How to represent a chemical reaction network

Question

What is the simplest way to represent a reaction network using LaTeX? An example of a reaction network is shown below:

Answer 1

chemfig can do this:

\documentclass{article}
\usepackage{chemfig}
\begin{document}
\schemestart
    \subscheme{B + E}
    \arrow(be--ac)[135]
    \subscheme{A + C}
    \arrow[90]
    \chemfig{A}
    \arrow{<=>}
    \chemfig{B}
    \arrow(@be--d){<=>}[45]
    \chemfig{D}
    \arrow(@ac--@d){<=>}
\schemestop
\end{document}