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%%  Ein Beispiel der DANTE-Edition
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%%  2. Auflage
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%%  Beispiel 15-05-4 auf Seite 815.
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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
\usepackage[scaled=0.85]{beramono}
%StartShownPreambleCommands
\usepackage{chemformula,mhchem}
%StopShownPreambleCommands
\begin{document}
Paket \texttt{chemformula}: \ch{H2SO4} \ch{PO4^3-} \par
Paket \texttt{mhchem}:      \ce{H2SO4} \ce{PO4^3-}
\end{document}