On basic mercury salts
There exist plenty of basic salts. For example,

Copper produces a &quot;simple&quot; copper carbonate $\ce{CuCO3}$ as high $\ce{CO2}$ pressure. At lower pressures, the following basic copper carbonates are produced : $\ce{Cu3(CO3)2(OH)2}$ or $\ce{Cu2CO3(OH)2}$ (malachite), depending on the partial $\ce{CO2}$ pressure. Other copper salts produce basic copper salts like : $\ce{Cu2NO3(OH)3}$ , $\ce{Cu4(OH)6Cl2}$, $\ce{Cu4(OH)6SO4}$ .
Zinc produces the two following basic zinc carbonates, according to the chosen pH : $\ce{Zn5(OH)6(CO3)2}$ or $\ce{Zn2CO3(OH)2}$
Iron(III) produces also basic salts like $\ce{FeSO4(OH)}$ which is produced by air oxidation of iron(II) sulfate. Dilution of a ferric acetate solution produces a precipitate of basic acetate $\ce{Fe(CH3COO)(OH)2}$
Aluminum solutions are often hydrolyzed producing basic salts. In the case of acetate, it gives a precipitate of basic acetate $\ce{Al(CH3COO)(OH)2}$
Cobalt chloride solutions treated by cold NaOH solutions give a precipitate of basic chloride $\ce{CoClOH}$ When treated by carbonate solutions they produce a great variety of basic carbonates.
This list is not exhaustive.