mhchem update

git-svn-id: svn://tug.org/texlive/trunk@1731 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 417 insertions, 212 deletions

diff --git a/Master/texmf-dist/tex/latex/mhchem/mhchem.sty b/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
index b3eec4f0670..0aa67f2967e 100644
--- a/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
+++ b/Master/texmf-dist/tex/latex/mhchem/mhchem.sty
@@ -1,5 +1,5 @@
 %% mhchem.sty
-%% Copyright 2004-2005   M.a-r.t-i.n   H.e-n.s-e.l
+%% Copyright 2004-2006   M.a-r.t-i.n   H.e-n.s-e.l
 %
 % This work may be distributed and/or modified under the
 % conditions of the LaTeX Project Public License version 1.3
@@ -29,7 +29,7 @@
 % mhchem.pdf, legal.txt and whatsnew.txt.
 %
 %
-\ProvidesPackage{mhchem}[2005/07/15 v3.00 for typesetting chemical formulae]
+\ProvidesPackage{mhchem}[2006/06/23 v3.03 for typesetting chemical formulae]
 \RequirePackage{ifthen}
 \RequirePackage{calc}[1998/07/07]
 \RequirePackage{twoopt}
@@ -37,147 +37,45 @@
 \RequirePackage{keyval}
 \RequirePackage{graphics}
 
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%%%%%%%%   Options   %%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-\def\mhchem@option@version{0}
-\define@key{mhchem}{version}{\def\mhchem@option@version{#1}}
-\def\mhchem@option@mathfont{\mathrm}
-\def\mhchem@option@textfont{}
-\define@key{mhchem}{textfontcommand}{\def\mhchem@option@textfont{#1}}
-\define@key{mhchem}{textfontname}{\def\mhchem@option@textfont{\csname#1\endcsname}}
-\define@key{mhchem}{mathfontcommand}{\def\mhchem@option@mathfont{#1}}
-\define@key{mhchem}{mathfontname}{\def\mhchem@option@mathfont{\csname#1\endcsname}}
-\define@key{mhchem}{font}{%
-  \ifthenelse{\equal{sf}{#1}}{%
-    \def\mhchem@option@textfont{\sffamily}%
-    \def\mhchem@option@mathfont{\mathsf}%
-  }{\ifthenelse{\equal{}{#1}}{%
-    \def\mhchem@option@textfont{}%
-    \def\mhchem@option@mathfont{\mathrm}%
-  }{\PackageError{mhchem}{Font option `#1' unknown}}}%
-}
-\newlength\mhchem@option@minussidebearingleft
-\newlength\mhchem@option@minussidebearingright
-\setlength\mhchem@option@minussidebearingleft{0.06em}
-\setlength\mhchem@option@minussidebearingright{0.11em}
-\define@key{mhchem}{minus-sidebearing-left}{\setlength\mhchem@option@minussidebearingleft{#1}}
-\define@key{mhchem}{minus-sidebearing-right}{\setlength\mhchem@option@minussidebearingright{#1}}
-
-\providecommand\mhchemoptions[1]{\setkeys{mhchem}{#1}}
-
-%%% begin: standard keyval handling as in many other packages 
-\def\ProcessOptionsWithKV#1{%
-  \let\@tempc\relax
-  \let\mhchem@tempa\@empty
-  \@for\CurrentOption:=\@classoptionslist\do{%
-    \@ifundefined{KV@#1@\CurrentOption}%
-    {}%
-    {%
-      \edef\mhchem@tempa{\mhchem@tempa,\CurrentOption,}%
-      \@expandtwoargs\@removeelement\CurrentOption
-        \@unusedoptionlist\@unusedoptionlist
-    }%
-  }%
-  \edef\mhchem@tempa{%
-    \noexpand\setkeys{#1}{%
-      \mhchem@tempa\@ptionlist{\@currname.\@currext}%
-    }%
-  }%
-  \mhchem@tempa
-  \let\CurrentOption\@empty
-  \AtEndOfPackage{\let\@unprocessedoptions\relax}
-}
-\ProcessOptionsWithKV{mhchem}\relax
-%%% end:
-
-\ifnum0=\mhchem@option@version%
-  \PackageWarningNoLine{mhchem}{%
-    You did not specify a 'version' option for the mhchem\MessageBreak
-    package. This means you EITHER have an existing\MessageBreak
-    document and mhchem was updated to a newer version.\MessageBreak
-    Please check the mhchem manual in that case! OR, you\MessageBreak
-    are about to create a new document, in this case,\MessageBreak
-    please write \string\usepackage[version=2] in your preamble in\MessageBreak
-    order to use the most recent version of mhchem}%
-  \def\mhchem@option@version{1}%
-\else%
-\fi%
-
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-%
-
-\def\mhchem@option@usenonsimultaneoussubsuperscripts{0}%
-\def\mhchem@option@alwaystextmode{0}%
-
