Chemfig: bond alignment in sigma complexes

Question

I want to make a sigma complex with chemfig, but the alkene is anchored to the south-west corner, and not the center. How can I fix this?

MWE

\documentclass{article}
\usepackage{chemfig}

\definesubmol{A}{CO -[2] Cr (>:[:20]CO) (>[:-20]CO) (>:[:160]OC) (>[:-160]OC)}
\begin{document}
\chemfig{!{A} -[:90] =}
\end{document}

This image shows the undesirable behavior:

Answer 1

You could draw two double bonds with a half of default length. The code below show such approach (with different color to help the understand).

\documentclass{article}
\usepackage{chemfig}
\definesubmol{A}{CO -[2] Cr (>:[:20]CO) (>[:-20]CO) (>:[:160]OC) (>[:-160]OC)}
\begin{document}
\chemfig{!{A}-[:90,,,,dashed](=[::-90,0.5,,,red])(=[::90,0.5,,,blue])}
\end{document}