[Tex/LaTex] Setting up a redox reaction using chemmacros

Question

I've been trying to set up this redox reaction for quite some time now, having searched the web for answers and being unable to find them I resorted to ask in here. I'm looking for a way to modify the code below so that hydrazine molecule can stay as a molecule but get the right amount of atoms, currently I'm only able to append a number to the last atom in the molecule, but not on the nitrogen atom, does anyone have a solution or workaround for this?

\documentclass[a4paper,danish,11pt,final]{article}

\usepackage{chemmacros}
\begin{document}

\vspace{7mm}
\ch{
"\OX{o1,\ox{0,N}\ox{0,Cl}}" {}2 + "\OX{r1,\ox{0,Cl}}" {}3
->
"\OX{o2,\ox{+1,Na}}" {}+ + 2 "\OX{r2,\ox{-1,Cl}}" {}-
}
\redox(o1,o2){\small OX: $- 2\el$}
\redox(r1,r2)[][-1]{\small RED: $+ 2\el$}
\vspace{7mm}

\end{document}

Ends up looking like this:

I wanna append the 2 to the Nitrogen instead of the Chlorine atom. We're looking at the first molecule here, I wanted to get that one setup before writing the rest out, seeing how the first one didn't go too well..

Answer 1

You can use \chcpd inside \OX, \ox (and even \ch) for typesetting compounds. \chcpd is described in the manual for chemformula. In this case you can use it for adding the subscripts. It looks a bit clumsy but works…

\documentclass{article}
\usepackage{chemmacros}
\begin{document}

\ch{
"\OX{o1,\ox{1,N}\chcpd{2}\ox{-1,Cl}\chcpd{2}}" + "\OX{r1,\ox{0,Cl}}" {}3
->
"\OX{o2,\ox{+1,Na}}" {}+ + 2 "\OX{r2,\ox{-1,Cl}}" {}-
}
\redox(o1,o2){\small OX: $- 2\el$}
\redox(r1,r2)[][-1]{\small RED: $+ 2\el$}

\end{document}