Barium Borates

Guertler studied the freezing-point curves of mixtures of barium oxide and boric anhydride and came to the conclusion that the following chemical individuals exist: the orthoborate, 3BaO.B₂O₃, the pyroborate, 2BaO.B₂O₃, in a crystalline marble-like mass, the metaborate, BaO.B₂O₃, crystallising in flat prisms, and the biborate, BaO.2B₂O₃, which does not readily crystallise.

Precipitates of varying composition are obtained by mixing solutions of borax and a soluble barium salt, or by the interaction of barium hydroxide with boric anhydride. They are soluble in solutions of ammonia salts, and the action of carbon dioxide has also been studied. The system BaO: B₂O₃: H₂O has been investigated by Sborgi, who confirmed the existence of the following compounds: BaO.B₂O₃.4H₂O, 2BaO.3B₂O₃.6H₂O, and BaO.3B₂O₃.7H₂O.