A persulfate (sometimes known as peroxysulfate or peroxodisulfate) is a compound containing the anionsSO2− 5 or S 2O2− 8. The anion SO2− 5 contains one peroxide group per sulfur center, whereas in S 2O2− 8, the peroxide group bridges the sulfur atoms. In both cases, sulfur adopts the normal tetrahedral geometry typical for the S(VI) oxidation state. These salts are strong oxidizers.