How to align all the molecules, the + sign and arrow at the same level?

Question

I use the chemfig package to draw molecules in a chemical reaction. However, I cannot align the molecules, the + sign and arrow at the base line. I have tried the \vphantom command, like in this question. But it does not work. I cannot use the \chemfig{} command to shift the molecules up or down. How could I handle this type of problem when using chemfig? Any tricks for new chemfig learners? Here's my output so far:

My code:

\documentclass{article}
\usepackage{chemfig}
\begin{document}
\setatomsep{3em}
\schemestart
\chemname{\chemfig{O=[:-90](-[:-150]H)-[:-30]OH}}{Formic acid} 
\+{2em, 2em, -3em} 
\vphantom{\+{,, -3em}}%
\chemname{\chemfig{CH_3OH}}{Methanol}
\arrow{<=>}
\chemname{\chemfig{O=[:-90](-[:-150]H)-[:-30]O-[:30]}}{Methyl formiate} 
\+{2em, 2em, -3em} 
\chemname{\chemfig{H_2O}}{Water}
\schemestop

\end{document}

Answer 1

chemfig always places the first atom of the molecule on the baseline, so if you write

\chemfig{O=[:-90](-[:-150]H)-[:-30]OH}

the oxygen will be on the baseline. To put the carbon on the baseline it has to be the first atom:

\chemfig{(-[:-150]H)(=[:90]O)-[:-30]OH}

In other words, you must start from the atom you want to be on the baseline and treat the others like branchings. The code is therefore

\documentclass{article}
\usepackage{chemfig}
\begin{document}
\setatomsep{3em}
\schemestart
\chemname{\chemfig{(-[:-150]H)(=[:90]O)-[:-30]OH}}{Formic acid}
\+
\chemname{\chemfig{CH_3OH}}{Methanol}
\arrow{<=>}
\chemname{\chemfig{(-[:-150]H)(=[:90]O)-[:-30]O-[:30]}}{Methyl formiate}
\+
\chemname{\chemfig{H_2O}}{Water}
\schemestop
\end{document}

Answer 2

Chemical formula are very difficult to do properly even with a good package like Chemfig. I would switch to a dedicated application like ChemDraw which has all of the functionality that you need for this problem as well all the extras for other more complex examples.

Sometimes one has to recognise that TeX/LaTeX cannot do it all ... more's the pity