}{}%
+  \mCh@ifeq@variable\rs@align\rs@right{\raggedleft}{}%
+  \mCh@atomsize\mCh@bondlength\mCh@bondshape
+  \tikzpicture[
+    every picture/.style={scale=\mCh@rs@currentscale},
+    start chain,
+    node distance=\mCh@rxn@node@distance,
+    inner sep=0pt,
+    outer sep=0pt]
+  \mCh@dummy
+}
+
+\newenvironment{rxnscheme}{\mCh@rxnscheme}{%
+  \endtikzpicture
+  \caption{\mCh@rs@caption}%
+  \mCh@ifempty@variable\rs@currentlabel{}
+     {\label{\mCh@rs@currentlabel}}%
+  \endrxnfloat
+  \mCh@scheme@disable
+}
+
+% ----------------------------------------------------------------------------
+% einfache Reaktion
+% \begin{rxn}[<align>,<scalefactor>]
+\mCh@new@variable\reaction@scale
+\mCh@new@variable\reaction@align
+
+\mCh@set@variable\reaction@scale{1.0}
+\mCh@set@variable\reaction@align{center}
+
+\newrobustcmd\setrxnalign[1]{%
+  \ifblank{#1}
+    {\mCh@set@variable\reaction@align{center}}
+    {\mCh@set@variable\reaction@align{#1}}}
+
+\mCh@new@variable\reaction@right
+\mCh@new@variable\reaction@center
+\mCh@new@variable\reaction@left
+
+\mCh@set@variable\reaction@right{right}
+\mCh@set@variable\reaction@center{center}
+\mCh@set@variable\reaction@left{left}
+
+\newrobustcmd\mCh@rxn[1][]{%
+  \ifblank{#1}
+    {\mCh@rxn@i}{\mCh@rxn@ii[#1]}}
+
+\mCh@def\mCh@rxn@ii[#1]{%
+  \let\mCh@remainargs\@empty
+  \mCh@splitarg{#1}%
+  \mCh@ifempty@variable\firstarg
+    {\mCh@let@variable\reaction@align\reaction@center}
+    {\mCh@let@variable\reaction@align\firstarg}%
+  \mCh@ifempty@variable\secondarg
+    {\mCh@set@variable\reaction@scale{1}}
+    {\mCh@let@variable\reaction@scale\secondarg}%
+  \mCh@rxn@i
+}
+
+\mCh@def\mCh@rxn@i{%
+  \mCh@scheme@enable
+  \hspace*{0pt}%
+  \mCh@ifeq@variable\reaction@align\reaction@center{\center}{}%
+  \mCh@ifeq@variable\reaction@align\reaction@left{\flushleft}{}%
+  \mCh@ifeq@variable\reaction@align\reaction@right{\flushright}{}%
+  \mCh@bondlength\mCh@bondshape\mCh@atomsize
+  \begin{tikzpicture}[
+    every picture/.style={scale=\mCh@reaction@scale},
+    start chain,
+    node distance=\mCh@rxn@node@distance,
+    inner sep=0pt,
+    outer sep=0pt]
+  \mCh@dummy
+}
+
+\newenvironment{rxn}{\mCh@rxn}{%
+  \end{tikzpicture}%
+  \mCh@ifeq@variable\reaction@align\reaction@center{\endcenter}{}%
+  \mCh@ifeq@variable\reaction@align\reaction@left{\endflushleft}{}%
+  \mCh@ifeq@variable\reaction@align\reaction@right{\endflushright}{}%
+  \mCh@scheme@disable
+}
+
+% --------------------------------------------------------------------------
+% REAKTANDEN
+% Standardreaktand
+% \reactant[<pos>,<name>,<tikz>]{<something>}
+\def\mCh@argument@safe{\@makeother\#}
+
+\newrobustcmd\mCh@reactant[1][]{%
+  \begingroup
+    \mCh@argument@safe
+    \ifblank{#1}
+      {\mCh@reactant@i}
+      {\mCh@reactant@ii[#1]}%
+}
+
+\mCh@def\mCh@reactant@i#1{%
+    \expandafter\node\expandafter[%
+      \mCh@reactant@visible,
+      on chain=going {at=(\tikzchainprevious.0)},
+      anchor=180,
+      shift=(0:\mCh@rxn@node@distance)]{#1};
+  \endgroup
+}
+
+\mCh@def\mCh@reactant@ii[#1]#2{%
+    \let\mCh@remainargs\@empty\mCh@splitarg{#1}%
+    \mCh@ifempty@variable\firstarg{% erste Option: <pos>, zweite Option: <name>, dritte Option: <tikz>
+      \mCh@set@variable\angle{0}%
+      \mCh@set@variable\anchor{180}%
+      \mCh@empty@variable\referred@node
+    }{%
+      \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+      \mCh@set@variable\anchor{180+\mCh@angle}%
+    }%
+    \mCh@ifempty@variable\referred@node
+      {\mCh@set@variable\referred@node{\tikzchainprevious}}{}%
+    \expandafter\expandafter\expandafter\node\expandafter\expandafter\expandafter[%
+      \expandafter\mCh@thirdarg\expandafter,%
+      \mCh@reactant@visible,
+      on chain=going {at=(\mCh@referred@node.\mCh@angle)},
+      anchor=\mCh@anchor,shift=(\mCh@angle:\mCh@rxn@node@distance)]
+      (\mCh@secondarg){#2};
+  \endgroup
+}
+
+% Mesomerie
+% \mesomeric[<pos>,<name>,<tikz>]{<something>}
+\newrobustcmd\mCh@mesomeric[1][]{%
+  \begingroup
+    \mCh@argument@safe
+    \ifblank{#1}
+      {\mCh@mesomeric@i}
+      {\mCh@mesomeric@ii[#1]}%
+}
+
+\mCh@def\mCh@mesomeric@i#1{%
+    \node[on chain=going {at=(\tikzchainprevious.0),
+      shift=($(0:\mCh@rxn@node@distance)$)},
+      anchor=180,shift=(0:\mCh@rxn@node@distance),
+      inner sep=1pt,
+      left delimiter={[},
+      right delimiter={]}]
+      {\tikzpicture[start branch]#1\endtikzpicture};
+  \endgroup
+}
+
+\mCh@def\mCh@mesomeric@ii[#1]#2{%
+    \let\mCh@remainargs\@empty
+    \mCh@splitarg{#1}%
+    \mCh@ifempty@variable\firstarg{% erste Option: <pos>, zweite Option: <name>, dritte Option: <tikz>
+      \mCh@set@variable\angle{0}%
+      \mCh@set@variable\anchor{180}%
+      \mCh@empty@variable\referred@node
+    }{%
+      \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+      \mCh@set@variable\anchor{180+\mCh@angle}%
+    }%
+    \mCh@ifempty@variable\referred@node
+      {\mCh@set@variable\referred@node{\tikzchainprevious}}{}%
+    \expandafter\node\expandafter[\mCh@thirdarg,
+      on chain=going {at=(\mCh@referred@node.\mCh@angle)},
+      anchor=\mCh@anchor,
+      shift=(\mCh@angle:\mCh@rxn@node@distance),
+      inner sep=1pt,
+      left delimiter={[},
+      right delimiter={]}]
+      (\mCh@secondarg){\tikzpicture[start branch]#2\endtikzpicture};
+  \endgroup
+}
+
+% Mesomerie-Pfeil
+% \marrow[<pos>]
+\newrobustcmd\marrow[1][]{\arrow[#1,<->,.5]{}{}}
+
+% Anywhere
+% \anywhere{<pos>,<name>,<tikz>}{<something>}
+\mCh@new@variable\anywhere@positioning
+
+\newrobustcmd\mCh@anywhere[1]{%
+  \begingroup
+    \mCh@argument@safe
+    \let\mCh@remainargs\@empty
+    \mCh@splitarg{#1}% erste Option: <pos>, zweite Option: <name>, dritte Option: <tikz>
+    \mCh@ifempty@variable\firstarg{%
+      \mCh@error{\string\anywhere: positioning missing}{}%
+    }{%
+      \expandafter\mCh@if@instr\expandafter{\mCh@firstarg}{=}{%
+        \mCh@xset@variable\anywhere@positioning{\mCh@firstarg}%
+      }{%
+        \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+        \mCh@set@variable\anchor{180+\mCh@angle}%
+        \mCh@ifempty@variable\referred@node{%
+          \mCh@error{You can't use `angle' to position \string\anywhere.
+          You need to use `name.angle'}%
+        }{%
+          \mCh@set@variable\anywhere@positioning{%
+            at=(\mCh@referred@node.\mCh@angle),anchor=\mCh@anchor}%
+        }%
+      }%
+    }%
+    \mCh@anywhere@i
+}
+
+\mCh@def\mCh@anywhere@i#1{%
+    \expandafter\expandafter\expandafter\node\expandafter\expandafter\expandafter[%
+      \expandafter\mCh@thirdarg\expandafter,%
+      \mCh@anywhere@positioning](\mCh@secondarg){#1};
+  \endgroup
+}
+
+% Dummy
+% \dummy[<name>]
+\newrobustcmd\mCh@dummy[1][]{%
+  \ifblank{#1}
+    {\draw node[on chain,xshift=-\mCh@rxn@node@distance]{};}
+    {\draw node[on chain,xshift=-\mCh@rxn@node@distance](#1){};}}
+
+% Uebergangszustand
+% \transition[<pos>,<name>,<tikz>]{<something>}
+\mCh@new@variable\transition@name
+
+\newrobustcmd\mCh@transition[1][]{%
+  \begingroup
+    \mCh@argument@safe
+    \ifblank{#1}
+      {\mCh@transition@i}
+      {\mCh@transition@ii[#1]}%
+}
+
+\mCh@def\mCh@transition@i#1{%
+    \expandafter\node\expandafter[\mCh@reactant@visible,
+      on chain=going {at=(\tikzchainprevious.0)},
+      anchor=180,
+      shift=(0:\mCh@rxn@node@distance),
+      anchor=180,
+      inner sep=3pt,
+      left delimiter={[},
+      right delimiter={]}]
+      (mCh@transition@name){#1};
+    \node at ($(mCh@transition@name.north east)+(.7em,0)$)
+      {$\transitionstatesymbol$};
+  \endgroup
+}
+
+\mCh@def\mCh@transition@ii[#1]#2{%
+    \let\mCh@remainargs\@empty
+    \mCh@splitarg{#1}%
+    \mCh@ifempty@variable\firstarg{% erste Option: <pos>
+      \mCh@set@variable\angle{0}%
+      \mCh@set@variable\anchor{180}%
+      \mCh@empty@variable\referred@node
+    }{%
+      \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+      \mCh@set@variable\anchor{180+\mCh@angle}%
+    }%
+    \mCh@ifempty@variable\secondarg% zweite Option: <name>, dritte Option: <tikz>
+      {\mCh@set@variable\transition@name{mCh@transition@name}}
+      {\mCh@let@variable\transition@name\secondarg}%
+    \mCh@ifempty@variable\referred@node
+      {\mCh@set@variable\referred@node{\tikzchainprevious}}{}%
+    \expandafter\expandafter\expandafter\node\expandafter\expandafter\expandafter[%
+      \mCh@reactant@visible\expandafter,%
+      \mCh@thirdarg,
+      on chain=going {at=(\mCh@referred@node.\mCh@angle)},
+      anchor=\mCh@anchor,
+      shift=(\mCh@angle:\mCh@rxn@node@distance),
+      inner sep=3pt,
+      left delimiter={[},
+      right delimiter={]}]
+      (\mCh@transition@name){#2};
+    \node at ($(\mCh@transition@name.north east)+(.7em,0)$)
+      {$\transitionstatesymbol$};
+  \endgroup
+}
+
+% Abzweigung
+% \branch[<pos>,<name>,<tikz>]{<formulae>}
+% <pos>: default: on chain=going "right" (0°)
+%        on chain=going <somewhere>
+%        <somewhere>=of <name>
+%        <angle> (sitzt auf der Kette)
+%        <name>.<angle> (sitzt nicht auf der Kette)
+\mCh@new@variable\branch@positioning
+
+\newrobustcmd\mCh@branch[1][]{%
+  \begingroup
+    \mCh@argument@safe
+    \ifblank{#1}
+      {\mCh@branch@i}
+      {\mCh@branch@ii[#1]}%
+}
+
+\mCh@def\mCh@branch@i{%
+  \expandafter\mCh@set@variable\expandafter\branch@positioning\expandafter{\mCh@branch@visible,
+    on chain=going {at=(\tikzchainprevious.0)},
+    anchor=180,
+    shift=(0:\mCh@rxn@node@distance)}%
+  \mCh@empty@variable\secondarg
+  \mCh@empty@variable\thirdarg
+  \mCh@branch@iii}
+
+\mCh@def\mCh@branch@ii[#1]{%
+  \let\mCh@remainargs\@empty
+  \mCh@splitarg{#1}% erste Option: <pos>, zweite Option: <name>, dritte Option: <tikz>
+  \mCh@ifempty@variable\firstarg{%
+    \expandafter\mCh@set@variable\expandafter\branch@positioning\expandafter{\mCh@branch@visible,
+      on chain=going {at=(\tikzchainprevious.0)},
+      anchor=180,
+      shift=(0:\mCh@rxn@node@distance)}%
+  }{%
+    \expandafter\mCh@if@instr\expandafter{\mCh@firstarg}{=}{%
+      \mCh@xset@variable\branch@positioning{\mCh@branch@visible,\mCh@firstarg}%
+    }{%
+      \expandafter\mCh@analyze@angle\expandafter{\mCh@firstarg}%
+      \mCh@set@variable\anchor{180+\mCh@angle}%
+      \mCh@ifempty@variable\referred@node{%
+        \expandafter\mCh@set@variable\expandafter\branch@positioning\expandafter{\mCh@branch@visible,
+          on chain=going {at=(\tikzchainprevious.\mCh@angle)},
+          anchor=\mCh@anchor,
+          shift=(\mCh@angle:\mCh@rxn@node@distance)}%
+      }{%
+        \expandafter\mCh@set@variable\expandafter\branch@positioning\expandafter{\mCh@branch@visible,
+          at=(\mCh@referred@node.\mCh@angle),
+          anchor=\mCh@anchor,
+          shift=(\mCh@angle:\mCh@rxn@node@distance)}%
+      }%
+    }%
+  }%
+  \mCh@branch@iii}
+
+\mCh@def\mCh@branch@iii#1{%
+    \expandafter\expandafter\expandafter\node\expandafter\expandafter\expandafter[%
+      \expandafter\mCh@branch@positioning\expandafter,%
+      \mCh@thirdarg]
+      (\mCh@secondarg){\tikzpicture[start branch]#1\endtikzpicture};
+  \endgroup
+}%
+
+
+% --------------------------------------------------------------------------
+% Sonstiges
+% Elektronenverschiebungspfeile
+\mCh@new@variable\elmove@default@tikz
