It would be nice to have mhchem enabled, by adding

TeX: {
  extensions: ["mhchem.js"]

to the mathjax configuration. This would be useful to write chemical reactions.

  • 2
    $\begingroup$ related: siunitx LaTeX package?. $\endgroup$ Aug 5, 2017 at 10:50
  • 1
    $\begingroup$ FWIW, here's the related entries on Chemistry.SE. $\endgroup$
    – Qmechanic Mod
    Aug 5, 2017 at 10:59
  • $\begingroup$ The siunitx package is not part of the standard mathjax distro: enabling mhchem is just a one-line change. I can't even understand why this would cause a debate. Bandwidth? $\endgroup$
    – user154997
    Aug 5, 2017 at 11:31
  • $\begingroup$ For those of us who don't use mhchem it would be nice to have a link to a summary of what it is and how it works. Even the official LateX package documentation if the MathJax implementation adheres well. $\endgroup$ Aug 5, 2017 at 15:15
  • $\begingroup$ This may be the link I wanted: mhchem.github.io/MathJax-mhchem $\endgroup$ Aug 5, 2017 at 15:28
  • 8
    $\begingroup$ You can, of course, use \require{mhchem} in order to load mhchem as a one-off for the answer you are writing. E.g., $\require{mhchem} \ce{H20}$. You only need to use \require{mhchem} once on the page. $\endgroup$ Aug 7, 2017 at 0:39
  • $\begingroup$ @DavideCervone I was not aware of that. Nice there is a workaround. $\endgroup$
    – user154997
    Aug 7, 2017 at 0:45
  • $\begingroup$ @DavideCervone Hi. $\require{mhchem}$ loads the chemistry package, but $\require{physics}$ doesn't seem to load the physics package. For instance, $\require{physics}\dv[n]{f}{x}$ doesn't render. Any idea why? $\endgroup$
    – user199113
    Jan 20, 2019 at 11:41
  • 3
    $\begingroup$ For security reasons, \require{} only loads extensions that are in the core MathJax distribution. The mhchem extension is there because I did a version of it some time ago, but the physics extension is a third-party extension. So it can't be loaded in that way unless the site sets it up specifically to allow that, which is not the case here. $\endgroup$ Jan 20, 2019 at 16:10
  • $\begingroup$ @DavideCervone Gotcha. Thanks for the response! :) $\endgroup$
    – user199113
    Jan 20, 2019 at 16:57

1 Answer 1


I've marked this as since it recently came up again after three years of minimal activity and interest. If someone wants this feature, let's have a fresh thread about it.


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