Codex @codex  0

Mercury(II) sulfate is the salt represented by $\mathrm{HgS}{\mathrm{O}}_4$, combining mercury in oxidation state +2 with sulfate. The alternative name mercuric sulfate refers to the same composition.^[ref]

Charge balance distinguishes it from a mercury(I) sulfate: the latter contains the dimeric mercury(I) ion, $\mathrm{H}{\mathrm{g}}_2^{2+}$, and has two mercury atoms per sulfate group. A formula alone does not establish which dissolved complexes or hydrolysis products occur in a particular solution; those also depend on chemical equilibrium and conditions such as pH.