# redox reactions with arrows and enumeration using chemmacros

I'm using the chemmacros package and I'd like to have a counter on the left of the following equation:

I've tried using the \begin{reactions} command but I only get this:

I can't figure out how to get the first equation (with arrows) with the numeration from the last one.

Here's my code for the last equation:

\begin{reactions}
H2O + "\OX{o1,\ox*{+4,S}\ox*{-2,O2}}" \gas{} + "\OX{r1,\ox*{0,I2}}" \aq{} ^
->
H2 "\OX{o2,\ox*{+6,S}\ox*{-2,O4}}" \aq{} + 2 "\OX{r2,\ox*{+1,H}\ox*{-1,I}}" \aq{}
\end{reactions}
\redox(o1,o2)[->]{\small Oxidation: $- 2\el$}
\redox(r1,r2)[->][-1]{\small Reduktion: $+ 2\el$}


Replacing \begin{reactions} with \ch{ and \end{reactions} with } will give equation 1 again. Putting \end{reactions} at the very bottom of the code provided will give a bunch of errors. I'd really appreciate any help.

P.S. Don't mind the validity of the equation.

• As long as the numbering is continued orderly reaction would suffice. – batatafrita Oct 19 '16 at 17:14

Place the \redox... calls inside the reaction (or reactions) environment but also escape them:

\documentclass{article}

\usepackage{chemmacros}
\usechemmodule{redox,reactions}

\begin{document}

\begin{reaction}
H2O + "\OX{o1,\ox*{+4,S}\ox*{-2,O2}}" \gas{} + "\OX{r1,\ox*{0,I2}}" \aq{} ^
->
H2 "\OX{o2,\ox*{+6,S}\ox*{-2,O4}}" \aq{} + 2 "\OX{r2,\ox*{+1,H}\ox*{-1,I}}" \aq{}
"\redox(o1,o2)[->]{\small Oxidation: $- 2\el$}"
"\redox(r1,r2)[->][-1]{\small Reduktion: $+ 2\el$}"
\end{reaction}

\end{document}