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%%  Ein Beispiel der DANTE-Edition
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%%  2. Auflage
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%%  Beispiel 15-05-6 auf Seite 816.
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%%  Copyright (C) 2016 Herbert Voss
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%%  It 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.
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%%  See http://www.latex-project.org/lppl.txt for details.
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{352.81416pt}
\parindent=0pt
%StartShownPreambleCommands
\usepackage{chemmacros,chemformula}
\usechemmodule{redox,reactions}
%StopShownPreambleCommands
\begin{document}
\chemsetup[chemformula]{compound-sep=0pt}
\begin{reaction*}
(1/5) K "\ox*{7,Mn}" O4 + (8/5) HCl ==
(1/5) "\ox*{2,Mn}" Cl2 + (1/2) Cl2 + (1/5) KCl + (4/5) H2O
\end{reaction*}
\end{document}