How to make mhchem work with \bgroup and \egroup satements?

Question

I am trying to create a table in which a column consists entirely of chemical formulae. I would like to use the array package to automatically insert the \ce{...} command, taking the cell's content as argument.

I understand from “\bgroup and \egroup? ” that \bgroup and \egroup only work for replacements for low level commands like \textbf. Unfortunately I do not understand how to use the realboxes package provided there to make it work. I cannot assess if it is appropriate for that task in the first place.

Here is a minimal not working example of what I am trying to do:

\documentclass{article}
\usepackage[version=4]{mhchem}
\usepackage{array}
\begin{document}
  \begin{tabular}{>{\textbf\bgroup}l<{\egroup}%
                  >{\ce\bgroup}l<{\egroup}}\hline
    R1 & -C6H5 \\
    R2 & -C6H4F \\\hline
  \end{tabular}
\end{document}

The answer you cite doesn't say that \bgroup and \egroup work with \textbf. They just seem to, but it's by pure chance. — egreg, Jun 28 '16 at 09:03
@egreg Thank you for the clarification. I thought \textbf is a low level command. — Martin - マーチン, Jun 28 '16 at 09:05

yo' · Accepted Answer · 2016-06-28T09:00:33.317

The package collcell is your friend for this:

\documentclass{article}
\usepackage[version=4]{mhchem}
\usepackage{array,booktabs,collcell}

\begin{document}
  \begin{tabular}{>{\bfseries}l
                  >{\collectcell\ce}l<{\endcollectcell}}\toprule
    R1 & -C6H5 \\
    R2 & -C6H4F \\\bottomrule
  \end{tabular}
\end{document}

Note that I also used booktabs for the table rules. Last but not least, you don't need \textbf, you can use \bfseries which does not take an argument.

How to make mhchem work with \bgroup and \egroup satements?

1 Answers1