4. 大蒜素的形成

[[烯丙亚磺酸]]+[[烯丙硫醇（Allyl mercaptan）]]->[[大蒜素（Allicin）]]+{2}O$

$化学方程式：$

-

\usepackage{chemfig}
\begin{document}

\chemfig{
S(-[0.7,1]OH)
	(-[6,1,1,,->]O)
	(-[3.3,1]-[4.7,1]=[3.3,1])
}
+
\chemfig{
SH
	(-[3.3,1]-[4.7,1]=[3.3,1])
}

\begin{tikzpicture} 
\draw [->] (0,0) to node[above] {} (2,0); % 水平箭头 
\end{tikzpicture}

\chemfig{
S
	(-[0.7,1]S-[7.3,1]-[0.7,1]=[7.3,1])
	(-[6,1,1,,->]O)
	(-[3.3,1]-[4.7,1]=[3.3,1])
}
+
{2}O$

\end{document}