# colored coefficients using package chemformula

For a beamer presentation I want to apply the nice chemformula package. I now wish to have only the coefficients colored individually, for example marking the first coefficient in blue:

\ch{\color{blue}106 CO2 + 122 H2O + 16 HNO3 + H3PO4 -> (CH2O)106 + (NH3)16(H3PO4) + 138 O2}


As soon as I include the \color command (as explained in the chemformula manual), the coefficient becomes a subscript. I also tried

\ch{ \textcolor{blue}{106} CO2 + 122 H2O + ...,


which generates the same result. The equation looks fine when I omit any attempt coloring the coefficients. What am I missing here? I assume that there is a very simple solution to this problem. Any advice is much appreciated, thanks. Markus

A stoichiometric factor may only contain numbers and the signs . ,_ /().

As alternative you might prevent chemformula from parsing the input, for example using \ch{"⟨escaped text⟩"}

Compounds are more straightforward. (Third formula)

\documentclass[11pt]{beamer}

\usepackage{lmodern}
\usetheme{default}

\usepackage{chemformula}
\begin{document}
\begin{frame}
\frametitle{}
\ch{106 CO2 + 122 H2O + 16 HNO3 + H3PO4 -> (CH2O)106 + (NH3)16(H3PO4) + 138 O2}\bigskip

\ch{"\color{blue}" 106}\ch{CO2 + 122 H2O + 16 HNO3 + H3PO4 -> (CH2O)106 + (NH3)16(H3PO4) + 138 O2}\bigskip

\ch{106 \color{red}CO2 + 122 H2O + 16 HNO3 + H3PO4 -> (CH2O)106 + (NH3)16(H3PO4) + 138 O2}

\end{frame}
\end{document}