Equilibrium phases in the BeSO₄-H₂O system

Abstract

The equilibrium phases of the BeSO₄-H₂O system were studied by vapour hydration of BeSO₄ and equilibration of thermally produced mixtures. Tetra-, di-, and mono-hydrate are the stable hydrates with no solid solution regions between them. X-ray and infrared spectra are presented for these hydrates and a provisional phase diagram drawn.    Reversible transitions of BeS0₄ were found at 588° and 639°, the latter showing a hysteresis splitting of 4° on cooling. Transition heats of 1.2 ± 0.1 and 0.5 ± 0.1 kcal/mole respectively were found by differential thermal analysis.