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%%%%%%%%            %%%%%%%%%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-\providecommand\cmath[1]{\ensuremath{#1}}%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%   misc    %%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+\newcommand*\cmath[1]{\ensuremath{\text{\ensuremath{#1}}}}%
 \DeclareMathSymbol{\mhchem@hyphen}{0}{operators}{45}
-
 \def\mhchem@empty{}  
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%   \ce   %%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-\ifnum1<\mhchem@option@version%
-  \newtoks\tok@mhchem@ce@i%
-  \newtoks\tok@mhchem@ce@ii%
-	\providecommand*{\cee}[1]{%
+\newtoks\tok@mhchem@ce@i%
+\newtoks\tok@mhchem@ce@ii%
+
+\newcommand*{\cee}[1]{%
+  \ifnum1<\mhchem@option@version%
     \def\mhchem@ce@out{}%
-	  %\ifx\mhchem@END#1\mhchem@END\else%
       {\mhchem@ce@v#1\mhchem@empty\\\mhchem@END\mhchem@ENDEND}%
-    %\fi%
     \ensuremath{%
 	    \mhchem@ce@out%
 	  }%
-	}%
-\fi%
-\providecommand*{\ce}[1]{%
-  \def\hyphen{\mhchem@hyphen}%
-	\bgroup%
-	\ifnum1<\mhchem@option@version%
-    \ifmmode\else\def\mhchem@option@alwaystextmode{1}\fi%
-	\fi%
-	\ifx\mhchem@END#1\mhchem@END\else%
-	  \ifmmode\else\mhchem@option@textfont\fi%
-	  \ensuremath{%
-	    \mhchem@ce@i#1 \mhchem@END\mhchem@ENDEND%
-	  }%
+	\else%
+	  \PackageWarningNoLine{mhchem}{%
+      The \string\cee{} command of mhchem is only available\MessageBreak
+      when you secify [version=2] or greater}%
 	\fi%
-	\egroup%
 }%
 
 \def\mhchem@ce@v#1\\#2#3\mhchem@ENDEND{%
   \ifx\mhchem@END#2%
-    %\ifx\mhchem@END#1\mhchem@END\else%
-      \mhchem@ce@vii#1&\mhchem@END\mhchem@ENDEND%
-    %\fi%
+    \mhchem@ce@vii#1&\mhchem@END\mhchem@ENDEND%
   \else%
     \mhchem@ce@vii#1&\mhchem@END\mhchem@ENDEND%
     \g@addto@macro\mhchem@ce@out{\\}%
     \mhchem@ce@v#2#3\mhchem@ENDEND%
   \fi%
 }     
-%
+
 \long\def\mhchem@ce@vii#1&#2#3\mhchem@ENDEND{%
   \ifx\mhchem@END#2%
     \g@addto@macro\mhchem@ce@out{\ce{#1}}%
@@ -190,6 +88,25 @@
 
 %%%
 
+\@ifundefined{hyphen}{%
+  \def\hyphen{}%
+}{}
+
+\DeclareRobustCommand*{\ce}[1]{%
+	\bgroup%
+  \protect\def\hyphen{\mhchem@hyphen}%
+  \ifnum1<\mhchem@option@version%
+    \ifmmode\else\def\mhchem@option@alwaystextmode{1}\fi%
+	\fi%
+	\ifx\mhchem@END#1\mhchem@END\else%
+	  \ifmmode\else\mhchem@option@textfont\fi%
+	  \ensuremath{%
+	    \mhchem@ce@i#1 \mhchem@END\mhchem@ENDEND%
+	  }%
+	\fi%
+	\egroup%
+}%
+
 \def\mhchem@ce@i#1#2 #3\mhchem@ENDEND{%
   \ifcat a#1 {\mhchem@ce@ii{#1#2}}%
   \else\ifx 1#1{\mhchem@ce@ii{#1#2}}%
@@ -315,12 +232,6 @@
   \else%
     \cf{#1}%
   \fi\fi\fi\fi%
-%    \ifthenelse{\equal{{{#1}}}{{{(^)}}}}{{}\mathop{\uparrow}{}}{%
-%    \ifthenelse{\equal{#1}{^}}{{}\mathop{\uparrow}{}}{%
-%    \ifthenelse{\equal{#1}{(v)}}{{}\mathop{\downarrow}{}}{%
-%    \ifthenelse{\equal{#1}{v}}{{}\mathop{\downarrow}{}}{%
-%      \cf{#1}%
-%    }%}}}%
 }%
 
 \def\mhchem@ce@cmath#1#2\mhchem@END{\cmath{#1}\cf{#2}}
@@ -332,50 +243,16 @@
 \setlength{\mhchem@arrowminlength}{1em}
 %TODO: adapt min length to each of the math modes
 
-\newcommandtwoopt*{\mhchem@gives}[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
-  \xrightarrow%
-    [{#2}]%
-    {{#1}}}}
-\newcommandtwoopt*{\mhchem@givesT}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@gives[\text{#1}][\text{#2}]}
-\newcommandtwoopt*{\mhchem@givesC}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@gives[\ce{#1}][\ce{#2}]}
-  
-\newcommandtwoopt*{\mhchem@givesleft}[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
-  \xleftarrow%
-    [{#2}]%
-    {{#1}}}}
-\newcommandtwoopt*{\mhchem@givesleftT}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@givesleft[\text{#1}][\text{#2}]}
-\newcommandtwoopt*{\mhchem@givesleftC}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@givesleft[\ce{#1}][\ce{#2}]}
-  
-\newcommandtwoopt*{\mhchem@mesomeric}[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