+\mCh@new@variable\elmove@tikz
+
+\tikzset{mCh@elmove/.style={->,red,shorten <=3pt,shorten >=1pt}}
+\mCh@set@variable\elmove@default@tikz{mCh@elmove}
+\mCh@let@variable\elmove@tikz\elmove@default@tikz
+
+\newrobustcmd\elmove[5][]{%
+  \chemmove{
+    \expandafter\draw\expandafter[\mCh@elmove@tikz,#1]
+    (#2).. controls +(#3) and +(#5)..(#4);
+  }}
+
+\newrobustcmd\setelmove[1]{%
+  \ifblank{#1}
+    {\mCh@let@variable\elmove@tikz\elmove@default@tikz}
+    {\mCh@set@variable\elmove@tikz{#1}}}
+
+% Plus
+\newrobustcmd\mCh@chemand[1][]{%
+  \ifblank{#1}
+    {\reactant{\chemsign[0pt]{+}}}
+    {\reactant[#1]{\chemsign[0pt]{+}}}}
+
+% --------------------------------------------------------------------------
+% Setup myChemistry
+% Bindungslänge
+\mCh@new@variable\bondlength@default
+\mCh@new@variable\bondlength
+
+\mCh@set@variable\bondlength@default{1.8em}
+\mCh@set@variable\bondlength{\setatomsep{\mCh@bondlength@default}}
+
+\newrobustcmd\setbondlength[1]{%
+ \ifblank{#1}
+   {\mCh@set@variable\bondlength{\setatomsep{\mCh@bondlength@default}}}
+   {\mCh@set@variable\bondlength{\setatomsep{#1}}}}
+
+% Keilbindungen
+\mCh@new@variable\bondshape@one
+\mCh@new@variable\bondshape@two
+\mCh@new@variable\bondshape@three
+
+\mCh@set@variable\bondshape@one{3pt}
+\mCh@set@variable\bondshape@two{.5pt}
+\mCh@set@variable\bondshape@three{1pt}
+
+\newrobustcmd\setbondshape[3]{%
+ \ifblank{#1}
+   {\mCh@set@variable\bondshape@one{3pt}}
+   {\mCh@set@variable\bondshape@one{#1}}%
+ \ifblank{#2}
+   {\mCh@set@variable\bondshape@two{.5pt}}
+   {\mCh@set@variable\bondshape@two{#2}}%
+ \ifblank{#3}
+   {\mCh@set@variable\bondshape@three{1pt}}
+   {\mCh@set@variable\bondshape@three{#3}}%
+}
+
+\mCh@new@variable\bondshape
+\mCh@set@variable\bondshape{%
+  \setcrambond{\mCh@bondshape@one}{\mCh@bondshape@two}{\mCh@bondshape@three}}
+
+% Atomgröße
+\mCh@new@variable\atomsize@default
+\mCh@new@variable\atomsize
+
+\mCh@set@variable\atomsize@default{\small}
+\mCh@let@variable\atomsize\atomsize@default
+
+\newrobustcmd\setatomsize[1]{%
+ \ifblank{#1}
+   {\mCh@let@variable\atomsize\atomsize@default}
+   {\mCh@set@variable\atomsize{#1}}}
+
+% allg. Setup
+\newrobustcmd\mCsetup[1]{\setkeys{mCh@setup}{#1}}
+
+\define@key{mCh@setup}{arrowlabel}[\mCh@arrow@label@dist@def]{%
+  \setarrowlabel{#1}}
+\define@key{mCh@setup}{arrowlength}[\mCh@arrow@length@def]{%
+  \setarrowlength{#1}}
+\define@key{mCh@setup}{arrowline}[\mCh@arrow@linethickness@default]{%
+  \setarrowline{#1}}
+\define@key{mCh@setup}{atomsize}[\mCh@atomsize@default]{%
+  \setatomsize{#1}}
+\define@key{mCh@setup}{bondlength}[\mCh@bondlength@default]{%
+  \setbondlength{#1}}
+\define@key{mCh@setup}{rcndist}[\mCh@rxn@node@distance@default]{%
+  \setrcndist{#1}}
+\define@key{mCh@setup}{rxnalign}[center]{%
+  \setrxnalign{#1}}
+\define@key{mCh@setup}{schemealign}[center]{%
+  \setschemealign{#1}}
+\define@key{mCh@setup}{align}[center]{%
+  \setrxnalign{#1}
+  \setschemealign{#1}}
+\define@key{mCh@setup}{mergelength}[\mCh@merge@length@default]{%
+  \setmergelength{#1}}
+\define@key{mCh@setup}{elmove}[\mCh@elmove@default@tikz]{%
+  \setelmove{#1}}
+\define@key{mCh@setup}{reset}[]{%
+  \setarrowlabel{}%
+  \setarrowlength{}%
+  \setarrowline{}%
+  \setmergelength{}%
+  \setatomsize{}%
+  \setbondlength{}%
+  \setbondshape{}{}{}%
+  \setrcndist{}%
+  \setrxnalign{}%
+  \setschemealign{}%
+  \setelmove{}%
+}
+
+% --------------------------------------------------------------------------
+% NODES SICHTBAR/UNSICHTBAR MACHEN
+\mCh@new@variable\reactant@visible
+\mCh@new@variable\arrow@uplabel@visible
+\mCh@new@variable\arrow@downlabel@visible
+\mCh@new@variable\branch@visible
+
+\mCh@empty@variable\reactant@visible
+\mCh@empty@variable\arrow@uplabel@visible
+\mCh@empty@variable\arrow@downlabel@visible
+\mCh@empty@variable\branch@visible
+
+\newrobustcmd\makevisible{%
+  \ifmCh@draft
+    \mCh@set@variable\reactant@visible{draw=red!60,solid}%
+    \mCh@set@variable\arrow@uplabel@visible{draw=green!60,solid}%
+    \mCh@set@variable\arrow@downlabel@visible{draw=blue!60,solid}%
+    \mCh@set@variable\branch@visible{draw=cyan,solid}%
+  \fi
+}
+
+\newrobustcmd\makeinvisible{%
+  \mCh@empty@variable\reactant@visible
+  \mCh@empty@variable\arrow@uplabel@visible
+  \mCh@empty@variable\arrow@downlabel@visible
+  \mCh@empty@variable\branch@visible
+}
+
+\endinput
+
+% ----------------------------------------------------------------------------
+HISTORY:
+2011/02/24 version 1.0   - first release to CTAN
+2011/03/01 version 1.1   - package option `english' added
+                         - package key `placement' added
+                         - rxnscheme key `placement' added
+                         - package key `shade=boolean' changed into package
+                           option `shade'
+                         - package option `nochemexec' added, will prevent mC
+                           from loading chemexec
+2011/03/20 version 1.2   - license changed into LPPL 1.3 or later
+                         - package option `nocompounds' added, will prevent mC
+                           from loading chemcompounds
+                         - package option `chemstyle' added, will load chemstyle
+                         - package option `nomhchem' added, will prevent mC from
+                           loading mhchem if chemexec isn't loaded either
+                         - package option `nopackages' added, will prevent mC
+                           from loading any chemistry package except chemfig
+                         - some small issues resolved
+                         - bug in arrow type <=> resolved
+                         - arrow argument placement rewritten; two new keys for
+                           arrow: `aboveshift' and `belowshift' (causing new
+                           problems with alignment, though)
+                         - wrong arrow alignment (due to last change) mainly
+                           resolved (NEEDS pgf v2.10!)
+                           => solved wrong branch alignment as well
+                         - `inner sep' set to 0, arrow, transition & mesomeric
+                           adjusted
+                         - bug in arrow type -|> resolved
+                         - commands \makevisible / \makeinvisible added
+                         - arrow key `both' added
+                         - rxn has now keys instead of an option
+                         - commands \setrcndist, \setrxnalign, \setschemealign
+                           added
+                         - rxn-, rxnscheme-key align added
+2011/03/26 version 1.2.1 - rewritten commands, so they accept second argument
+                           without first:
+                           \reactand, \mesomeric, \transition, \branch,
+                           \makevisible, \makeinvisible
+2011/03/28 version 1.2.2 - bugfix with transition
+                         - atomsize, arrowlength, bondlength and bondshape
+                           renamed into set<name> and code slightly rewritten
+                         - \mCsetup added
+2011/04/01 version 1.2.3 - bug in \branch resolved
+                         - \chemand added
+2011/04/02 version 1.2.4 - bugs in \makevisible, \makeinvisible resolved
+                         - input bondwidth.tex if ChemFig v0.4
+2011/04/04 version 1.3   - commands \reactand, \mesomeric, \branch, \transition,
+                           \chemand (\makeinvisible,  \makeinvisible) rewritten:
+                           more flexible with opt. arguments
+2011/04/15 version 1.4   - minor bugfixes
+                         - \merge-command rewritten: it now accepts an arrow
+                           label and the length is adjustable
+                         - \dummy mostly obsolete
+                         - bugfix with aligning rxn & rxnscheme
+                         - synonym to \reactand=\reactant added
+                         - rxn & rxnscheme rewritten
+                         - commands \reactant, \mesomeric, \branch & \transition
+                           modified: argument is set with \mCh@argument@safe{#1},
+                           so the chemfig catcode regime is working properly
+                           before () (else possible problem with triple bond ~)
+                         - syntax of \arrow changed so it fits to the syntax of
+                           all the other commands
+                         - command \anywhere added
+                         - own arrow tips defined
+                         - command \setarrowline added
+                         - new arrow type -+> added
+2011/04/23 version 1.5   - major parts of the code rewritten -- the whole
+                           positioning part now is different and way more flexible:
+                           arbitrary angles can be used for positioning, referencing
+                           an object is easier, arrows can be modified using <tikz>,
+                           command \anywhere now has similar syntax
+                         - arrow types <=>> and <<=> added
+                         - arrow type -+> modified: more flexible
+                         - bugfixes in error-handling
+2011/04/27 version 1.5.1 - removed bondwidth.tex
+                         - \arrow, \reactant, \mesomeric, \transition, \anywhere,
+                           \dummy, \branch, and \chemand only defined inside scheme
+                           environments
+2012/07/27 version 1.99  - conflict with `pdfpages' resolved, LaTeXified various
+                           parts in order to minimize conflicts with other
+                           packages; \merge is also only defined inside the scheme
+                           environments
+2012/09/20 version 1.99a - small adjustments to \elmove
+2012/12/19 version 1.99b - changed catcode regime (# is read with catcode 12)
+                           so that chemfig's bond offset works
+                           
+% ----------------------------------------------------------------------------
\ No newline at end of file
diff --git a/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.pdf b/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.pdf
new file mode 100644
index 0000000000..daffa005e0
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.pdf
diff --git a/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.tex b/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.tex
new file mode 100644
index 0000000000..269b8fecbf
--- /dev/null
+++ b/obsolete/macros/latex/contrib/mychemistry/mychemistry_en.tex
@@ -0,0 +1,1724 @@
+% arara: pdflatex
+% arara: pdflatex
+% arara: makeindex: { sort: on, style: mychemistry_en.ist }
+% arara: pdflatex
+% --------------------------------------------------------------------------
+% the MYCHEMISTRY package
+%
+%   create reaction schemes with LaTeX and chemfig
+%
+% --------------------------------------------------------------------------
+% Clemens Niederberger
+% Web:    https://www.bitbucket.org/cgnieder/mychemistry
+% E-Mail: contact@mychemistry.eu
+% --------------------------------------------------------------------------
+% If you have any ideas, questions, suggestions or bugs to report, please
+% feel free to contact me.
