# mhchem extension This extension adds to KaTeX the `\ce` and `\pu` functions from the [mhchem](https://mhchem.github.io/MathJax-mhchem/) package. ### Usage This extension isn't part of core KaTeX, so the script should be separately included. Write the following line into the HTML page's ``. Place it *after* the line that calls `katex.js`. ```html ``` ### Syntax See the [mhchem Manual](https://mhchem.github.io/MathJax-mhchem/) for a full explanation of the input syntax, with working examples. The manual also includes a demonstration box. ### Browser Support This extension has been tested on Chrome, Firefox, Opera, and Edge.