-  \ext@arrow 3399\leftrightarrowfill@%
-    {{#2}}%
-    {{#1}}}}
-\newcommandtwoopt*{\mhchem@mesomericT}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@mesomeric[\text{#1}][\text{#2}]}
-\newcommandtwoopt*{\mhchem@mesomericC}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@mesomeric[\ce{#1}][\ce{#2}]}
-  
-%%% idea taken from http://www.texnik.de/misc/harpoon.phtml
+%%% for font arrows
+%%%%% idea taken from http://www.texnik.de/misc/harpoon.phtml
 \def\mhchem@rightharpoonupfill@{\arrowfill@\relbar\relbar\rightharpoonup}
 \def\mhchem@leftharpoondownfill@{\arrowfill@\leftharpoondown\relbar\relbar}
-\newcommand*{\mhchem@xrightleftharpoons}[2][]{\mathrel{%
-  \rlap{\protect\raisebox{.22ex}{$\ext@arrow 3399\mhchem@rightharpoonupfill@{\hphantom{#1}}{#2}$}}%
-  \raisebox{-.22ex}{$\ext@arrow 3399\mhchem@leftharpoondownfill@{#1}{\hphantom{#2}}$}}}
-\newcommandtwoopt*{\mhchem@equilibrium}[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
-  \mhchem@xrightleftharpoons%
-  [{#2}]%
-  {{#1}}}}
-\newcommandtwoopt*{\mhchem@equilibriumT}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@equilibrium[\text{#1}][\text{#2}]}
-\newcommandtwoopt*{\mhchem@equilibriumC}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@equilibrium[\ce{#1}][\ce{#2}]}
-  
-\newsavebox{\mhchem@arrows@box}%
-\newcommand*{\mhchem@xlongrightshortleftharpoons}[2][]{\mathrel{%
+\newcommand*\mhchem@xrightleftharpoons[2][]{%
+  \mathrel{%
+  \rlap{\protect\raisebox{.22ex}{$\ext@arrow 3399\mhchem@rightharpoonupfill@{}{\mhchem@mathbox[#1]{#2}}$}}%
+  \raisebox{-.22ex}{$\ext@arrow 3399\mhchem@leftharpoondownfill@{#1}{\hphantom{#2}}$}}}%
+\newsavebox\mhchem@arrows@box%
+\newcommand*\mhchem@xlongrightshortleftharpoons[2][]{\mathrel{%
   \sbox{\mhchem@arrows@box}%
     {$\mkern9mu\ext@arrow 3399\mhchem@leftharpoondownfill@%
      {#1}{\hphantom{#2}\mkern-6mu\mkern-12mu}$}%
@@ -383,16 +260,7 @@
   \protect\raisebox{.22ex}{$\ext@arrow 3399\mhchem@rightharpoonupfill@%
     {\hphantom{\usebox{\mhchem@arrows@box}}\mkern-6mu}{#2}$}%
   }}
-\newcommandtwoopt*{\mhchem@equilibriumRight}[2][\hphantom{\makebox[\mhchem@arrowminlength]{}}][]{\ensuremath{%
-  \mhchem@xlongrightshortleftharpoons%
-  [{#2}]%
-  {{#1}}}}
-\newcommandtwoopt*{\mhchem@equilibriumRightT}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@equilibriumRight[\text{#1}][\text{#2}]}
-\newcommandtwoopt*{\mhchem@equilibriumRightC}[2][\hspace{\mhchem@arrowminlength}][]%
-  {\mhchem@equilibriumRight[\ce{#1}][\ce{#2}]}
-  
-\newcommand*{\mhchem@xshortrightlongleftharpoons}[2][]{\mathrel{%
+\newcommand*\mhchem@xshortrightlongleftharpoons[2][]{\mathrel{%
   \sbox{\mhchem@arrows@box}%
     {$\mkern9mu\ext@arrow 3399\mhchem@rightharpoonupfill@%
      {\hphantom{#1}\mkern-6mu\mkern-12mu}{#2}$}%
@@ -400,15 +268,213 @@
   \protect\raisebox{-.22ex}{$\ext@arrow 3399\mhchem@leftharpoondownfill@%
     {#1}{\hphantom{\usebox{\mhchem@arrows@box}}\mkern-6mu}$}%
   }}
-\newcommandtwoopt*{\mhchem@equilibriumLeft}[2][][\hspace{\mhchem@arrowminlength}]{\ensuremath{%
-  \mhchem@xshortrightlongleftharpoons%
-  [{#2}]%
-  {{#1}}}}
+%\newcommand*\mhchem@xleftrightarrow[2][]{\ext@arrow 3095\leftrightarrowfill@{#1}{#2}}
+  
+  
+%%% for pgf arrows
+\newcommand*\mhchem@rightarrow@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,0.85ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+      (0cm,0.575ex) -- ++(#1,0cm)
+    %\draw[cap=round, join=round, line width=0.07ex]
+    %  (#1,0.575ex)
+      arc (250:198:0.6ex) arc (198:250:0.6ex)
+      arc (110:162:0.6ex);
+  \end{tikzpicture}%
+}%
+\newcommand*\mhchem@leftarrow@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,0.85ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+      (#1,0.575ex) -- (0cm,0.575ex)
+    %\draw[cap=round, join=round, line width=0.07ex]
+    %  (0cm,0.575ex) 
+      arc (70:18:0.6ex) arc (18:70:0.6ex)
+      arc (-70:-18:0.6ex);
+  \end{tikzpicture}%
+}%