+% --------------------------------------------------------------------------
+% Copyright 2011--2012 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.
+%
+% This work consists of the files modiagram.sty, modiagram_en.tex,
+% README and the derived file modiagram_en.pdf.
+% --------------------------------------------------------------------------
+% \errorcontextlines=999
+\documentclass[toc=index,DIV10]{cnpkgdoc}
+\docsetup{
+  pkg = [draft]mychemistry,
+  subtitle = Create Reaction Schemes with \LaTeXe\ and Chemfig ,
+  code-box     = {
+    skipbelow        = .5\baselineskip plus .5ex minus .5ex ,
+    skipabove        = .5\baselineskip plus .5ex minus .5ex ,
+    roundcorner      = 3pt ,
+    innerleftmargin  = 1.5em ,
+    innerrightmargin = 1.5em
+  }
+}
+
+\usepackage{chemnum}
+\usepackage{fnpct}
+\usepackage{booktabs}
+\usepackage{siunitx}
+
+\chemsetup[chemformula]{format=\libertineLF}
+
+\addcmds{
+  @addtoreset,
+  anywhere,
+  arrow,
+  branch,
+  celsius,
+  ch,
+  chemabove,
+  chemand,
+  chembelow,
+  chemfig,
+  chemname,
+  cmpd,
+  colorlet,
+  command,
+  draw,
+  elmove,
+  floatstyle,
+  fpch,
+  fplus,
+  fscrm,
+  fscrp,
+  Hpl,
+  iupac,
+  lewis,
+  Lewis,
+  listof,
+  makeinvisible,
+  makevisible,
+  marrow,
+  mch,
+  mCsetup,
+  mech,
+  mesomeric,
+  N,
+  node,
+  para,
+  pch,
+  phantom,
+  reactant,
+  restylefloat,
+  setarrowlabel,
+  setarrowlength,
+  setarrowline,
+  setatomsep,
+  setatomsize,
+  setbondlength,
+  setbondshape,
+  setcrambond,
+  setmergelength,
+  setrcndist,
+  setrxnalign,
+  setschemealign,
+  setschemename,
+  SI,
+  text,
+  therxnscheme,
+  tikzset,
+  trans,
+  transition
+}
+
+\usepackage{makeidx}
+\usepackage{filecontents}
+\begin{filecontents*}{\jobname.ist}
+ heading_prefix "{\\bfseries "
+ heading_suffix "\\hfil}\\nopagebreak\n"
+ headings_flag  1
+ delim_0 "\\dotfill "
+ delim_1 "\\dotfill "
+ delim_2 "\\dotfill "
+ delim_r "\\nohyperpage{\\textendash}"
+ suffix_2p "\\nohyperpage{\\,f.}"
+ suffix_3p "\\nohyperpage{\\,ff.}"
+\end{filecontents*}
+
+\makeindex
+
+\begin{document}
+\section{Licence and Requirements}\label{ssec:voraussetzungen}
+Permission is granted to copy, distribute and/or modify this software under the
+terms of the LaTeX Project Public License, version 1.3 or later
+(\url{http://www.latex-project.org/lppl.txt}). This package has the status
+``maintained.''
+
+\mychemistry needs and loads the packages \paket{etoolbox}, \paket{float},
+\paket{xkeyval}, \paket{chemmacros} and \paket{chemfig}. It also loads the 
+TikZ-libraries \code{arrows}, \code{positioning}, \code{decorations.pathmorphing},
+\code{shapes}, \code{calc}, \code{matrix}, \code{chains}, \code{scopes} and
+\code{intersections}.
+
+\mychemistry also loads \paket*{translations}\footnote{Part of the
+\paket*{exsheets} package} for proper language support.
+
+\section{Changes}
+With v1.99 (=v2.0beta) package dependencies have changed so that \mychemistry
+loads noticably less packages than before. Most important for you: it does \emph{not}
+load \paket{mhchem} any more. This documentation uses \paket{chemmacros} instead
+which is loaded by \mychemistry.
+
+There are now considerably less package options as most of them are not needed
+any more.
+
+\mychemistry now provides proper language support, \eg, when used together with
+\paket{babel}.
+
+New is the command \cmd{setelmove}. The command \cmd{makevisible} now only has
+an effect if the new option \key{draft} is used.
+
+\section{Background}
+\mychemistry provides two environments within which the mechanisms are created.
+Both environments basically are \code{tikzpicture} environments. When this package
+first was written \paket{chemfig} lacked the possibility of creating reaction
+schemes itself. This was the motivation for me to get started on \mychemistry
+which then rapidly grew and until now has its users.
+
+The background has changed in August 2011, though. Then \paket{chemfig} v1.0 was
+published and now provides simple but powerful macros to create reactions schemes.
+They don't seem to to be used very often but I am advertising as much as I can.
+Anyway, since then \mychemistry can be considered obsolete and is not actively
+developed any more. The current release 1.99 (= 2.0beta) was due to an
+incompatibilty with \paket{pdfpages} and a complete robustification of various
+parts of the code.
+
+\emph{Other than bug fixes this package will very likely \emph{not} be updated
+any more}!
+
+\section{Package options}\label{sec:paketoptionen}
+\mychemistry has a few package options.
+\begin{beschreibung}
+  \option{strict} With this option all warning messages are turned into error
+    messages.
+  \option{draft} This option is an alias to \key{strict}. Additionally it enables
+    the \cmd{makevisible} command.
+  \option{final} This option is the opposite to \key{draft}, \ie, most error
+    messages will be issued as warnings. It also disables the \cmd{makevisible}
+    command.
+  \option{placement}{<value>} Changes the default floating behaviour of \env{rxnscheme},
+    see section~\ref{ssec:rxnscheme}.
+\end{beschreibung}
+
+\section{Usage}
+\subsection{Basic Principle}
+Within the \code{tikzpicture} reactants and arrows are placed as nodes on a
+\code{chain}\footnote{Provided by the tikzlibrary `chains'}.
+
+\begin{beispiel}
+ \begin{tikzpicture}[start chain]
+ \node [on chain] {A};
+ \node [on chain] {B};
+ \node [on chain] {C};
+ \end{tikzpicture}
+\end{beispiel}
+This way there are several possibilities to place the nodes relative to the others.
+\begin{beispiel}
+ \begin{tikzpicture}[start chain=going right,node distance=5mm]
+ \node [draw,on chain] {Hello};
+ \node [draw,on chain] {World};
+ \node [draw,continue chain=going below,on chain] {,};
+ \node [draw,on chain] {this};
+ \node [draw,on chain] {is};
+ \end{tikzpicture}
+\end{beispiel}
+
+Above all \mychemistry uses the possibility of creating branches to the chain.
+\begin{beispiel}
+ \begin{tikzpicture}[start chain=going right,node distance=5mm]
+  \node [draw,on chain] {A};
+  \node [draw,on chain] {B};
+ { [start branch]
+  \node [on chain=going below] {1};
+  \node [on chain=going below] {2};
+ }
+ { [start branch]
+  \node [on chain=going above] {$\alpha$};
+  \node [on chain=going above] {$\beta$};
+ }
+  \node [draw,on chain] {C};
+ \end{tikzpicture}
+\end{beispiel}
+You don't have to understand that mechanism in detail but you should remember the
+placement commands in the last example, because \mychemistry uses them in the same
+way.
+
+In some of the examples in this documentation the nodes are boxed with a coloured
+frame (see section~\ref{ssec:makevisible}). This is done so one can see, which size
+they have and which impact changes of the alignment have on them.
+
+\subsection{How does it work?}
+\subsubsection{Basic Commands}
+There are two basic commands:
+\begin{beschreibung}
+  \Befehl{reactant}[<pos>,<name>,<tikz>]{<formula>}
+  \Befehl{arrow}[<pos>,<type>,<length factor>,<name>,both,<tikz>]{<above>}\ma{<below>}
+\end{beschreibung}
+
+Schemes are created within the \env{rxn}{} environment. There you place reactants
+and arrows.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow{Ox.}{}
+  \reactant{ \chemfig{-[::30]=_[::-60]O} }
+ \end{rxn}
+\end{beispiel}
+
+When you don't use options reactants and arrows always are put to the right of
+the last object. With the option \code{<pos>} you can change this behaviour.
+\begin{beispiel}
+  % positioning using key words
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow[below]{Ox.}{}
+  \reactant[below]{ \chemfig{-[::30]=_[::-60]O} }
+ \end{rxn}
+ % positioning using an angle
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow[180]{}{Ox.}
+  \reactant[180]{ \chemfig{-[::30]=_[::-60]O} }
+ \end{rxn}
+\end{beispiel}
+
+\begin{table}
+ \centering
+ \begin{tabular}{>{\ttfamily}l*{2}{>{$}r<{$}}}
+  \toprule
+  {\normalfont key word} & \text{pos. angle} & \text{neg. angle} \\
+  \midrule
+  right       & 0   & \pm 360 \\
+  right above & 45  & -315 \\
+  above       & 90  & -270 \\
+  above left  & 135 & -225 \\
+  left        & 180 & -180 \\
+  below left  & 225 & -135 \\
+  below       & 270 & -90 \\
+  below right & 315 & -45 \\
+  \bottomrule
+ \end{tabular}
+ \caption{key words for positioning}\label{tab:keywords}
+\end{table}
+
+You can see in the last example that positioning can be realized through key
+words (see table~\ref{tab:keywords}) like \code{below} or by using the angle
+relative to the horizontal line. Every angle from the interval
+$[\ang{-360};\ang{360}]$. \ang{0} corresponds to \code{right} which is the default
+value. \emph{Positive angles} mean a turn \emph{counter clockwise}, negative ones
+a turn clockwise -- like you're used to in mathematics.
+
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow[20]{Ox.}{}
+  \reactant[20]{ \chemfig{-[::30]=_[::-60]O} }
+ \end{rxn}
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow[-20]{Ox.}{}
+  \reactant[-20]{ \chemfig{-[::30]=_[::-60]O} }
+ \end{rxn} 
+\end{beispiel}
+
+\subsubsection{Positioning}
+Reactants and arrows cannot only be positioned through key words and angles. They
+can refer to another reactant or arrow.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,start]{ \chemfig{R-[::30](-[::60]R|^1) (-[::-120]R|^2)-[::-60]OH} }
+  \arrow[40]{\tiny$\text{R}^1=\text{H}$} {\tiny$\text{R}^2=\text{H}$}
+  \reactant[40]{ \chemfig{R-[::30]=_[::-60]O} }
+  \arrow[start.0]{\tiny$\text{R}^1=\text{alkyl}$} {\tiny$\text{R}^2=\text{H}$}
+  \reactant{ \chemfig{R-[::30](-[::60]R)=_[::-60]O} }
+  \arrow[start.-40,-|>]{\tiny$\text{R}^1=\text{alkyl}$} {\tiny$\text{R}^2=\text{Alkyl}$}
+ \end{rxn}
+\end{beispiel}
+In the last example the first reactant got the \code{<name>} \code{start}. The
+arrows in lines 5 and 7 now could refer to it. A \emph{previously given name} can
+act as an anchor for later reactants or arrows, if the positioning is written like
+\code{<anchor>.<angle>}.
+
+Arrows can be given names, too. The anchor point of an arrow always is in the
+middle of the arrow line and has \emph{no} size.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{\chemfig{[:60]-(-[::60])=[::-60](-[::-60])-}}
+  \arrow[,,,arrow]{}{}
+  \reactant[arrow.90]{\ch{H2O}}
+ \end{rxn}
+\end{beispiel}
+
+Using this kind of positioning does \emph{not} break the chain.
+\begin{beispiel}[code only]
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \reactant{B}
+  \arrow[a.-90]{}{}
+  \reactant[-90]{C}
+  \arrow[a.180]{}{}
+  \reactant[180]{D}
+ \end{rxn}
+\end{beispiel}
+
+All seven objects of this example are logically speaking part of the same chain.
+The next object is placed to the right of the last one if no positioning is used.
