What is the best way to have a 'detached but attracted' ion in chemfig? So I have a large molecule with a positive charge and want to position a negatively charged ion close by it.
According to my understanding, \charge{}{} or \Charge{}{} should be used. This works up until \charge{X}{Y^+}, but \charge{X^{-}}{Y^+} fails with some PGF error (roughly "can't divide 0 by 0"). My workaround is \charge{\ce{X-}}{Y}, but I don't like to use two separate packages.
Do you have any suggestions on how to better approach this?
My MWE is
\documentclass{article}
\usepackage{chemfig, mhchem}
\begin{document}
This is not quite minimal but shows what I intend:\\
\schemestart
\chemfig{[:90]-[@{op1,.5} ::-30]-[::-60](-[@{cl1,.5} ::60])-[::-60]C(=[::-60]O)-[::30]O-[@{op,.5} ::30]-[@{cl,.5} ::30]\charge{[extra sep=.4cm]130=\ce{X-}}{N^+}*5(=-N(-R)-=-)}
\polymerdelim[height = 5pt, indice = \!n', h align=false, delimiters={[]}]{op1}{cl1}
\polymerdelim[height = 5pt, indice = \!n, delimiters={[]}]{op}{cl}
\schemestop
\vspace{3cm}
This is actually minimal and works with package mhchem:\\
\vspace{1cm}
\charge{[extra sep=.4cm]130=\ce{X-}}{N^+}
\vspace{3cm}
This is what I want but doen't work
\vspace{1cm}
%\charge{[extra sep=.4cm]130=X^-}{N^+}
\end{document}
