· H2O
It accepts one unnamed parameter that can give multiples:
{{Hydrate}}
{{Hydrate|5}}
{{Hydrate|2|nolink=yes}} gives · 2 H2O. However, if a link is not wanted, it is preferable to just lump the whole formula into {{chem2}}: {{chem2|CuSO4 * 5 H2O}} → CuSO4 · 5 H2O.
{{Hydrate|2|nolink=yes}}
{{chem2|CuSO4 * 5 H2O}}