\usemodule[chemic]
\chemical{HSO_4^{-}}
</context>
* It can also be used to typeset chemical ''reactions''
<texcode>
\usemodule[chemic]
\startformula
\chemical{2H_2,+,0_2,->,2H_20}
\stopformula
</texcode>
<context>
\usemodule[chemic]
\startformula
\chemical{2H_2,+,0_2,->,2H_20}
\stopformula
</context>