How can I remove the space around chemfig figures?

Question

I want to create mesomeric formulas for Benzol, but for some reason, there is a lot of space around the benzol rings in the output... How can I fix this?

$
\left[
\chemfig[][scale=.7]{-[:-30]=^[:30]-[2]=^[: 150]-[:-150]=^[6]}
\leftrightarrow{\makebox[1cm]{}}
\chemfig[][scale=.7]{=^[:-30]-[:30]=^[2]-[: 150]=^[:-150]-[6]}
\right]
$

Answer 1

You get a better result with \schemestart...\schemestop:

\documentclass{article}
\usepackage{chemfig}

\begin{document}

$
\left[
\schemestart[][west]
\chemfig[][scale=.7]{-[:-30]=^[:30]-[2]=^[: 150]-[:-150]=^[6]}
\arrow{<->}
\chemfig[][scale=.7]{=^[:-30]-[:30]=^[2]-[: 150]=^[:-150]-[6]}
\schemestop
\right]
$

\end{document}

Answer 2

You do not need at all the math mode for this:

\documentclass{article}
\usepackage{chemfig}
\begin{document}
\schemestart
\chemleft[\subscheme{
\chemfig[][scale=.7]{-[:-30]=^[:30]-[2]=^[: 150]-[:-150]=^[6]}\arrow{<->}
\chemfig[][scale=.7]{=^[:-30]-[:30]=^[2]-[: 150]=^[:-150]-[6]}}
\chemright]
\schemestop
\end{document}