\schemestart[][west]
\chemfig{-[1]-[-1]-[1]@{el2}-[@{ls1}-1]@{el1}\charge{45=\|,-45=\|,-135=\|}{Br}} \arrow{0}[,0]\+ \chemfig{@{nu2}\charge{0=\|,90=\|,180=\|,-90=\|,45:4pt=$\scriptstyle\ominus$}{I}}
\arrow{<=>}
\chemfig{-[1]-[-1]-[1]-[-1]\charge{-45=\|,45=\|,-135=\|}{I}} \arrow{0}[,0]\+ \chemfig{\charge{0=\|,90=\|,180=\|,-90=\|,45:4pt=$\scriptstyle\ominus$}{Br}}
\schemestop
\chemmove{
	\draw[shorten <=3pt,shorten >=4pt]
        (nu2)..controls +(90:7mm) and +(45:7mm)..(el2);
    \draw[shorten <=3pt,shorten >=4pt]
		(ls1)..controls +(-135:5mm) and +(180:5mm)..(el1);
	}