+\newcommand*\mhchem@leftrightarrow@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,0.85ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+        (0cm,0.575ex) 
+        arc (70:18:0.6ex) arc (18:70:0.6ex)
+        arc (-70:-18:0.6ex) arc (-18:-70:0.6ex)
+        -- ++(#1,0cm)
+        arc (250:198:0.6ex) arc (198:250:0.6ex) 
+        arc (110:162:0.6ex);
+  \end{tikzpicture}%
+}%
+\newcommand*\mhchem@leftrightharpoon@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,1ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+        (0cm,0.575ex+0.22ex) -- ++(#1,0cm) arc (250:198:0.9ex);  
+    \draw[cap=round, join=round, line width=0.09ex]
+        (#1,0.575ex-0.22ex) -- ++(-#1,0cm) arc (70:18:0.9ex);
+  \end{tikzpicture}%
+}%      
+\newcommand*\mhchem@longrightshortleftharpoons@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,1ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+        (0.0cm,0.575ex+0.22ex) -- ++(#1,0cm) arc (250:198:0.9ex);  
+    \draw[cap=round, join=round, line width=0.09ex]
+        (#1+0.5em-1em,0.575ex-0.22ex) -- (0.5em,0.575ex-0.22ex) arc (70:18:0.9ex);
+  \end{tikzpicture}%
+}% 
+\newcommand*\mhchem@shortrightlongleftharpoons@pgf[1]{%
+  \begin{tikzpicture}[baseline]%
+    \draw[use as bounding box] (0,0) (#1,1ex);
+    \draw[cap=round, join=round, line width=0.09ex]
+        (0.5em,0.575ex+0.22ex) -- ++(#1-1em,0cm) arc (250:198:0.9ex);  
+    \draw[cap=round, join=round, line width=0.09ex]
+        (#1,0.575ex-0.22ex) -- ++(-#1,0cm) arc (70:18:0.9ex);
+  \end{tikzpicture}%
+}%
+
+\newlength{\mhchem@arrowlength@pgf}
+\newlength{\mhchem@arrowminlength@pgf}
+%TODO: use \mhchem@arrowminlength
+\def\mhchem@labeledarrow@pgf#1#2#3#4#5#6#7{% 1-4 muskips 5 arrow 6 text above 7 below
+  \setlength\mhchem@arrowlength@pgf{\widthof{\ensuremath{%
+    \mkern#3mu%
+    \mathop{}%
+    \limits%
+    \@ifnotempty{#7}{^{\if0#1\else\mkern#1mu\fi%
+                       #7\if0#2\else\mkern#2mu\fi}}%
+    \@ifnotempty{#6}{_{\if0#1\else\mkern#1mu\fi%
+                       #6\if0#2\else\mkern#2mu\fi}}%	        
+    \mkern#4mu%
+  }}}%
+  %
+  \setlength\mhchem@arrowminlength@pgf{10pt+0.5em}%
+  \ifthenelse{\equal{hhleftrightarrow}{#5}}{\setlength\mhchem@arrowminlength@pgf{10pt+0.7em}}{}%
+  \ifthenelse{\equal{hhleftrightharpoon}{#5}}{\setlength\mhchem@arrowminlength@pgf{10pt+0.7em}}{}%
+  \ifthenelse{\equal{mhchem@longrightshortleftharpoons@pgf}{#5}}{
+    \setlength\mhchem@arrowminlength@pgf{1.85em}%
+    \setlength\mhchem@arrowlength@pgf{\widthof{\ensuremath{%
+      \mkern#3mu%
+      \mathop{}%
+      \limits%
+      \@ifnotempty{#7}{^{\if0#1\else\mkern#1mu\fi%
+                         #7\if0#2\else\mkern#2mu\fi}}%
+      \@ifnotempty{#6}{_{\if0#1\else\mkern#1mu\fi%
+                         \hspace{1em}% %%
+                         #6\if0#2\else\mkern#2mu\fi}}%	        
+      \mkern#4mu%
+    }}}%
+  }{}%
+  \ifthenelse{\equal{mhchem@shortrightlongleftharpoons@pgf}{#5}}{
+    \setlength\mhchem@arrowminlength@pgf{1.85em}%
+    \setlength\mhchem@arrowlength@pgf{\widthof{\ensuremath{%
+      \mkern#3mu%
+      \mathop{}%
+      \limits%
+      \@ifnotempty{#7}{^{\if0#1\else\mkern#1mu\fi%
+                         \hspace{1em}% %%
+                         #7\if0#2\else\mkern#2mu\fi}}%
+      \@ifnotempty{#6}{_{\if0#1\else\mkern#1mu\fi%
+                         #6\if0#2\else\mkern#2mu\fi}}%	        
+      \mkern#4mu%
+    }}}%
+  }{}%
+  %	        
+  \ifdim\mhchem@arrowlength@pgf<\mhchem@arrowminlength@pgf%
+    \setlength\mhchem@arrowlength@pgf{\mhchem@arrowminlength@pgf}%
+  \fi%
+  \mathrel{\mkern#3mu\mathop{\csname#5\endcsname{\mhchem@arrowlength@pgf}%
+    }%
+    \limits
+    \@ifnotempty{#7}{^{\if0#1\else\mkern#1mu\fi%
+                       #7\if0#2\else\mkern#2mu\fi}}%
+    \@ifnotempty{#6}{_{\if0#1\else\mkern#1mu\fi%
+                       #6\if0#2\else\mkern#2mu\fi}}%
+    \mkern#4mu%
+    }%}
+}%       
+	  		  