+\begin{rxn}
+ \tikzset{nummer/.style={circle,fill=gray!30,draw=gray,minimum size=3.5mm}}
+ \reactant[,a]{A}\arrow[,,,pa]{}{}\reactant[,b]{B}
+ \arrow[a.-90,,,pb]{}{}\reactant[-90,c]{C}
+ \arrow[a.180,,,pc]{}{}\reactant[180,d]{D}
+ \anywhere{a.45,,nummer}{1}
+ \anywhere{pa.90,,nummer}{2}
+ \anywhere{b.45,,nummer}{3}
+ \anywhere{pb.0,,nummer}{4}
+ \anywhere{c.45,,nummer}{5}
+ \anywhere{pc.90,,nummer}{6}
+ \anywhere{d.45,,nummer}{7}
+\end{rxn}
+
+\subsubsection{Branches}
+To break a chain you use the command
+\begin{beschreibung}
+ \Befehl{branch}[<pos>,<name>,<tikz>]{<formulae>}
+\end{beschreibung}
+The positioning of a branch is slightly different from earlier objects, although
+the syntax is similar. A branch has two additional ways of positioning. Every
+positioning that refers to an anchor cause that the branch is not a part of the
+chain but is a real branch.
+\begin{description}
+ \item[\code{<angle>}] on the chain
+ \item[\code{<key>}] on the chain
+ \item[\code{<anchor>.<angle>}] not on the chain
+ \item[\code{on chain=going <key>}]on the chain
+ \item[\code{<key>=of <anchor>}] not on the chain
+\end{description}
+As \code{<key>} you again use the values from table~\ref{tab:keywords}.
+
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow{}{}
+  \reactant[,carbonyl]{ \chemfig{-[::30]=_[::-60]O} }
+  \branch[carbonyl.-90]{
+    \arrow[-90,<=>]{\ch{NH2R}}{}
+    \reactant[-90]{ \chemfig{-[::30]=_[::-60]N(-[6]H)-[::60]R} }
+  }
+  \arrow{}{}
+  \reactant{ \chemfig{-[::30](-[::60]OH)=_[::-60]O} }
+ \end{rxn}
+\end{beispiel}
+
+Please note that in the last example the arrow and the reactant placed after
+branch continue the original chain.
+\begin{beispiel}[code only]
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \reactant{B}
+  \branch[a.-90]{
+    \arrow[-90]{}{}
+    \reactant[-90]{C}
+  }
+  \arrow[a.180]{}{}
+  \reactant[180]{D}
+ \end{rxn}
+\end{beispiel}
+
+The chain is broken by the branch which starts a new chain itself.
+\begin{rxn}
+ \tikzset{nummer/.style={circle,fill=gray!30,draw=gray,minimum size=3.5mm,overlay}}
+ \reactant[,a]{A}\arrow[,,,pa]{}{}\reactant[,b]{B}
+ \branch[a.-90]{
+   \arrow[-90,,,pb]{}{}\reactant[-90,c]{C}
+    \anywhere{pb.0,,nummer}{a}
+    \anywhere{c.45,,nummer}{b}
+ }
+ \arrow[a.180,,,pc]{}{}\reactant[180,d]{D}
+ \anywhere{a.45,,nummer}{1}
+ \anywhere{pa.90,,nummer}{2}
+ \anywhere{b.45,,nummer}{3}
+ \anywhere{pc.90,,nummer}{4}
+ \anywhere{d.45,,nummer}{5}
+\end{rxn}
+
+Using \cmd{branch} allows to create schemes with several branches:
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \chemfig{-[::30]-[::-60]OH} }
+  \arrow{}{}
+  \reactant[,carbonyl]{ \chemfig{-[::30]=_[::-60]O} }
+  \arrow[-90]{}{}
+  \reactant[-90]{ \chemfig{-[::30](-[::60]OH)=_[::-60]O} }
+  \branch[right=of carbonyl]{
+    \arrow[,<=>,1.12]{\ch{NH2R}}{}
+    \reactant{ \chemfig{-[::30]=_[::-60]N(-[6]H)-[::60]R} }
+  }
+  \branch[below right=of carbonyl]{
+    \arrow[-45,<=>,1.12]{ \chemfig{[,.75]-[::30]-[::-60]OH} }{}
+    \reactant[-45]{ \chemfig{-[::30](-[::60]O-[::-60]-[::-60])-[::-60]OH} }
+  }
+  \arrow[carbonyl.90]{ \chemfig{[,.75]-[::30]=_[::-60]O}/\Hpl }{}
+  \reactant[90]{ \chemfig{-[::30](-[::60]OH)-[::-60]-[::60]=[::60]O} }
+  \arrow{$-\ch{H2O}$}{}
+  \reactant{ \chemfig{-[::30]=[::-60]-[::60]=[::60]O} }
+ \end{rxn}
+\end{beispiel}
+
+\subsubsection{Numbered Schemes}
+There is another environment to create schemes.
+\begin{beschreibung}
+ \Umg{rxnscheme}[<label>,<placement>,<alignment>,<skale factor>,<title>]{<caption>}
+\end{beschreibung}
+
+This is a floating environment for scheme, which can be given a \code{<caption>},
+a \code{<label>} and the common placement identifiers like \code{htp} (default).
+\begin{beispiel}[code and float]
+\begin{rxnscheme}{Keto-Enol-tautomerism}
+ \reactant{ \chemfig{=[::30]-[::-60]OH} }
+ \arrow[,<=>]{}{}
+ \reactant{ \chemfig{-[::30]=[::-60]O} }
+\end{rxnscheme}
+\end{beispiel}
+
+\subsection{Predefined Values}
+There are some predefined values that are basically due to my personal taste. But
+of course you can change them according to your requirements. For \paket{chemfig}%
+-formul\ae\ \emph{inside of \mychemistry environments} some values are predefined
+as follows:
+\begin{beispiel}[code only]
+ \setatomsep{1.8em}
+ \setcrambond{3pt}{0.5pt}{1pt}
+\end{beispiel}
+Outside the \mychemistry environments the defaults of \paket{chemfig} still are
+set.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{\chemfig{**6(------)}}
+ \end{rxn}
+ \chemfig{**6(------)}
+\end{beispiel}
+
+\mychemistry's defaults can be changed with these commands:
+\begin{beschreibung}
+ \Befehl{setbondlength}{<length>}
+ \Befehl{setbondshape}{<base length>}\ma{<dash thickness>}\ma{<dash spacing>}
+ \Befehl{setatomsize}{<font size>}
+\end{beschreibung}
+With these commands the parameters are changed \emph{for all following}
+\mychemistry environments. If you leave the arguments empty default values are
+restored. Default for \cmd{setatomsize} is \cmd{small}.
+
+\begin{beispiel}
+ \setbondlength{2.1em}\setbondshape{5pt}{1pt}{2pt}\setatomsize{\Large}
+ \begin{rxn}
+  \reactant{\chemfig{-[::30](<[::60])-[::-60](<:[::-60])-[::60]A}}
+ \end{rxn}
+ \setbondlength{}\setbondshape{}{}{}\setatomsize{}
+ \begin{rxn}
+  \reactant{\chemfig{-[::30](<[::60])-[::-60](<:[::-60])-[::60]A}}
+ \end{rxn}
+\end{beispiel}
+
+If you only want to change the parameters of a single environment you can use
+\paket{chemfig}'s commands and \LaTeX's fontsize commands \emph{inside the
+environment}.
+\begin{beispiel}
+ \begin{rxn}
+  \setatomsep{2.1em}\setcrambond{5pt}{1pt}{2pt}\Large
+  \reactant{\chemfig{-[::30](<[::60])-[::-60](<:[::-60])-[::60]A}}
+ \end{rxn}
+ \begin{rxn}
+  \reactant{\chemfig{-[::30](<[::60])-[::-60](<:[::-60])-[::60]A}}
+ \end{rxn}
+\end{beispiel}
+
+The default length of reaction arrows is \SI{4}{em}, the default line width is
+\code{semithick} and the default label distance is \SI{0.2}{em}. You can change
+these default values with the commands
+\begin{beschreibung}
+ \Befehl{setarrowlength}{<length>}
+ \Befehl{setarrowline}{<line width>}
+ \Befehl{setarrowlabel}{<label distance>}
+\end{beschreibung}
+or with
+\begin{beschreibung}
+ \befehl{mCsetup}{<options>} valid options are:
+ \Option{arrowlength}{<length>}
+ \Option{arrowline}{<line width>}
+ \Option{arrowlabel}{<label distance>}
+\end{beschreibung}
+
+\section{Advanced Usage, Usage with \TikZ}
+The biggest problem with \mychemistry usually is the correct positioning of
+reactants and arrows. Section~\ref{ssec:ausrichtungsfrage} looks a little bit
+into this topic.
+
+Some of the commands can be given \TikZ code as third optional argument. More
+precisely you can use the same \TikZ keys there as you would with a \cmd{node}
+inside a \code{tikzpicture}. If a node is placed with \cmd{node}\oa{<tikz>}%
+\da{<placement>}\ma{<anything>} then \code{<tikz>} is about the same in \eg
+\cmd{reactant}[,,<tikz>]{}. With this you can customize your scheme in many ways.
+
+\subsection{The Alignment Question}\label{ssec:ausrichtungsfrage}
+Since reactants, arrows and branches are aligned centered to the referred object
+the default alignment not always produces nice results.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant{ \chemname{\chemfig{*6(-=-=-=)}}{benzene \cmpd{benzene}} }
+  \arrow{}{}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+ \end{rxn}
+\end{beispiel}
+As you can see both reactants are not aligned equally to the arrow as far as the
+benzene ring is concerned. The first reactant seems to be shifted up. Trying to
+solve this with \TikZ code fails:
+
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,,yshift=-1em]{ \chemname{\chemfig{*6(-=-=-=)}}{benzene \cmpd{benzene}} }
+  \arrow{}{}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+ \end{rxn}
+\end{beispiel}
+This is, because the first reactant is shifted with the respect to the object it
+refers to. Since it is the first object on the chain itself it isn't shifted a
+all. The following arrow always is centered to the object before.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant{A}
+  \chemand
+  \reactant[,,yshift=1em]{B}
+  \arrow{}{}
+ \end{rxn}
+\end{beispiel}
+Since there is no possibility to change the alignment of the arrow itself what
+you can do is put it inside a branch.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant{A}
+  \chemand
+  \reactant[,,yshift=1em]{B}
+  \branch[,,yshift=-1em]{\arrow{}{}}
+ \end{rxn}
+ \begin{rxn}
+  \reactant{ \chemname{\chemfig{*6(-=-=-=)}}{benzene \cmpd{benzene}} }
+  \branch[,,yshift=1em]{\arrow{}{}}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+ \end{rxn}
+\end{beispiel}
+For the last example this isn't the best solution though because exact alignment
+needs lots of tries until you get the required result. There is another solution:
+an invisible bromine to the first benzene.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-[,,,,draw=none]\phantom{Br})-=)}}{benzene \cmpd{benzene}} }
+  \arrow{}{}
+  \reactant{ \chemname{\chemfig{*6(-=-=(-Br)-=)}}{bromobenzene \cmpd{bromobenzene}} }
+ \end{rxn}
+\end{beispiel}
+In other cases, too, an invisible substituent should be preferred over \TikZ code
+since it's easier and more precise:
+\begin{beispiel}
+ \makevisible
+ default:
+ \begin{rxn}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]OH}}
+  \chemand
+  \reactant{\chemfig{HO-[:30]-[:-30]-[:30]}}
+  \arrow{[\Hpl]}{\SI{200}{\celsius}}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]O-[:30]-[:-30]-[:30]}}
+ \end{rxn}
+ hydroxy groups at the same height through TikZ:
+ \begin{rxn}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]OH}}
+  \chemand[,,yshift=-1.2em]
+  \reactant[,,yshift=.12em]{\chemfig{HO-[:30]-[:-30]-[:30]}}
+  \branch[,,yshift=1.08em]{\arrow{[\Hpl]}{\SI{200}{\celsius}}}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]O-[:30]-[:-30]-[:30]}}
+ \end{rxn}
+ hydroxy groups at the same height through an invisible substituent:
+ \begin{rxn}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]OH}}
+  \chemand
+  \reactant{\chemfig{HO-[:30](=[2,,,,draw=none]\phantom{O})-[:-30]-[:30]}}
+  \arrow{[\Hpl]}{\SI{200}{\celsius}}
+  \reactant{\chemfig{-[:-30]-[:30](=[2]O)-[:-30]O-[:30]-[:-30]-[:30]}}
+ \end{rxn}
+\end{beispiel}
+
+I'm afraid that in many other cases you'll have to play with \code{xshift} and
+\code{yshift}, though, until the scheme looks the way you want.
