Hafnium(IV) sulfate is describes the inorganic chemical compounds with the formula Hf(SO4)2·nH2O, where n can range from 0 to 7.

[1] Anhydrous hafnium(IV) sulfate consists of a polymeric network of sulfate-bridged hafnium atoms.

[1] Hafnium(IV) sulfate tetrahydrate is isomorphous with zirconium(IV) sulfate tetrahydrate and consists of repeated sheets of Hf(SO4)2(H2O)4, where the sulfate ligands are bidentate.

[1] The tetrahydrate is produced by the reaction of hafnium metal or hafnium(IV) oxide with concentrated sulfuric acid followed by evaporation of the solution:[1] The anhydrous form can be produced by heating the tetrahydrate to 350 °C.

[2] Various hydrolyzed derivatives of hafnium(IV) oxide, such as [Hf18O10(OH)26(SO4)12.7(H2O)20]Cl0.6·nH2O are known.