Polonium(IV) sulfate is an inorganic compound, a salt of polonium and the sulfate anion with the chemical formula of . As anhydrous, it forms dark purple crystalline solid, and as a hydrate, it forms colourless or white crystals, and is soluble in water. It can be obtained by the reaction of polonium tetrachloride (or hydrated polonium dioxide) and sulfuric acid. Polonium(IV) sulfate can be reduced to by hydroxylamine in acidic solutions; it decomposes to polonium dioxide at 550 ðC. It is radioactive and produces gases as it decays.