Hazard and Precautionary Statements (GHS)

Barium Arsenites Chemical Properties,Usage,Production

Description

Tribasic barium arsenite, Ba3(AsO3)2, has been prepared by the addition of potassium orthoarsenite to an aqueous solution of barium chloride and drying the precipitate at 100 C in a current of hydrogen gas. The pH needs to at least 13.5. It is obtained as a white amorphous powder, readily soluble in hot water and in dilute acids. When heated rapidly to about 730 °C in an inert atmosphere, it decomposed into arsenic and the arsenate. This is a double oxidation–reduction reaction in which part of the tribasic arsenite is oxidized and part reduced:
4Ba3（AsO3）2 + heat ? 12BaO + 4As2O3 + 4As
4As2O302As2O5 + 4As + 2O2
4Ba3（AsO3）2 + heat ? 12BaO + 2As2O5 + 8As + 2O2
Slow heating below 300 °C causes loss of arsenious oxide if heated in hydrogen or arsenic pentoxide if heated in air:
Ba3(AsO3)2 + Heat (H2) ? 3BaO + As2O3