\documentclass{article}
\usepackage{chemfig}
\usepackage{chemmacros}
\chemsetup{modules=all}
\begin{document}
\setchemfig{lewis sep=0.6ex}
\chemfig{
(-[2,0.6,,,draw=none]{\orbital[scale=1.2, half, color=gray!50]{p}})
(
-[,0,,,draw=none]@{x1}{\lewis[lewis style=red,lewis sep=14pt]{2:,Sn}}
(-[:-30]{\lewis{0:2:6:,Cl}})
-[:-150]{\lewis{2:4:6:,Cl}}
)
}
\chemmove{
\draw[latex-latex, red]
($(x1)+(210:1.6em)$) arc[start angle=210, end angle=330, radius=1.6em]
node[midway, yshift=-6pt] {\color{blue}\footnotesize \(\approx 120^\circ\)};
}
\end{document}