Following proper typesetting standards is absolutely essential on a technical site like Quantum Computing Stack Exchange.
I came across this question on the main site: What kinds of ions do trapped ion quantum computers use? whose answer needed at least a minimal usage of chemical expressions, however initially it was not properly typeset.
The LaTeX package mhchem is not activated here, by default. However, you can load it yourself, by using the command \require{\mhchem} (you need to use it only once on a page).
Example: \require{\mhchem}\ce{H2O} generates $\require{\mhchem}\ce{H2O}$.
Courtesy: @DavidCervone on Physics SE
For further guidance on how to format chemical expressions check this Chemistry SE post: How can I format math/chemistry expressions here?