+
+\subsection{Using \TikZ to Achieve Other Results}
+You could, just for fun?, change the looks of a molecule with \TikZ.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,,->,green!45!blue!55]{ \chemfig{*6(---(-)---)} }
+ \end{rxn}
+ \chemfig[->,green!45!blue!55]{*6(---(-)---)}
+\end{beispiel}
+The last example is not very good, of course, since you can achieve the same result
+using \paket{chemfig}'s own possibilities. But other cases are imaginable: for
+example one could define a style with which reactants are shown:
+\begin{beispiel}
+ \colorlet{mCgreen}{green!50!gray}
+ \colorlet{mCblue}{cyan!50!gray}
+ \colorlet{mCred}{magenta!50!gray}
+ \colorlet{mCyellow}{yellow!50!gray}
+ \begin{rxn}
+  \tikzset{reactant/.style={draw=#1,fill=#1!10,inner sep=1em,minimum height=10em,minimum width=12em,rounded corners}}
+  \reactant[,cytosine,reactant=mCred]{\chemfig{H-[:30]N*6(-(=O)-N=(-NH_2)-=-)}}
+  \anywhere{cytosine.-90,,yshift=-2mm}{Cytosine}
+  \reactant[,thymine,reactant=mCyellow]{\chemfig{H-[:30]N*6(-(=O)-N(-H)-(=O)-(-CH_3)=-)}}
+  \anywhere{thymine.-90,,yshift=-2mm}{Thymine}
+  \reactant[cytosine.-90,adenine,yshift=-2em,reactant=mCblue]{\chemfig{[:-36]*5(-N(-H)-*6(-N=-N=(-NH_2)--)--N=)}}
+  \anywhere{adenine.-90,Guanin,yshift=-2mm}{Adenine}
+  \reactant[,guanine,reactant=mCgreen]{\chemfig{[:-36]*5(-N(-H)-*6(-N=(-NH_2)-N(-H)-(=O)--)--N=)}}
+  \anywhere{guanine.-90,,yshift=-2mm}{Guanine}
+ \end{rxn}
+\end{beispiel}
+This way certain parts of a scheme could be emphasized:
+\begin{beispiel}
+ \begin{rxn}
+  \setatomsep{1.5em}
+  \colorlet{mCgreen}{green!50!gray}
+  \tikzset{emph/.style={draw=mCgreen,fill=mCgreen!10,inner sep=1em}}
+  \reactant[,lineOne]{\chemfig{R^1-[:30](=[@{b1}2]O)-[:-30]O-H}}
+  \arrow[,<=>]{\chemfig{@{Hpl1}\Hpl}}{}
+  \branch[,,emph]{
+    \reactant{\chemfig{R^1-[:30]@{C1}(-[2]O-[:30]H)(-[6,.5,,,draw=none]\fplus)-[:-30]O-H}}
+    \arrow[,<=>,2]{\chemfig{[:30]H-@{O1}O-[::-60]-R^2}}{}
+    \reactant{\chemfig{R^1-[:30](-[2]O-[:30]H)(-[6]@{O2}O-[:-150]H)-[:-30]@{O3}\chemabove{O}{\fplus}(-[@{b2}6]H)-[:30]-[:-30]R^2}}
+  }
+  \anywhere{lineOne.-90,lineTwo,xshift=-3em,yshift=-7em}{}
+  \arrow[lineTwo.0,<=>]{$-$\Hpl/\chemfig{@{Hpl2}\Hpl}}{}
+  \reactant{\chemfig{R^1-[:30](-[@{b3}2]O-[@{b4}:30]H)(-[@{b5}6]@{O4}\chembelow{O}{\fplus}(-[:-30]H)-[:-150]H)-[:-30]O-[:30]-[:-30]R^2}}
+  \arrow[,<=>,2]{$- \ch{H+} - \ch{H2O}$}{}
+  \reactant{\chemfig{R^1-[:30](=[2]O)-[:-30]O-[:30]-[:-30]R^2}}
+  \anywhere{lineTwo.-90}{
+    \elmove{b1}{10:5mm}{Hpl1}{135:1cm}
+    \elmove{O1}{135:1.5cm}{C1}{30:5mm}
+    \elmove{O2}{-90:3cm}{Hpl2}{90:2cm}
+    \elmove{b2}{0:5mm}{O3}{-10:5mm}
+    \elmove{b4}{-40:5mm}{b3}{0:5mm}
+    \elmove{b5}{-30:5mm}{O4}{-10:5mm}
+  }
+ \end{rxn}
+\end{beispiel}
+
+\section{Alphabetical Command Reference}
+In the following section every command is explained.
+
+\subsection{anywhere}\label{ssec:anywhere}
+Sometimes it might be useful to be able to place a reactant or anything else off
+the chain.
+\begin{beschreibung}
+ \Befehl{anywhere}{<pos>,<name>,<tikz>}\ma{<something>}
+\end{beschreibung}
+For this case there's \cmd{anywhere}. It is positioned with \code{<pos>} similar
+to \cmd{branch}.
+\begin{description}
+ \item[\code{<anchor>.<angle>}] not on the chain
+ \item[\code{on chain=going <key>}] on the chain
+ \item[\code{<key>=of <anchor>}] not on the chain
+\end{description}
+Please be aware that \code{<pos>} cannot be left empty.
+
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,carbonyl_A]{\chemfig{R_2C=O}}
+  \anywhere{above=of carbonyl_A}{\chemfig{H-[:-30]O-[:30]H}};
+ \end{rxn}
+\end{beispiel}
+You can use this command \eg for placing labels next to reactants.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,ketone]{\chemfig{H-\chemabove{C}{\hspace*{5mm}\scriptstyle\alpha}(-[2]H)(-[6,,,2]{}|{\textcolor{blue}H})-C(=[:60]\lewis{02,O})-[:-60]C|H_3}}
+  \anywhere{below=of ketone}{$+ \ch[format=\color{blue}]{OH-}$}
+  \arrow[,<=>]{\tiny slow}{}
+  \mesomeric[,mesomer]{
+    \reactant[,carbanion]{\chemfig{H_2|\chemabove[3pt]{\lewis{2,C}}{\fscrm}-C(=[:60]\lewis{02,O})-[:-60]C|H_3}}
+    \marrow
+    \reactant[,enolate]{\chemfig{H_2C=C(-[:60]\chemabove{\lewis{024,O}}{\hspace*{5mm}\fscrm})-[:-60]C|H_3}}
+  }
+  \anywhere{above=of enolate}{\tiny enolate ion}
+  \anywhere{above=of carbanion}{\tiny carbanion}
+  \anywhere{below=of mesomer}{$+ \ch[format=\color{blue}]{H2O}$}
+ \end{rxn}
+\end{beispiel}
+You can find many further examples for the usage of \cmd{anywhere} in \code{examples.tex}
+or \code{examples.pdf}, respectively.
+
+\subsection{\cmd{arrow}}\label{ssec:arrow}
+Reaction arrows are created with \cmd{arrow}.
+\begin{beschreibung}
+ \Befehl{arrow}[<pos>,<type>,<length factor>,<name>,both,<tikz>]{<above>}\ma{<below>}
+\end{beschreibung}
+
+\subsubsection{Options}
+There are a number of options to customize the arrows. The options must be used
+in the right order, separated with commas.
+\begin{enumerate}
+\item\code{<pos>} -- possible values:
+ \begin{rxn}
+  \setarrowlength{2.5em}
+  \dummy[a]
+  \arrow{}{}\reactant{right = \ang{0}}
+  \branch[above right=of a]{\arrow[above right]{}{}\reactant[above right,,overlay]{above right = \ang{45}}}
+  \branch[above=of a]{\arrow[above]{}{}\reactant[above,,overlay]{above = \ang{90}}}
+  \branch[above left=of a]{\arrow[above left]{}{}\reactant[above left,,overlay]{above left = \ang{135}}}
+  \branch[left=of a]{\arrow[left]{}{}\reactant[left,,overlay]{left = \ang{180} = \ang{-180}}}
+  \branch[below left=of a]{\arrow[below left]{}{}\reactant[below left,,overlay,xshift=-2em]{below left = \ang{225} = \ang{-135}}}
+  \branch[below=of a]{\arrow[below]{}{}\reactant[below,,overlay]{below = \ang{270} = \ang{-90}}}
+  \branch[below right=of a]{\arrow[below right]{}{}\reactant[below right,,overlay,xshift=2em]{below right = \ang{315} = \ang{-45}}}
+ \end{rxn}
+ Additionally you can use every angle from the interval $[\ang{-360};\ang{360}]$.
+ 
+ You can also use an angle with respect to an object that's been named with
+ \code{<name>}: \code{<name>.<angle>}. This means the arrow is placed in an
+ angle of \code{<angle>} next to \code{<name>}. You can find lots of examples in
+ \code{examples.tex} or\code{examples.pdf}, respectively.
+\item\code{<type>} -- possible values:
+ \begin{rxn}
+  \dummy[a]
+  \branch[below=of a,b,yshift=.5em]{\arrow{}{}\reactant{\ttfamily -\textgreater}}
+  \branch[below=of b,c,yshift=.5em]{\arrow[,<-]{}{}\reactant{\ttfamily \textless-}}
+  \branch[below=of c,d,xshift=.25em,yshift=.5em]{\arrow[,<->]{}{}\reactant{\ttfamily \textless-\textgreater}}
+  \branch[below=of d,e,yshift=.5em]{\arrow[,<=>]{}{}\reactant{\ttfamily \textless=\textgreater}}
+  \branch[below=of e,f,xshift=.25em,yshift=.5em]{\arrow[,<=>>]{}{}\reactant{\ttfamily \textless=\textgreater{}\textgreater}}
+  \branch[below=of f,g,yshift=.5em]{\arrow[,<<=>]{}{}\reactant{\ttfamily \textless{}\textless=\textgreater}}
+  \branch[below=of g,h,xshift=-.25em,yshift=.5em]{\arrow[,-|>]{}{}\reactant{\ttfamily -\textbar\textgreater}}
+  \branch[below=of h,,yshift=.5em]{\arrow[,-+>]{ }{ }\reactant{\ttfamily -+\textgreater}}
+ \end{rxn}
+\item\code{<length factor>} -- this factor multiplies with the arrow length
+  (\SI{4}{em} with factor = $1.0$, default)
+\item\code{<name>} -- can be used to give the arrow an anchor, to which another
+  object can refer.
+\item\code{both}-- this gives both nodes within which the labels are written the
+  same size.
+\item\code{<tikz>} -- you can modify the arrow with \TikZ keys. Not all \TikZ
+  keys have an effect, though. You can't shift arrows with \code{shift=<coord>},
+  for example.
+\end{enumerate}
+\begin{beispiel}
+  \begin{rxn}
+  \arrow[,,.25]{M}{}\arrow[,,.5]{MM}{}\arrow[,,.75]{MMM}{}\arrow{MMMM}{}\arrow[,,1.125]{MMMMM}{}\arrow[,,1.25]{MMMMM}{}
+ \end{rxn}
+\end{beispiel}
+Please note, that the labels \code{<above>} and \code{<below>} are rotated with
+the arrow. At an angle of \ang{180} \code{<above>} actually is \emph{below} the arrow.
+\begin{beispiel}
+ \begin{rxn}
+  \setarrowlength{2.5em}
+  \dummy[a]
+  \arrow{a}{b}
+  \arrow[a.45]{a}{b}
+  \arrow[a.90]{a}{b}
+  \arrow[a.135]{a}{b}
+  \arrow[a.180]{a}{b}
+  \arrow[a.225]{a}{b}
+  \arrow[a.270]{a}{b}
+  \arrow[a.315]{a}{b}
+ \end{rxn}
+\end{beispiel}
+
+You need to be aware of one or two points, when using the arrow type \code{-+>}:
+if you leave the labels empty, the arrow is the same as \code{->}. The first label
+is the one added to the reaction, the second the one subtracted. If you use only
+one of the labels only the corresponding arrow part is drawn.
+\begin{beispiel}
+ corresponds \verb"->":
+ \begin{rxn}
+  \arrow[,-+>]{}{}
+ \end{rxn}
+ add:
+ \begin{rxn}
+  \arrow[,-+>]{a}{}
+ \end{rxn}
+ subtract:
+ \begin{rxn}
+  \arrow[,-+>]{}{b}
+ \end{rxn}
+ both add and subtract:
+ \begin{rxn}
+  \arrow[,-+>]{a}{b}
+ \end{rxn}
+ Blanks are \emph{not} an empty label:
+ \begin{rxn}
+  \arrow[,-+>]{ }{ }
+ \end{rxn}
+\end{beispiel}
+
+You can change the appearance of an arrow with \TikZ keys:
+\begin{beispiel}
+ \begin{rxn}
+  \mCsetup{arrowlabel=.7em,arrowlength=6em}
+  \reactant{A}
+  \arrow[20,,,,,decorate,decoration=snake,blue]{a}{b}
+  \reactant[20]{A$^*$}
+ \end{rxn}
+\end{beispiel}
+
+\subsubsection{Alignment}
+If an arrow is placed inside a branch the alignment of the branch may be
+determined by the size of the label nodes. If the two labels have a different
+size, alignment can go wrong.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \branch[below=of a]{
+    \arrow[-90]{\chemfig{-[::30]-[::-60]OH}}{}
+  }
+ \end{rxn}
+ \makeinvisible
+\end{beispiel}
+By using the option \code{both} both nodes get the same size. This can correct
+the alignment.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \branch[below=of a]{
+   \arrow[-90,,,,both]{\chemfig{-[::30]-[::-60]OH}}{}
+  }
+ \end{rxn}
+ \makeinvisible
+\end{beispiel}
+There's more to the question of alignment in section~\ref{sssec:branch_ausrichtung}.
