Beryllium sulfate
Beryllium sulfate normally encountered as the tetrahydrate, BeSO4·4H2O is a white crystalline solid. It was first isolated in 1815 by Jons Jakob Berzelius.
Beryllium sulfate may be prepared by treating an aqueous solution of any beryllium salt with sulfuric acid, followed by evaporation of the solution and crystallization. The hydrated product may be converted to anhydrous salt by heating at 400 °C. The tetrahydrate contains a tetrahedral Be(OH2)4 unit and sulfate anions. The small size of the Be cation determines the number of water molecules that can be coordinated. This contrasts with the analogous magnesium salt, MgSO4·6H2O which contains an octahedral Mg(OH2)6 unit.