At right, the vertical arrow from ethylene to M
is a coordination bond. Is it possible to centrally align the two molecules (ethylene and the solid catalyst surface), aligning their centers with the coordination bond arrow?
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{arrows.meta}
\usepackage{chemfig}
\usetikzlibrary{shapes,positioning,intersections,quotes}
\setchemfig{%
arrow offset=9pt,
arrow coeff=0.7,
+ sep left=0.3em,
+ sep right=0.3em,
atom sep=1.5em,
fixed length=true
}
\begin{document}
\schemestart
\chemfig{C(-[3]H)(-[5]H)=C(-[1]H)-[7]H}
\arrow{0}[,0] \+
\chemfig{ M (-[0]M{\sim}) (-[4]{\sim}M) }
\arrow
\subscheme{
\chemfig{H_2C=[@{bond}]CH_2}
\arrow{0}[-90,.23]
\chemfig{ M (-[0]M{\sim}) (-[4]{\sim}M) }
\chemmove{
\node[below=3px of bond] (double_bond) {};
\node[below=19px of bond] (solid_surface) {};
\draw[-stealth](double_bond)--(solid_surface);
}
}
\schemestop
\end{document}