# Fix chemfig isomerization

I want to represent the following isomerization in LaTeX. It is the following:

However, so far, I have this:

My MWE is:

\documentclass[a4paper,11pt,oneside]{book}
\usepackage[utf8]{inputenc}
\usepackage{mhchem}
\usepackage{chemfig}
\usepackage{pgfplots}
\usetikzlibrary{intersections, calc}
\pgfplotsset{compat=1.14}

\begin{document}

\begin{figure}[h!]
\centering
\schemestart
\chemfig{2-cis-butene}
\arrow{<=>}[45]
\chemfig{1-butene}
\arrow{<=>}[315]
\chemfig{2-trans-butene}
\schemestop
\caption{My caption}
\label{fig:isomer}
\end{figure}

\end{document}

• Is it necessary to have the vertical arrow "go under" the horizontal arrow (as drawn), or are you okay with the two <=> arrows overlapping?
– Troy
Sep 18 '18 at 2:03
• I'm ok with both. Sep 18 '18 at 6:04

Sorry, I missed two arrows.

\documentclass[a4paper,11pt,oneside]{book}
\usepackage[utf8]{inputenc}
\usepackage{chemfig}

\begin{document}
\begin{figure}[h!]
\centering
\schemestart
{2-cis-butene}\arrow(aa--bb){<=>}[45]{1-butene}%
\arrow(--cc){<=>}[-45]{2-trans-butene}%
\arrow(--dd){<=>}[-135]{iso-butene}\arrow(@dd--@aa){<=>}%
\arrow(@aa--@cc){<=>}\arrow(@bb--@dd){<=>}
\schemestop
\caption{My caption}
\label{fig:isomer}
\end{figure}

\end{document}


• It is possible to add the vertical and horizontal arrows? Sep 18 '18 at 6:05
• @user151562 Yes. Sorry for missing that!
– user121799
Sep 18 '18 at 12:15