The mhchem extensions implements the \ce and \pu chemical equation macros of the LaTeX mhchem package. See the mhchem home page for more information and documentation for mhchem.

For example

\ce{$A$ ->[\ce{+H2O}] $B$}
\ce{SO4^2- + Ba^2+ -> BaSO4 v}

This extension is loaded automatically when the autoload extension is used. To load the mhchem extension explicitly, add '[tex]/mhchem' to the load array of the loader block of your MathJax configuration, and add 'mhchem' to the packages array of the tex block.

window.MathJax = {
  loader: {load: ['[tex]/mhchem']},
  tex: {packages: {'[+]': ['mhchem']}}

Alternatively, use \require{mhchem} in a TeX expression to load it dynamically from within the math on the page, if the require extension is loaded.


The implementation of the mhchem extension was completely rewritten for MathJax by the author of the original LaTeX package. The older version was still available MathJax version 2.7, but it is no longer part of MathJax version 3. Only the newer version of mhchem is available.