In chemistry, peroxycarbonate (sometimes peroxocarbonate, IUPAC name: oxocarbonate or oxidocarbonate) or percarbonate is a divalent anion with formula CO2−4.

It is an oxocarbon anion that consists solely of carbon and oxygen.

The peroxycarbonate anion is formed, together with peroxydicarbonate C2O2−6, at the negative electrode during electrolysis of molten lithium carbonate.

The peroxycarbonate anion has been proposed as an intermediate to explain the catalytic effect of CO2 on the oxidation of organic compounds by O2.

[6] The potassium and rubidium salts of the monovalent hydrogenperoxycarbonate anion (aka.