Barium selenate

Barium selenate is an inorganic compound with the chemical formula BaSeO4. It is isomorphous with barium sulfate, but its solubility is 18 times that of barium sulfate, and its thermal stability is worse than that of barium sulfate.

Preparation
Barium selenate can be obtained from the reaction of any soluble barium salt and sodium selenate:


 * BaCl2 + Na2SeO4 → BaSeO4↓ + 2 NaCl

Properties
Barium selenate is a white solid that is slightly soluble in water. When heated above 425 °C, the compound decomposes. Another barium selenate, barium diselenate, BaSe2O7, is also known. It has an orthorhombic baryte-type crystal structure with the space group Pnma (space group no. 62) (a = 8.993 Å, b = 5.675 Å, c = 7.349 Å).

Uses
Barium selenate has been used as a "slow release" source of selenium for grazing animal feed crops and was intended to ensure selenium supply to grazing animals. In Switzerland and the EU, direct use as a feed additive is prohibited. Barium selenide can be obtained by reducing barium selenate in a hydrogen stream:


 * BaSeO4 + 4 H2 → BaSe + 4 H2O