+
+\subsubsection{Appearance}
+You can change the general appearance of arrows with \cmd{setarrowlength}
+(section~\ref{ssec:setarrowlength}) and \cmd{setarrowline} (section~\ref{ssec:setarrowline}).
+
+\subsection{\cmd{branch}}\label{ssec:branch}
+\cmd{branch} is used to, well, create a branch to a reaction.
+\begin{beschreibung}
+ \Befehl{branch}[<pos>,<anchor>,<tikz>]{<branch code>}
+\end{beschreibung}
+For \cmd{branch} positioning an anchor is important. Let's take a look at an example:
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,start]{\chemfig{-[::30]=_[::-60](-[::-60])-[::60]}}
+  \arrow[,,.75]{\ch{HCl}}{}
+  \reactant{\chemfig{-[::30]-[::-60](-[::120]Cl)(-[::-60])-[::60]}}
+  \chemand
+  \reactant{\chemfig{-[::30](-[::60]Cl)-[::-60](-[::-60])-[::60]}}
+  \branch[below right=of start]{
+    \arrow[-45,,.75]{\ch{H2O}}{}
+    \reactant[-45]{\chemfig{-[::30]-[::-60](-[::120]OH)(-[::-60])-[::60]}}
+    \chemand
+    \reactant{\chemfig{-[::30](-[::60]OH)-[::-60](-[::-60])-[::60]}}
+  }
+ \end{rxn}
+\end{beispiel}
+The first reactant got the anchor \code{start} (line 2, also see
+section~\ref{ssec:reactant}). \cmd{branch} now refers to it in its alignment
+(line 7). If you don't use the alignment reference to an anchor you automatically
+refer to the last \cmd{reactant} or \cmd{arrow}. If you don't use alignment at all,
+then the branch is aligned to the right of the last \cmd{reactant} or \cmd{arrow}.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \chemfig{CH_2=CH-OH} }
+  \arrow[,<=>,.5]{}{}
+  \branch{ \reactant{ \chemfig{CH_3-CH=O} } }
+ \end{rxn}
+\end{beispiel}
+
+\subsubsection{Positioning}\label{sssec:branch_positionierung}
+There are several ways to position a branch. It can either be part of the chain
+or be a real branch.
+\begin{description}
+ \item[\code{<angle>}] on the chain
+ \item[\code{<key>}] on the chain
+ \item[\code{<anchor>.<angle>}] not on the chain
+ \item[\code{on chain=going <key>}] on the chain
+ \item[\code{<key>=of <anchor>}] not on the chain
+\end{description}
+
+The default behaviour is equal to \cmd{branch}[0]{}. In different situations
+different ways can be favoured. For example if you want to use \cmd{branch} to
+shift an arrow it can still be part of the chain.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{A}
+  \branch[,,yshift=1em]{\arrow{}{}}
+  \reactant[,,yshift=-1em]{B}
+ \end{rxn}
+\end{beispiel}
+
+If you like to start a real branch it \emph{does} matter which way you use.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a]{\chemfig{[:30]--[::-60]-OH}}
+  \arrow{}{}
+  \branch[a.-45]{\arrow[-45]{}{}}
+ \end{rxn}
+ \begin{rxn}
+  \reactant[,a]{\chemfig{[:30]--[::-60]-OH}}
+  \arrow{}{}
+  \branch[below right=of a]{\arrow[-45]{}{}}
+ \end{rxn}
+\end{beispiel}
+
+If a reactant isn't squared or circled \ang{-45} does not mean the same as
+``below right.''
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a,circle]{\chemfig{[:30]--[::-60]-OH}}
+  \arrow{}{}
+  \branch[a.-45]{\arrow[-45]{}{}}
+ \end{rxn}
+ \begin{rxn}
+  \reactant[,a,circle]{\chemfig{[:30]--[::-60]-OH}}
+  \arrow{}{}
+  \branch[below right=of a]{\arrow[-45]{}{}}
+ \end{rxn}
+\end{beispiel}
+
+\subsubsection{Alignment problems}\label{sssec:branch_ausrichtung}
+If an arrow has two arguments with different sizes and is placed inside a branch
+the alignment of the branch can go wrong. In this case the \cmd{arrow} key
+\code{both} isn't a solution since the smaller argument then is not placed next
+to the arrow but is centered in its node.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \branch[below=of a]{
+   \arrow[below,,,,both]{\chemfig{-[::30]-[::-60]OH}}{\Hpl}
+  }
+ \end{rxn}
+\end{beispiel}
+
+What you have to do is shift the branch using the \TikZ keys \code{xshift} and
+\code{yshift}.
+\begin{beispiel}
+ \makevisible
+ \begin{rxn}
+  \reactant[,a]{A}
+  \arrow{}{}
+  \branch[below=of a,,xshift=-1.35em]{
+   \arrow[below]{\chemfig{-[::30]-[::-60]OH}}{\Hpl}
+  }
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{chemand}}\label{ssec:chemand}
+The command
+\begin{beschreibung}
+ \Befehl{chemand}[<alignment>,<anchor>,<tikz>]
+\end{beschreibung}
+produces and places a $+$ in the same way \cmd{reactant} places arbitrary text.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{\chemfig{*6(------)}}
+  \chemand
+  \reactant{\ch{Br2}}
+  \arrow{$h\nu$}{}
+  \reactant{\chemfig{*6(--(-Br)----)}}
+  \chemand
+  \reactant{\ch{HBr}}
+ \end{rxn}
+\end{beispiel}
+The optional arguments for \cmd{chemand} and \cmd{reactant} are the same, see
+section~\ref{ssec:reactant} for \cmd{reactant}'s options.
+
+\subsection{\cmd{dummy}}\label{ssec:dummy}
+\cmd{dummy} creates an empty node. Up to v1.3 \cmd{arrow} needed to follow after
+a node since \cmd{arrow} internally uses \cmd*{tikzchainprevious}. If there was
+no node on the chain \emph{before} \cmd{arrow} was used an error was raised.
+The same thing happened with \cmd{branch}. By using \cmd{dummy} you could start
+a scheme with an arrow anyway.
+\begin{beispiel}[code only]
+ \begin{rxn}
+  \dummy\arrow{}{}
+ \end{rxn}
+\end{beispiel}
+\emph{This is \emph{not} necessary any more}. In some (alignment) cases an empty
+node still might be useful so the command still exists.
+
+\subsection{\cmd{elmove}}\label{ssec:elmove}
+\cmd{elmove} just is a wrapper for \paket{chemfig}'s \cmd*{chemmove}.
+\begin{beschreibung}
+ \Befehl{elmove}[<tikz>]{<start>}\ma{<start direction>}\ma{<end>}\ma{<end direction>}
+\end{beschreibung}
+This is expanding to
+\begin{beispiel}[code only]
+ \chemmove{\draw[<tikz>](<start>).. controls +(<start direction>) and +(<end direction>)..(<end>);}
+\end{beispiel}
+using \oa{->,red,shorten <=3pt,shorten >=1pt} as default for \code{<tikz>}. How
+you use \cmd*{chemmove} is described in the documentation of \chemfig.
+\begin{beispiel}
+ \begin{center}
+  \setatomsep{1.8em}
+  \chemfig{*6(=[@{e1}]-=-(-[:120]Br)(-[:60]H)-(-[:-30,.4,,,white]\oplus)-[@{e2}])}
+  \elmove{e1}{60:4mm}{e2}{0:4mm}
+ \end{center}
+\end{beispiel}
+You should use \cmd{elmove} \emph{only inside} of \cmd{anywhere}, \cmd{reactant}
+or \cmd{transition}. Otherwise you might get alignment errors.
+
+\subsection{\cmd{makeinvisible}}\label{ssec:makeinvisible}
+\begin{beschreibung}
+ \Befehl{makeinvisible}
+\end{beschreibung}
+\cmd{makeinvisible} restores the normal \mychemistry behaviour after \cmd{makevisible}
+(see section~\ref{ssec:makevisible}) has been used. \cmd{makeinvisible} only changes
+the looks of nodes following after it.
+
+\subsection{\cmd{makevisible}}\label{ssec:makevisible}
+\begin{beschreibung}
+ \Befehl{makevisible}
+\end{beschreibung}
+With \cmd{makevisible} you can visualize the nodes within which reactants, arrows
+and branches are set. This is useful when you're aligning branches, for example.
+You can see an example of the usage of \cmd{makevisible} in section~\ref{ssec:arrow}.
+Every kind of nodes is emphasized with a different colour: 
+
+\tikz[baseline=(X.base)]\node[draw=red!60](X){\cmd{reactant}{}};,
+\tikz[baseline=(X.base)]\node[draw=green!60](X){\cmd{arrow}{above}};,
+\tikz[baseline=(X.base)]\node[draw=blue!60](X){\cmd{arrow}{below}};
+and \tikz[baseline=(X.base)]\node[draw=cyan](X){\cmd{branch}{}};.
+Also see section~\ref{ssec:makeinvisible}.
+
+\cmd{makevisible} only changes the looks of nodes following after it ond only
+effects the group whithin which it is used.
+\begin{beispiel}
+ \begin{rxn}
+  \makevisible
+  \reactant[,a]{A}
+  \arrow{a}{b}
+  \branch[below=of a]{
+    \arrow[-90,,,,both]{a}{b}
+  }
+ \end{rxn}
+ \begin{rxn}
+  {\makevisible
+  \reactant{\chemfig{[:30]--[::-60]-OH}}
+  }
+  \reactant{\chemfig{[:30]--[::-60]-OH}}
+ \end{rxn}
+\end{beispiel}
+
+\emph{Please beware that \cmd{makevisible} \emph{only} has an effect if the
+package option \key{draft} is active}!
+
+\subsection{\cmd{marrow}}\label{ssec:marrow}
+\cmd{marrow} creates a double-headed arrow.
+\begin{beschreibung}
+ \Befehl{marrow}[<direction>]
+\end{beschreibung}
+It is a shortcut for \cmd{arrow}[<direction>,<->,.5]\ma{}\ma{}.
+
+\subsection{\cmd{mCsetup}}\label{ssec:mCsetup}
+With
+\begin{beschreibung}
+ \Befehl{mCsetup}{<keys>}
+\end{beschreibung}
+you can fully customize \mychemistry. For each of \mychemistry's commands going
+like \cmd{set<command>} except \cmd{setbondshape} there is a key \key{<command>}{<value>}.
+Additionally there is the key \key{align}{<value>} with which you can change the
+alignment behaviour of both \env{rxn}{} and \env{rxnscheme}{}, and the key
+\key{reset} with whith all values are reset to default.
+\begin{beispiel}
+ \mCsetup{
+  align=left,
+  arrowlabel=.7em,
+  arrowlength=3em,
+  arrowline=thick,
+  atomsize=\large,  
+  bondlength=3em,
+  mergelength=4em,
+  rcndist=2em
+  %rxnalign=right,
+  %schemealign=left
+ }
+ \setbondshape{4pt}{2pt}{1pt}
+ \begin{rxn}
+  \reactant{A}\arrow{a}{b}\reactant{\chemfig{A-(<[2])(<:[6])-B}}
+ \end{rxn}
+ \mCsetup{reset}
+ \begin{rxn}
+  \reactant{A}\arrow{a}{b}\reactant{\chemfig{A-(<[2])(<:[6])-B}}
+ \end{rxn}
+\end{beispiel}
+\cmd{mCsetup} as well as every other setup command only effects the group whithin
+which it is used.
+
+Here is a complete list of valid keys:
+\begin{beschreibung}
+ \Option{align}
+ \Option{arrowlabel}
+ \Option{arrowlength}
+ \Option{arrowline}
+ \Option{atomsize}
+ \Option{bondlength}
+ \Option{elmove}
+ \Option{mergelength}
+ \Option{rcndist}
+ \Option{reset}
+ \Option{rxnalign}
+ \Option{schemealign}
+\end{beschreibung}
+
+\subsection{\cmd{merge}}\label{ssec:merge}
+The \cmd{merge} command is used to merge different reaction chains. In order to
+do that the reactants that are to be merged must have an anchor name
+(\cmd{reactant}[,<anchor>]{}), similar with branches, see sections~\ref{ssec:reactant}
+and \ref{ssec:branch}) and be placed \emph{before} \cmd{merge}.
