How do I write chemical reaction-diffusion formula in LaTex?

How can I write the following chemical reaction-diffusion formula (see figure) in LaTex?

My main objective is, how do I produce the two way arrows with single letters above and below? • Or package mathtools with A \xleftrightharpoons[k_{-1}]{k_{1}} G for instance – BambOo Aug 14 '18 at 13:27
• The comment from clemens worked! – Brendan Darrer Aug 14 '18 at 13:50
• I used: \usepackage[version=4]{mhchem} in TeXstudio & ----> $$\ce{A <=>[{k_1}][{k_{-1}}] G}\\$$ – Brendan Darrer Aug 14 '18 at 14:23
• You should not use , but otherwise it's perfectly fine to self-answer a question if you found a solution for yourself. – TeXnician Aug 14 '18 at 15:06

Here are two suggestions, the first using chemformula (via chemmacros), the second using mhchem.

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

\begin{subequations}
\begin{equation}
\ch{A <=>[ $k_1$ ][ $k_{-1}$ ] K}
\end{equation}
\begin{equation}
\ch{G <=>[ $k_2$ ][ $k_{-2}$ ] X}
\end{equation}
\begin{equation}
\ch{B + X <=>[ $k_3$ ][ $k_{-3}$ ] Y + Z}
\end{equation}
\begin{equation}
\ch{2 X + Y <=>[ $k_4$ ][ $k_{-4}$ ] 3 X}
\end{equation}
\begin{equation}
\ch{X <=>[ $k_1$ ][ $k_{-1}$ ] \chemOmega}
\end{equation}
\end{subequations}

\end{document} \documentclass{article}
\usepackage[version=4]{mhchem}
\begin{document}

\begin{subequations}
\begin{equation}
\ce{A <=>[$k_1$][$k_{-1}$] K}
\end{equation}
\begin{equation}
\ce{G <=>[$k_2$][$k_{-2}$] X}
\end{equation}
\begin{equation}
\ce{B + X <=>[$k_3$][$k_{-3}$] Y + Z}
\end{equation}
\begin{equation}
\ce{2X + Y <=>[$k_4$][$k_{-4}$] 3X}
\end{equation}
\begin{equation}
\ce{X <=>[$k_1$][$k_{-1}$] \Omega}
\end{equation}
\end{subequations}

\end{document} 