Polonium(IV) sulfate is an inorganic compound 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)[1] and sulfuric acid.[2] Polonium(IV) sulfate can be reduced to [3] by hydroxylamine in acidic solutions; it decomposes to polonium dioxide at 550 °C. It is radioactive and produces gases as it decays.