+\newcommandtwoopt*\mhchem@gives[2][][]{}
+\newcommandtwoopt*\mhchem@givesleft[2][][]{}
+\newcommandtwoopt*\mhchem@mesomeric[2][][]{}
+\newcommandtwoopt*\mhchem@equilibrium[2][][]{}
+\newcommandtwoopt*\mhchem@equilibriumRight[2][][]{}
+\newcommandtwoopt*\mhchem@equilibriumLeft[2][][]{}
+
+\newcommand\mhchem@definearrows[1]{%
+  %%% font
+  \ifthenelse{\equal{#1}{font}}{%
+		\renewcommandtwoopt*\mhchem@gives[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
+		  \xrightarrow%
+		    [{##2}]%
+		    {##1}}}%
+		\renewcommandtwoopt*\mhchem@givesleft[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
+		  \xleftarrow%
+		    [{##2}]%
+		    {##1}}}%
+		\renewcommandtwoopt*\mhchem@mesomeric[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
+		  \ext@arrow 3399\leftrightarrowfill@%
+		  {##2}%
+		  {##1}}}%
+		\renewcommandtwoopt*{\mhchem@equilibrium}[2][\hspace{\mhchem@arrowminlength}][]{\ensuremath{%
+		  \mhchem@xrightleftharpoons%
+		  [{##2}]%
+		  {##1}}}%
+		\renewcommandtwoopt*{\mhchem@equilibriumRight}[2][\hphantom{\makebox[\mhchem@arrowminlength]{}}][]{\ensuremath{%
+		  \mhchem@xlongrightshortleftharpoons%
+		  [{##2}]%
+		  {##1}}}%
+    \renewcommandtwoopt*{\mhchem@equilibriumLeft}[2][][\hspace{\mhchem@arrowminlength}]{\ensuremath{%
+		  \mhchem@xshortrightlongleftharpoons%
+		  [{##2}]%
+		  {##1}}}%
+  }{%%% pgf
+    \ifthenelse{\equal{#1}{pgf}}{%
+	    \renewcommandtwoopt*\mhchem@gives[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{1.5}{5}{1.5}{1}{mhchem@rightarrow@pgf}{##2}{##1}}}%
+	    \renewcommandtwoopt*\mhchem@givesleft[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{5}{1.5}{1}{1.5}{mhchem@leftarrow@pgf}{##2}{##1}}}%
+	    \renewcommandtwoopt*\mhchem@mesomeric[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{5}{5}{1}{1}{mhchem@leftrightarrow@pgf}{##2}{##1}}}%
+	    \renewcommandtwoopt*\mhchem@equilibrium[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{6}{6}{1}{1}{mhchem@leftrightharpoon@pgf}{##2}{##1}}}%
+	    \renewcommandtwoopt*\mhchem@equilibriumRight[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{6}{6}{1}{1}{mhchem@longrightshortleftharpoons@pgf}{##2}{##1}}}%
+	    \renewcommandtwoopt*\mhchem@equilibriumLeft[2][][]%
+	      {\ensuremath{\mhchem@labeledarrow@pgf{6}{6}{1}{1}{mhchem@shortrightlongleftharpoons@pgf}{##2}{##1}}}%
+	 	}{%
+	    \PackageError{mhchem}{The option font=#1 is not supported}%
+	  }%
+  }%
+}
+
+\newcommandtwoopt*\mhchem@givesT[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@gives[\text{#1}][\text{#2}]}%
+\newcommandtwoopt*\mhchem@givesC[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@gives[\ce{#1}][\ce{#2}]}%
+\newcommandtwoopt*\mhchem@givesleftT[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@givesleft[\text{#1}][\text{#2}]}%
+\newcommandtwoopt*\mhchem@givesleftC[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@givesleft[\ce{#1}][\ce{#2}]}%
+\newcommandtwoopt*\mhchem@mesomericT[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@mesomeric[\text{#1}][\text{#2}]}%
+\newcommandtwoopt*\mhchem@mesomericC[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@mesomeric[\ce{#1}][\ce{#2}]}%
+\newcommandtwoopt*{\mhchem@equilibriumT}[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@equilibrium[\text{#1}][\text{#2}]}
+\newcommandtwoopt*{\mhchem@equilibriumC}[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@equilibrium[\ce{#1}][\ce{#2}]}
+\newcommandtwoopt*{\mhchem@equilibriumRightT}[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@equilibriumRight[\text{#1}][\text{#2}]}
+\newcommandtwoopt*{\mhchem@equilibriumRightC}[2][\hspace{\mhchem@arrowminlength}][]%
+  {\mhchem@equilibriumRight[\ce{#1}][\ce{#2}]}
 \newcommandtwoopt*{\mhchem@equilibriumLeftT}[2][][\hspace{\mhchem@arrowminlength}]%
   {\mhchem@equilibriumLeft[\text{#1}][\text{#2}]}
 \newcommandtwoopt*{\mhchem@equilibriumLeftC}[2][][\hspace{\mhchem@arrowminlength}]%