+\begin{beschreibung}
+ \Befehl{merge}[<label>,<direction>,<length>]{<target>}\ma{<start a>}\ma{<start b>}
+\end{beschreibung}
+\cmd{merge} has three optional and three mandatory arguments. The latter are the
+anchor names of the reactants that are to be merged.
+\begin{beispiel}
+ \begin{rxn}
+  \branch[,first]{
+   \reactant[,start_a]{\chemfig{-[:30]-[:-30]OH}}
+   \reactant[,start_b,xshift=9em]{\chemfig{-[:30]=[:-30]O}}
+  }
+  \branch[below=of first,target,yshift=-5em]{
+   \reactant{\chemfig{-[:30]-[:-30]O-[:30](-[2]OH)-[:-30]}}
+  }
+  \merge[\ch{[OH^-]}]{target}{start_a}{start_b}
+ \end{rxn}
+\end{beispiel}
+
+The default \code{<direction>} is \code{below}, other possible values are
+\code{right}, \code{left} and \code{above}. With \code{<length>} the length of
+the arrow from the point of merging to the tip can be changed. The default length
+is \SI{3}{em}. The default length can be changed with \cmd{setmergelength} or
+\cmd{mCsetup}.
+\begin{beispiel}
+ \begin{rxn}
+  \reactant[,start_a]{\chemfig{-[:30]-[:-30]OH}}
+  \branch[below=of start_a,start_b,yshift=-9em]{
+   \reactant{\chemfig{-[:30]=[:-30]O}}
+  }
+  \branch[right=of start_a,target,xshift=7em,yshift=-6em]{
+   \reactant{\chemfig{-[:30]-[:-30]O-[:30](-[2]OH)-[:-30]}}
+  }
+  \merge[\ch{[OH^-]},right,5em]{target}{start_a}{start_b}
+ \end{rxn}
+\end{beispiel}
+Since you have to place the reactants first it might be useful to know a little
+bit about involved lengths. There are three values which influence the needed
+distance between start points and the target reactant. There is the \emph{depth}
+of the involved reactants, the distance of the ``reaction nodes'' \emph{rcndist}
+(see section~\ref{ssec:setrcndist}) and the length of the \cmd{merge} arrow
+\emph{mergelength} (also see section~\ref{ssec:setmergelength}).
+\begin{rxn}
+ \node[above](a) at (0,0){A};
+ \node[above](b) at (10em,0){B};
+ \node[below](c) at (5em,-6em){C};
+ \merge{c}{a}{b}
+ \draw (-8.5em,1em) -- (-8.5em,-9em);
+ \foreach \x in {-1,0,1,2,3,4,5,6,7,8,9}{
+   \draw (-8.5em,-\x em) -- (-8.7em,-\x em);
+ }
+ \draw[<->,red] (10em,0)--node[midway,right,xshift=.2em]{rcndist (default: 1em)}(10em,-1em);
+ \draw[<->,red] (0,0)--(0,-1em);
+ \draw[<->,red] (5em,-5em)--(5em,-6em);
+ \draw[<->,blue] (6em,-2em) --node[midway,right,xshift=.2em]{mergelength (default: 3em)} (6em,-5em);
+ \draw[<->,green] ($(a.base)+(-.5em,0)$)--node[midway,left,xshift=-.2em]{reactant depth}++(0,.5em);
+\end{rxn}
+At last an example where two chains are merged.
+\begin{beispiel}
+ \begin{rxn}
+  \setatomsep{1.15em}\footnotesize
+  % chain 1
+   \reactant[,first]{ \chemfig{Cl-[:30,1.5]--[:-30,1.5]O-[:30,1.5]--[:-30,1.5]Cl}{} }
+   \arrow[,,.5]{}{}
+   \reactant[,start_above]{ \chemfig{O(-[:-150]**6(-----(-OH)-))-[:90]-[:30]-[:-30]O-[:30]-[:-30]-[:-90]O-[:-30]**6(-(-HO)-----)} }
+  % chain 2
+  \branch[below=of first,start_below,xshift=8em,yshift=-4em]{
+   \reactant{ \chemfig{**6((--[6,,,2]HO)-N-(--[6]OH)----)} }
+   \arrow[,,.5]{}{}
+   \reactant{ \chemfig{**6((--[6]Br)-N-(--[6]Br)----)} }
+  }
+  % target
+  \branch[right=of start_above,target,xshift=5em,yshift=-4em]{
+   \reactant[,c]{ \chemfig{O(-[:-150]**6(-----(-O?)-))-[:90]-[:30]**6(-N-(--[:-90]O-[:-30]**6(-(-O-[6]-[:-150]-[:150]O-[:-150]-[:150]?)-----))----)} }
+  }
+  % merging:
+  \merge[,right]{target}{start_above}{start_below}
+ \end{rxn}
+\end{beispiel}
+The usage of \cmd{merge} may require some playing with branches, \code{xshift}
+and \code{yshift} until you get the desired result.
+\begin{beispiel}
+ \begin{rxn}
+  \setatomsep{1.5em}
+  \reactant[,start_aa]{ \chemname{\chemfig{**6(---(-NH_2)---)}}{Anilin} }
+  \reactant[below,start_ab,yshift=-3em]{ \chemname{\ch{HNO2}}{salpetrige S\"aure} }
+  \branch[right=of start_aa,target_a,xshift=6em,yshift=-5em]{
+    \reactant{ \chemname{\chemfig{**6(---(-N|_2\fpch)---)}}{Diazoniumion} }
+  }% = start_ba
+  \branch[below=of target_a,start_bb,yshift=-3em]{
+    \reactant{ \chemname{\chemfig{**6(---(-NH_2)---)}}{Anilin} }
+  }
+  \branch[right=of target_a,target_b,xshift=6em,yshift=-5em]{
+    \reactant{ \chemname{\chemfig{N(-[:-150]**6(------))=N-[:-30]**6(---(-NH_2)---)}}{\iupac{\para\-Amino\|diazo\|benzol}} }
+  }
+  \merge[,right]{target_a}{start_aa}{start_ab}
+  \merge[,right]{target_b}{target_a}{start_bb}
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{mesomeric}}\label{ssec:mesomeric}
+The \cmd{mesomeric} command works just like \cmd{branch} (see section~\ref{ssec:branch})
+but places the formul\ae\ into square brackets.
+\begin{beschreibung}
+ \Befehl{mesomeric}[<pos>,<anchor>,<tikz>]{<formula>}
+\end{beschreibung}
+The resonance formul\ae\ are written into \code{<formula>}. With \cmd{marrow}
+(see section~\ref{ssec:marrow}) you can create the resonance arrows. If needed
+you can give an anchor (\code{<anchor>}) to \cmd{mesomeric} (also see
+section~\ref{ssec:branch}). Alignment is used the same way as with \cmd{reactant}.
+\begin{beispiel}
+ \begin{rxn}
+  \mesomeric{
+    \reactant{
+      \chemfig{*6(=[@{e1}]-=-(-[:120]X)(-[:60]H)-(-[:-30,.4,,,white]\fplus)-[@{e2}])}
+      \elmove{e1}{60:4mm}{e2}{0:4mm}
+    }
+    \marrow
+    \reactant{
+      \chemfig{*6(-(-[:90,.4,,,white]\fplus)-[@{e4}]=[@{e3}]-(-[:120]X)(-[:60]H)-=)}
+      \elmove{e3}{180:4mm}{e4}{150:4mm}
+    }
+    \marrow
+    \reactant{
+      \chemfig{*6(-=-(-[:-150,.4,,,white]\fplus)-(-[:120]X)(-[:60]H)-=)}
+    }
+   }
+ \end{rxn}
+\end{beispiel}
+
+Or vertical, too:
+\begin{beispiel}
+ \begin{rxn}
+  \mesomeric{
+    \reactant{ \chemfig{*6(=-=-=-)} }
+    \marrow[below]
+    \reactant[below]{ \chemfig{*6(-=-=-=)} }
+  }
+ \end{rxn}
+\end{beispiel}
+
+Or maybe a coordination complex?
+\begin{beispiel}
+ \begin{rxn}
+  \setatomsep{3em}
+  \mesomeric[,a]{
+    \reactant{ \chemfig{H_3\lewis{0,N}-[,1.35,,,dotted]{Cu}(-[2,,,,dotted]\lewis{6,N}H_3)(-[6,,,,dotted]\lewis{2,N}H_3)-[,1.2,,,dotted]\lewis{4,N}H_3} }
+  }
+  \node[above right=of a,yshift=-1em] {$2\fplus$};
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{reactant}}\label{ssec:reactant}
+\cmd{reactant} is something like the basic command.
+\begin{beschreibung}
+ \Befehl{reactant}[<pos>,<name>,<tikz>]{<formula>}
+\end{beschreibung}
+Formul\ae\ (\code{<formula>}) are written inside this command and can be named
+(\code{<name>}) for other objects to refer to. \code{<pos>} can either be one of
+these key words
+\begin{enumerate}
+ \item \code{right},
+ \item \code{above right},
+ \item \code{above},
+ \item \code{above left},
+ \item \code{left},
+ \item \code{below left},
+ \item \code{below},
+ \item \code{below right}
+\end{enumerate}
+or be an angle from the intervall $[\ang{-360};\ang{360}]$. You also can position
+it relativ to another object via \code{<anchor>.<angle>}. The default equals
+\cmd{reactant}[0]{}.
+\begin{beispiel}
+ below:
+ \begin{rxn}
+   \reactant{\ch{Br2}}
+   \reactant[-90]{\ch{Cl2}}
+ \end{rxn}
+
+ more than one reactant:
+ \begin{rxn}
+   \reactant{\ch{Br2}}
+   \reactant[-90]{\ch{I2}}
+   \reactant{\ch{Cl2}}
+ \end{rxn}
+
+ going down:
+ \begin{rxn}
+  \reactant{\ch{Br-Br}}
+  \arrow[-90,,.5]{$h\nu$}{}
+  \reactant[-90]{\ch{2 "\Lewis{0.,Br}"}}
+ \end{rxn}
+\end{beispiel}
+You can find many more examples in the file \code{examples.tex} or
+\code{examples.pdf}, respectively.
+
+\subsection{rxn (environment)}\label{ssec:rxn}
+\env{rxn}{} is a non-floating not numbered environment for reaction schemes. Per
+default all schemes are centered.
+\begin{beschreibung}
+ \Umg{rxn}[<alignment>,<scalefactor>]{...}
+\end{beschreibung}
+
+\subsubsection{Options}\label{sssec:rxn_optionen}
+\env{rxn}{} has two options which are to be used in the following order, separated
+by a comma:
+\begin{enumerate}
+ \item\code{<alignment>}: alignment behaviour of the \env{rxn}{} environment;
+   default is \code{center}.
+ \item\code{<scalefactor>}: factor by which the \env{rxn}{} environment is scaled;
+   default: \code{1.0}. Same behaviour as with \env{rxnscheme}, see
+   section~\ref{ssec:rxnscheme}.
+\end{enumerate}
+If you use the \code{<scalefactor>} option you might see strange effects on
+\paket{chemfig} formul\ae.
+
+\begin{beispiel}
+ \begin{rxn}[,.5]
+  \reactant{\chemfig{**6(------)}}
+ \end{rxn}
+\end{beispiel}
+Scaling does in general not affect the size of \paket{chemfig} formul\ae\ but
+does scale the aromaticity ring of benzene and similar molecules. This is not
+\mychemistry's fault:
+\begin{beispiel}
+ \chemfig[scale=.5]{**6(------)}
+\end{beispiel}
+This issue can be solved either by using the \emph{first} optional argument of
+\cmd*{chemfig} to undo the scaling or by using the \emph{second} optional argument
+to scale the rest of the molecule.
+\begin{beispiel}
+ \begin{rxn}[,.5]
+  \reactant{\chemfig[scale=2]{**6(------)}}
+  \reactant{\chemfig[][scale=.5]{**6(------)}}
+ \end{rxn}
+ \chemfig[scale=.5][scale=.5]{**6(------)}
+\end{beispiel}
+
+Alignment examples:
+\begin{beispiel}
+ \begin{rxn}[center]
+  \reactant{center}\arrow{}{}\reactant{centered}
+ \end{rxn}
+ \begin{rxn}[right]
+  \reactant{right}\arrow{}{}\reactant{raggedleft}
+ \end{rxn}
+ \begin{rxn}[left]
+  \reactant{left}\arrow{}{}\reactant{raggedright}
+ \end{rxn}
+\end{beispiel}
+
+\subsection{rxnscheme (environment)}\label{ssec:rxnscheme}
+\env{rxnscheme}{} is a floating environment for reaction schemes.
