$\underset{(Z\And E)}{\mathop{\begin{matrix}
^{Br} \\
_{I} \\
\end{matrix}\begin{matrix}
\text{ }\!\!\backslash\!\!\text{ } \\
/ \\
\end{matrix}C=C\begin{matrix}
/ \\
\text{ }\!\!\backslash\!\!\text{ } \\
\end{matrix}_{F}^{Cl}}}\,$ $\underset{(Z\And E)}{\mathop{\begin{matrix}
^{Br} \\
_{Cl} \\
\end{matrix}\begin{matrix}
\text{ }\!\!\backslash\!\!\text{ } \\
/ \\
\end{matrix}C=C\begin{matrix}
/ \\
\text{ }\!\!\backslash\!\!\text{ } \\
\end{matrix}_{I}^{F}}}\,$ $\underset{(Z\And E)}{\mathop{\begin{matrix}
^{Cl} \\
_{I} \\
\end{matrix}\begin{matrix}
\text{ }\!\!\backslash\!\!\text{ } \\
/ \\
\end{matrix}C=C\begin{matrix}
/ \\
\text{ }\!\!\backslash\!\!\text{ } \\
\end{matrix}_{F}^{Br}}}\,$
$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,CHO} \\
{|\,\,\,} \\
{H - C - OH} \\
{|\,\,\,\,} \\
{\,\,\,\,\,\,\,\,\,C{H_2}OH}
\end{array}$
$\begin{array}{*{20}{c}}
{^{C{H_3}}} \\
{_H}
\end{array}\begin{array}{*{20}{c}}
{{\text{ }}\backslash {\text{ }}} \\
/
\end{array}\mathop C\limits^{} {\mkern 1mu} = \mathop C\limits^{} {\mkern 1mu} \begin{array}{*{20}{c}}
/ \\
{{\text{ }}\backslash {\text{ }}}
\end{array}_{\mathop C\limits^{} {\kern 1pt} \equiv \mathop C\limits^{} {\kern 1pt} - \mathop C\limits^{} {\kern 1pt} {H_2}\mathop C\limits^{} {\kern 1pt} {H_3}}^H{\mkern 1mu} $