Beryllium Pyrosulfate

Description

Beryllium pyrosulfate is not stable in aqueous solution and so must be prepared via a solid-state reaction. It would have the molecular formula of BeS₂O₇ and the molecular weight of 185.1401 g/mol. It could be prepared by the reaction involving “fuming” sulfuric acid (oleum) with beryllium sulfate:
[Be(OH)]2SO4+(H2SO4)n ? 2BeS2O7+(n+2) H2O
The [Be(OH)]₂SO₄ salt is added to the oleum and allowed to dissolve in an excess of acid. The acid is heated to 150–175°C to drive off the water. This is an equivalent of using H₂S₂O₇. The solution is allowed to equilibrate and crystals of the anhydrous salt appear. These are separated and allowed to dry. Beryllium disulfate is stable and may be heated to a red heat before it begins to decompose to the sulfate and SO₃.