   {\mhchem@equilibriumLeft[\ce{#1}][\ce{#2}]}
 
+
 %%%%%%%%%%
 % bonds - basic definition see in \cf
 \newlength\mhchem@bondwidth%
@@ -484,9 +550,10 @@
 %%%%%%%%%%   \cf   %%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \newtoks\mhchem@cf@sup%
+\newtoks\mhchem@cf@number
 \newtoks\tok@mhchem@cf@i%
 
-\providecommand*{\cf}[2][]{%
+\newcommand*{\cf}[2][]{%
 	\bgroup%
 	\def\sbond{{\ensuremath{-}}}%
 	\def\dbond{\rlap{\protect\raisebox{.2ex}{\sbond}}\protect\raisebox{-.2ex}{\sbond}}%
@@ -498,13 +565,18 @@
 	  \edef\mhchem@mathortext##1{\noexpand\text{##1}}%
 	  \edef\mhchem@mathortext@ii##1##2{##2}%
 	\else%
-	  \edef\mhchem@mathortext##1{\ifmmode\noexpand\mhchem@option@mathfont{##1}\else\noexpand\text{##1}\fi}%
-	  \edef\mhchem@mathortext@ii##1##2{\ifmmode\noexpand\mhchem@option@mathfont{##1}\else ##2\fi}%
+	  \ifnum1<\mhchem@option@version%
+	    \edef\mhchem@mathortext##1{\ifmmode\noexpand\mhchem@option@mathfont{##1}\else\noexpand\text{##1}\fi}%
+	    \edef\mhchem@mathortext@ii##1##2{\ifmmode\noexpand\mhchem@option@mathfont{##1}\else ##2\fi}%
+	  \else
+      \edef\mhchem@mathortext##1{\ifmmode ##1\else\noexpand\text{##1}\fi}%
+      \edef\mhchem@mathortext@ii##1##2{\ifmmode ##1\else ##2\fi}%
+	  \fi%
 	\fi%
 	\ifmmode\else\mhchem@option@textfont\fi%
 	\ensuremath{%
 	\def\mhchem@cf@element{}%
-	\def\mhchem@cf@number{}%
+	%\def\mhchem@cf@number{}%
 	%\def\mhchem@cf@sup{}%
 	\def\mhchem@cf@presub{}%
 	\def\mhchem@cf@presup{}%
@@ -527,20 +599,21 @@
   \if\mhchem@cf@state s%
   %
   \else\if\mhchem@cf@state 1%
-    {\mhchem@mathortext{\expandafter\mhchem@cf@frac\mhchem@cf@number/\mhchem@END}}%
+    {\mhchem@mathortext{\expandafter\mhchem@cf@frac\the\mhchem@cf@number/\mhchem@END}}%
   \else\if\mhchem@cf@state n%
-    {\mhchem@mathortext{\expandafter\mhchem@cf@frac\mhchem@cf@number/\mhchem@END}}%
+    {\mhchem@mathortext{\expandafter\mhchem@cf@frac\the\mhchem@cf@number/\mhchem@END}}%
   \else%
     \if\mhchem@option@usenonsimultaneoussubsuperscripts 0%
       \mhchem@chemfive{\mhchem@cf@presup}{\mhchem@cf@presub}%
-        {\mhchem@cf@element}{\mhchem@cf@number}{\the\mhchem@cf@sup}{}%
+        {\mhchem@cf@element}{\the\mhchem@cf@number}{\the\mhchem@cf@sup}{}%
     \else%
       \mhchem@chemfive{\mhchem@cf@presup}{\mhchem@cf@presub}%
-        {\mhchem@cf@element}{\mhchem@cf@number}{}{\the\mhchem@cf@sup}%
+        {\mhchem@cf@element}{\the\mhchem@cf@number}{}{\the\mhchem@cf@sup}%
     \fi%
   \fi\fi\fi%
   \def\mhchem@cf@element{}%
-  \def\mhchem@cf@number{}%
+  %
+  \mhchem@cf@number{}%
   %
   \mhchem@cf@sup{}%
   \def\mhchem@cf@presub{}%
@@ -618,35 +691,35 @@
     \mhchem@cf@output%
   \else%
       \if\mhchem@cf@state e%
-        \tok@mhchem@cf@i=\expandafter{\mhchem@cf@replaceminus{#1}}%
         \mhchem@cf@sup=\expandafter{\the\mhchem@cf@sup%
-        \expandafter\mhchem@cf@replacedot\expandafter{\the\tok@mhchem@cf@i}}%
+          \expandafter\mhchem@cf@replacedot\expandafter{\mhchem@cf@replaceminus{#1}}}%
+        %
+        %
+        %
+        %
         \def\mhchem@cf@state{+}%
       \else\if\mhchem@cf@state E%
         \mhchem@cf@sup=\expandafter{\the\mhchem@cf@sup%
           \mhchem@mathortext@ii{\mhchem@option@mathfont{#1}}{#1}}%
         \def\mhchem@cf@state{+}%
       \else\if\mhchem@cf@state p%
-        \edef\mhchem@cf@presup{\mhchem@cf@presup%
-          %\mhchem@cf@replaceminus{
-          #1}%
-          %}%
+        \g@addto@macro\mhchem@cf@presup{#1}%
         \def\mhchem@cf@state{*}%
       \else\if\mhchem@cf@state P%
         \edef\mhchem@cf@presup{\mhchem@cf@presup%
           \mhchem@mathortext@ii{\mhchem@option@mathfont{#1}}{#1}}%
         \def\mhchem@cf@state{*}%
       \else\if\mhchem@cf@state f%
-        \g@addto@macro\mhchem@cf@number{#1}%
+        \mhchem@cf@number=\expandafter{\the\mhchem@cf@number#1}%
         \def\mhchem@cf@state{+}%
       \else\if\mhchem@cf@state F%
-        \if\mhchem@END\mhchem@cf@number\mhchem@END%
