The binary diagram water + barium chloride

As part of a larger work on the production of solid metal by FFC electro-deoxidation in liquid salts, some candidate raw materials (i.e. hydrated salts) were studied with respect to thermal equilibria, in particular de-hydration. This paper presents the first complete review and critical assessment of the thermal equilibria of the hydrates of BaCl2. A consistent set of optimised equations is presented for the water pressure within the bi-phase regions of the binary system H2O–BaCl2, along with a complete update of the corresponding T–X phase diagram. Finally, it is suggested that the hemi-hydrate (BaCl2·1/2 H2O) is only barely stable, and that the formation of hemi-hydrate (from BaCl2·H2O + BaCl2) is driven by entropy only. An important correction to Holmes (J. Chem. Thermodynamics 28 (1996) 1325; J. Chem. Thermodynamics 29 (1997) 1363) is pointed out. To cite this article: J. Fenstad, D.J. Fray, C. R. Chimie 9 (2006).