The sulfate or sulphate (see spelling differences) ion is a polyatomic anion with the empirical formula SO 4 2− . Sulfate is the spelling recommended by IUPAC, but sulphate is used in British English. Salts, acid derivatives, and peroxides of sulfate are widely used in industry.Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.he sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries a negative two charge and is the conjugate base of the bisulfate (or hydrogen sulfate) ion, HSO 4 − , which is the conjugate base of H 2SO 4, sulfuric acid.