-        \else\edef\mhchem@cf@number{\mhchem@cf@number\,}\fi%
-        \edef\mhchem@cf@number{\mhchem@cf@number%
+        \if\mhchem@END\the\mhchem@cf@number\mhchem@END%
+        \else\mhchem@cf@number=\expandafter{\the\mhchem@cf@number\,}\fi%
+        \mhchem@cf@number=\expandafter{\the\mhchem@cf@number%
           \mhchem@mathortext@ii{\mhchem@option@mathfont{#1}}{#1}}%
         \def\mhchem@cf@state{+}%
       \else\if\mhchem@cf@state q%
-        \edef\mhchem@cf@presub{\mhchem@cf@presub #1}%
+        \g@addto@macro\mhchem@cf@presub{#1}%
         \def\mhchem@cf@state{*}%
       \else\if\mhchem@cf@state Q%
         \edef\mhchem@cf@presub{\mhchem@cf@presub%
@@ -747,7 +820,7 @@
                 \def\mhchem@cf@state{2}%
               \fi\fi%
             \fi%
-            \edef\mhchem@cf@number{\mhchem@cf@number #1}%
+            \mhchem@cf@number=\expandafter{\the\mhchem@cf@number #1}%
           \else\ifcat a\noexpand#1%
             \if\mhchem@cf@state a%
             \else%
@@ -764,20 +837,27 @@
               \if\mhchem@cf@state s\def\mhchem@cf@state{p}%
               \else\if\mhchem@cf@state 1\mhchem@cf@output\def\mhchem@cf@state{p}%
               \else\if\mhchem@cf@state *\def\mhchem@cf@state{p}%
-              \else\def\mhchem@cf@state{e}%
+              \else%
+                \if\mhchem@END\the\mhchem@cf@sup\mhchem@END%
+                  \else\mhchem@cf@sup=\expandafter{\the\mhchem@cf@sup\,}\fi%
+                \def\mhchem@cf@state{e}%
               \fi\fi\fi%
             \else\if^\noexpand#1%
               \if\mhchem@cf@state s\def\mhchem@cf@state{p}%
               \else\if\mhchem@cf@state 1\mhchem@cf@output\def\mhchem@cf@state{p}%
               \else\if\mhchem@cf@state *\def\mhchem@cf@state{p}%
-              \else\def\mhchem@cf@state{e}%
+              \else%
+                \if\mhchem@END\the\mhchem@cf@sup\mhchem@END%
+                  \else\mhchem@cf@sup=\expandafter{\the\mhchem@cf@sup\,}\fi%
+                \def\mhchem@cf@state{e}%
               \fi\fi\fi%
             \else\ifcat _\noexpand#1%
               \if\mhchem@cf@state s\def\mhchem@cf@state{q}%
               \else\if\mhchem@cf@state 1\mhchem@cf@output\def\mhchem@cf@state{q}%
               \else\if\mhchem@cf@state *\def\mhchem@cf@state{q}%
+              \else\if\mhchem@cf@state 2\mhchem@cf@number=\expandafter{\the\mhchem@cf@number\,}\def\mhchem@cf@state{f}%
               \else\def\mhchem@cf@state{f}%
-              \fi\fi\fi%
+              \fi\fi\fi\fi%
             \else%
               \mhchem@cf@output@o{#1}%
             \fi\fi\fi%
@@ -829,7 +909,7 @@
       \mhchem@minispace% [3]
     }%
     \mhchem@mathortext@ii{% [5]
-      \mhchem@option@mathfont{#3}%
+      \mhchem@option@mathfont #3%
       }{\text{#3}}% [5]
     \ifthenelse{\equal{#4#5}{}}{}{%
       _{%
@@ -869,26 +949,150 @@
 %
 }
 
-\newcommand*{\mhchem@mathbox}[1]{\mathchoice%
+\newcommand*\mhchem@mathbox[2][]{%
+  \mathchoice%
+    {\mhchem@mathbox@ii{\displaystyle}{#1}{#2}}%
+    {\mhchem@mathbox@ii{\textstyle}{#1}{#2}}%
+    {\mhchem@mathbox@ii{\scriptstyle}{#1}{#2}}%
+    {\mhchem@mathbox@ii{\scriptscriptstyle}{#1}{#2}}}%
+\newcommand*\mhchem@mathbox@ii[3]{%    
+  \setlength{\dimen1}{\widthof{\ensuremath{#1#2}}}%
+  \setlength{\dimen2}{\widthof{\ensuremath{#1#3}}}%
+  \ifdim\dimen1<\dimen2%
+    \mhchem@mathbox@i{#3}%
+  \else%
+    \makebox[\dimen1]{\ensuremath{\displaystyle#3}}%
+  \fi}
+\newcommand*\mhchem@mathbox@i[1]{\mathchoice%
   {\mbox{\ensuremath{\displaystyle#1}}}%
   {\mbox{\ensuremath{\textstyle#1}}}%
   {\mbox{\ensuremath{\scriptstyle#1}}}%
   {\mbox{\ensuremath{\scriptscriptstyle#1}}}}
-
-\newcommand*{\mhchem@mathboxright}[2]{\mathchoice%
+  
+\newcommand*\mhchem@mathboxright[2]{\mathchoice%
   {\makebox[#1][r]{\ensuremath{\displaystyle#2}}}%
   {\makebox[#1][r]{\ensuremath{\textstyle#2}}}%
   {\makebox[#1][r]{\ensuremath{\scriptstyle#2}}}%
   {\makebox[#1][r]{\ensuremath{\scriptscriptstyle#2}}}}
 