+\begin{beschreibung}
+ \Umg{rxnscheme}[<label>,<placement>,<alignment>,<scalefactor>,<name>]{\unskip\ma{<caption>} ...}
+\end{beschreibung}
+
+\subsubsection{Options}\label{sssec:rxnscheme_optionen}
+\env{rxnscheme}{} has five options which are to be used in the following order,
+separated by commas:
+\begin{enumerate}
+ \item\code{<label>}: Like every other floating environment \env{rxnscheme}{} can
+   be given a label. In order to do that you need to use the option \code{<label>}.
+   For example if you use
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[rs:schema]{<caption>}
+  ...
+ \end{rxnscheme}
+\end{beispiel}
+   you can refer to it by using \cmd*{ref}{rs:schema} as usual.
+ \item\code{<placement>}: With this option you can change the placement of the
+   float, \eg with \code{h}. The default value is \code{htp}.
+ \item\code{<alignment>}: This option changes the alignment of the scheme. You
+   can choose between \code{left}, \code{center} and \code{right}.
+ \item\code{<scalefactor>}: \env{rxnscheme}{} has another key with which the
+   scheme can be scaled. Please keep in mind that it doesn't affect the font size
+   and the size of \paket{chemfig}'s formul\ae. You can have strange effects on
+   \paket{chemfig}'s formul\ae\ if you use this key, though. See
+   section~\ref{sssec:rxn_optionen} for more information.
+ \item\code{<name>} This option changes the name of the actual scheme from
+   ``Reaction scheme'' into \code{<name>}.
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[,<placement>]{<caption>}
+  ...
+ \end{rxnscheme}
+\end{beispiel}
+\end{enumerate}
+
+\begin{beispiel}[code and float]
+ \begin{rxnscheme}[,,,2]{Big scheme}
+  \large\setatomsep{3.5em}
+  \reactant{ \chemfig{=[::30]-[::-60]OH} }
+  \arrow[,<=>]{}{}
+  \reactant{ \chemfig{-[::30]=[::-60]O} }
+ \end{rxnscheme}
+ \begin{rxnscheme}[,,,.5]{Small scheme}
+  \setatomsep{1.15em}\footnotesize
+  \reactant{ \chemfig{=[::30]-[::-60]OH} }
+  \arrow[,<=>]{}{}
+  \reactant{ \chemfig{-[::30]=[::-60]O} }
+ \end{rxnscheme}
+ \begin{rxnscheme}{center}
+  \reactant{center}\arrow{}{}\reactant{centered}
+ \end{rxnscheme}
+ \begin{rxnscheme}[,,right]{right}
+  \reactant{right}\arrow{}{}\reactant{raggedleft}
+ \end{rxnscheme}
+ \begin{rxnscheme}[,,left]{left}
+  \reactant{left}\arrow{}{}\reactant{raggedright}
+ \end{rxnscheme}
+\end{beispiel}
+
+\subsubsection{Customizing rxnscheme}
+\paragraph{Style}
+If you don't like the style of \env{rxnscheme}{} you can change it by using
+\begin{beschreibung}
+ \Befehl{floatstyle}{<new style>}
+ \Befehl{rxnfloat}
+\end{beschreibung}
+There are different possible styles, provided by the \paket{float} package:
+\begin{description}
+ \item[\code{plain}] without any special formatting, the caption is below the object.
+ \item[\code{plaintop}] like \code{plain} but the caption is placed above the object.
+ \item[\code{boxed}] the object is boxed, the caption placed below.
+ \item[\code{ruled}] the caption is placed above the object framed by two rules,
+   one above and one below, another rule frames the object below; default for
+   \env{rxnscheme}{}.
+\end{description}
+
+\begin{beispiel}[code and float]
+ \begin{rxnscheme}{ruled}
+  \reactant{default style}
+ \end{rxnscheme}
+ \floatstyle{boxed}
+ \restylefloat{rxnfloat}
+ \begin{rxnscheme}{boxed}
+  \reactant{framed object}
+ \end{rxnscheme}
+ \floatstyle{plain}
+ \restylefloat{rxnfloat}
+ \begin{rxnscheme}{plain}
+  \reactant{without any special formatting}
+ \end{rxnscheme}
+\end{beispiel}
+\floatstyle{ruled}
+\restylefloat{rxnfloat}
+
+\paragraph{Placement}
+Usually floating environments have an optional argument for their placement.
+The default placement is \code{htp}. If you want to change it into \code{H} or
+something, you can use
+\begin{beschreibung}
+ \Befehl{floatplacement}{rxnfloat}\ma{<placement>}
+\end{beschreibung}
+
+It's easier, though, loading \mychemistry with the \key{placement} option:
+\begin{beispiel}[code only]
+ \usepackage[placement=<placement>]{mychemistry}
+\end{beispiel}
+
+This will change the default placement behaviour from \code{htp} to \code{<placement>}.
+You can also change the placement behaviour of just one \env{rxnscheme}{} by
+using the placement option:
+\begin{beispiel}[code only]
+ \begin{rxnscheme}[,<placement>]{<caption>}
+  ...
+ \end{rxnscheme}
+\end{beispiel}
+
+\paragraph{Name}\label{par:rxnscheme_name}
+If you want to change the name of reaction scheme you can do that with
+\begin{beschreibung}
+ \Befehl{setschemename}{<new name>}
+\end{beschreibung}
+The default name is ``Reaction scheme'' but can change depending on the language
+you've loaded with \paket{babel}.
+
+\paragraph{Counter}
+The counter can be changed just as usual. For example by using
+\begin{beispiel}[code only]
+ \makeatletter
+ \@addtoreset{rxnfloat}{section}
+ \makeatletter
+ \renewcommand*\therxnscheme{\arabic{section}.\arabic{rxnscheme}}
+\end{beispiel}
+the counter is reset with every new section an looks like \code{section.rxnscheme}.
+
+\paragraph{List of Schemes}
+By writing
+\begin{beschreibung}
+ \Befehl{listof}{rxnfloat}\ma{<title>}
+\end{beschreibung}
+you can create a list of all schemes created with \env{rxnscheme}{}.
+\begin{beispiel}
+ \listof{rxnfloat}{Reaction schemes}
+\end{beispiel}
+
+\subsection{\cmd{setarrowlabel}}\label{ssec:setarrowlabel}
+The distance of arrow labels to the arrow has a default value of \SI{0.2}{em}.
+You can change this with
+\begin{beschreibung}
+ \Befehl{setarrowlabel}{<distance>}
+\end{beschreibung}
+into \code{<distance>}.
+\begin{beispiel}
+ \begin{rxn}
+  \arrow{a}{b}
+  \setarrowlabel{.5em}
+  \arrow{a}{b}
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{setarrowlength}}\label{ssec:setarrowlength}
+The default length of an reaction arrow is \SI{4}{em}. You can change this value
+with
+\begin{beschreibung}
+ \Befehl{setarrowlength}{<length>}
+\end{beschreibung}
+into \code{<length>}. Mind the fact that you have to use a length unit. If you
+leave the argument empty the length is reset to default.
+
+\subsection{\cmd{setatomsize}}\label{ssec:setatomsize}
+With
+\begin{beschreibung}
+ \Befehl{setatomsize}{<font size>}
+\end{beschreibung}
+you can change the font size of the atom groups. Default value is \cmd*{small}.
+If you leave the argument empty the size is reset to default.
+
+\subsection{\cmd{setbondlength}}\label{ssec:setbondlength}
+With
+\begin{beschreibung}
+ \Befehl{setbondlength}{<length>}
+\end{beschreibung}
+you can change \cmd{setatomsep}{<length>}= for all \paket{chemfig} formul\ae\
+\emph{inside} of the \mychemistry environments. The default value is \SI{1.8}{em}.
+If you leave the argument empty the length is reset to default.
+
+\subsection{\cmd{setarrowline}}\label{ssec:setarrowline}
+With the command
+\begin{beschreibung}
+ \Befehl{setarrowline}{<value>}
+\end{beschreibung}
+the thickness of the arrows can be customized. Possible values are
+ \begin{flushleft}
+ \begin{tikzpicture}
+   \draw[ultra thin] (0,0)--(1,0)node[right]{\ttfamily ultra thin};
+   \draw[very thin] (0,-.5)--(1,-.5)node[right]{\ttfamily very thin};
+   \draw[thin] (0,-1)--(1,-1)node[right]{\ttfamily thin};
+   \draw[semithick] (0,-1.5)--(1,-1.5)node[right]{{\ttfamily semithick} (default)};
+   \draw[thick] (0,-2)--(1,-2)node[right]{\ttfamily thick};
+   \draw[very thick] (0,-2.5)--(1,-2.5)node[right]{\ttfamily very thick};
+   \draw[ultra thick] (0,-3)--(1,-3)node[right]{\ttfamily ultra thick};
+ \end{tikzpicture}
+\end{flushleft}
+
+This command also applies to \cmd{merge}.
+
+\subsection{\cmd{setbondshape}}\label{ssec:setbondshape}
+With
+\begin{beschreibung}
+ \Befehl{setbondshape}{<base length>}\ma{<dash thickness>}\ma{<dash spacing>}
+\end{beschreibung}
+you can change \cmd{setcrambond}{<base length>}\ma{<dash thickness>}\ma{<dash spacing>}
+for all \paket{chemfig} formul\ae\ \emph{inside} of the \mychemistry environments.
+Default values are (in this order) \SI{3}{pt}, \SI{.5}{pt} and \SI{1}{pt}. If
+you leave an argument empty the value is reset to default.
+
+\subsection{\cmd{setelmove}}\label{ssec:setelmove}
+The command
+\begin{beschreibung}
+ \Befehl{setelmove}{<tikz>}
+\end{beschreibung}
+sets the default style that is used for the lines drawn by \cmd{elmove}. An empty
+argument resets to \code{->,red,shorten <=3pt,shorten >=1pt}.
+
+\subsection{\cmd{setmergelength}}\label{ssec:setmergelength}
+With
+\begin{beschreibung}
+ \Befehl{setmergelength}{<length>}
+\end{beschreibung}
+you can change the length of the \cmd{merge} arrow. More precisely you can change
+the length of the arrow from the point of line crossing to the arrow tip (see
+section~\ref{ssec:merge}). If you leave the argument empty the value is reset to
+default (\SI{3}{em}).
+
+\subsection{\cmd{setrcndist}}\label{ssec:setrcndist}
+The nodes within which the reactants an arrows are set have a certain distance
+between them. The default distance is \SI{1}{em}. If you want to change that you
+can use
+\begin{beschreibung}
+ \Befehl{setrcndist}{<length>}
+\end{beschreibung}
+If you leave the argument empty the distance is reset to \SI{1}{em}.
+\begin{beispiel}
+ \setrcndist{2em}
+ \begin{rxn}
+  \reactant{A}\arrow{}{}
+ \end{rxn}
+ \setrcndist{}
+ \begin{rxn}
+  \reactant{A}\arrow{}{}
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{setrxnalign}/\cmd{setschemealign}}\label{ssec:setrxnalign}\label{ssec:setschemealign}
+With the commands
+\begin{beschreibung}
+ \Befehl{setrxnalign}{<alignment>}
+ \Befehl{setschemealign}{<alignment>}
+\end{beschreibung}
+The default alignment behaviour of \env{rxn}{} and \env{rxnscheme}{} (see
+sections~\ref{sssec:rxn_optionen} and \ref{sssec:rxnscheme_optionen}) can be set.
+You can choose between \code{left}, \code{center} and \code{right}.
+
+If you leave the argument empty \mychemistry's default behaviour (\code{center})
+is restored.
+\begin{beispiel}
+ \setrxnalign{right}
+ \begin{rxn}
+  \reactant{A}\arrow{}{}\reactant{B}
+ \end{rxn}
+ \setrxnalign{}
+ \begin{rxn}
+  \reactant{A}\arrow{}{}\reactant{B}
+ \end{rxn}
+\end{beispiel}
+
+\subsection{\cmd{setschemename}}\label{ssec:setschemename}
+See page~\pageref{par:rxnscheme_name}.
+
+\subsection{\cmd{transition}}\label{ssec:transition}
+\cmd{transition} works exactly like \cmd{reactant} (see section~\ref{ssec:reactant}).
+\begin{beschreibung}
+ \Befehl{transition}[<pos>,<anchor>,<tikz>]{<formula>}
+\end{beschreibung}
+\begin{beispiel}
+ \begin{rxn}
+  \reactant{ \ch{H2 + I2} }
+  \arrow[below,<=>,.5]{}{}
+  \transition[below]{ \chemfig[dotted][]{H?-I-[2]I-[4]H?} }
+  \arrow[below,<=>,.5]{}{}
+  \reactant[below]{ \ch{2 HI} }
+ \end{rxn}
+\end{beispiel}
+
+\appendix
+\printindex
+\end{document}
\ No newline at end of file