-\def\mhchem@minispace{%
-  \setlength{\dimen2}{0pt-\widthof{${}^8_8$}+
+\newcommand*\mhchem@minispace{%
+  \setlength{\dimen2}{0pt-\widthof{${}^8_8$}+%
              \widthof{$\text{C}^8_8$}-\widthof{$\text{C}^{}_{}$}}% [3]
   \kern\dimen2%
               %
               %
 }
 
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%   Options   %%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\def\mhchem@option@version{0}
+\define@key{mhchem}{version}{\def\mhchem@option@version{#1}}
+
+\def\mhchem@option@mathfont{\mathrm}
+\def\mhchem@option@textfont{}
+\define@key{mhchem}{textfontcommand}{\def\mhchem@option@textfont{#1}}
+\define@key{mhchem}{textfontname}{\def\mhchem@option@textfont{\csname#1\endcsname}}
+\define@key{mhchem}{mathfontcommand}{\def\mhchem@option@mathfont{#1}}
+\define@key{mhchem}{mathfontname}{\def\mhchem@option@mathfont{\csname#1\endcsname}}
+\define@key{mhchem}{font}{%
+  \ifthenelse{\equal{sf}{#1}}{%
+    \def\mhchem@option@textfont{\sffamily}%
+    \def\mhchem@option@mathfont{\mathsf}%
+  }{\ifthenelse{\equal{}{#1}}{%
+    \def\mhchem@option@textfont{}%
+    \def\mhchem@option@mathfont{\mathrm}%
+  }{\PackageError{mhchem}{Font option `#1' unknown}}}%
+}
+
+\newlength\mhchem@option@minussidebearingleft
+\newlength\mhchem@option@minussidebearingright
+\setlength\mhchem@option@minussidebearingleft{0.06em}
+\setlength\mhchem@option@minussidebearingright{0.11em}
+\define@key{mhchem}{minus-sidebearing-left}{\setlength\mhchem@option@minussidebearingleft{#1}}
+\define@key{mhchem}{minus-sidebearing-right}{\setlength\mhchem@option@minussidebearingright{#1}}
+
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+%
+
+\def\mhchem@option@usenonsimultaneoussubsuperscripts{0}%
+\def\mhchem@option@alwaystextmode{0}%
+
+\mhchem@definearrows{font}
+\define@key{mhchem}{arrows}{%
+  \ifthenelse{\equal{pgf}{#1}}{%
+     \RequirePackage{pgf}% for finding the tikz package more easily
+     \RequirePackage{tikz}%
+  }{}%
+  \mhchem@definearrows{#1}%
+}
+
+%%% begin: standard keyval handling as in many other packages 
+\def\ProcessOptionsWithKV#1{%
+  \let\@tempc\relax%
+  \let\mhchem@tempa\@empty%
+  \@for\CurrentOption:=\@classoptionslist\do{%
+    \@ifundefined{KV@#1@\CurrentOption}%
+    {}%
+    {%
+      \edef\mhchem@tempa{\mhchem@tempa,\CurrentOption,}%
+      \@expandtwoargs\@removeelement\CurrentOption%
+        \@unusedoptionlist\@unusedoptionlist%
+    }%
+  }%
+  \edef\mhchem@tempa{%
+    \noexpand\setkeys{#1}{%
+      \mhchem@tempa\@ptionlist{\@currname.\@currext}%
+    }%
+  }%
+  \mhchem@tempa%
+  \let\CurrentOption\@empty%
+  \AtEndOfPackage{\let\@unprocessedoptions\relax}%
+}
+\ProcessOptionsWithKV{mhchem}\relax
+%%% end:
+
+\define@key{mhchem}{arrows}{\mhchem@definearrows{#1}}
+
+\newcommand*\mhchemoptions[1]{\setkeys{mhchem}{#1}}
+
+\ifnum0=\mhchem@option@version%
+  \PackageWarningNoLine{mhchem}{%
+    You did not specify a 'version' option for the mhchem\MessageBreak
+    package. This means you EITHER have an existing\MessageBreak
+    document and mhchem was updated to a newer version.\MessageBreak
+    Please check the mhchem manual in that case! OR, you\MessageBreak
+    are about to create a new document; in this case,\MessageBreak
+    please write \string\usepackage[version=3]{mhchem} in your preamble in\MessageBreak
+    order to use the most recent version of mhchem}%
+  \def\mhchem@option@version{1}%
+\else%
+\fi%
+
+
+
+
+
+
+
+
+
+
 %TODO: option for CrO_4{}^{2-} instead of CrO_4^{2-} - proper switch option [wordstyle] and documentation
 %TODO: option to use nicefrac
 %TODO: option for automatically using nicefrac im text mode
@@ -903,4 +1107,5 @@
 %TODO: always minimum length of arrows? override?
 %TODO: count0 und dimen@ eliminieren
 %
-%- ? option for labels on arrows in \scriptstyle? \textstyle?
\ No newline at end of file
+%
+%- option for centered bonds?
\ No newline at end of file