Calcium Manganites

Crystallised manganites, of composition varying with the temperature, can be obtained by heating together calcium chloride, calcium oxide, and manganese chloride. At a bright red heat MnO₂.2CaO is formed, and at lower temperatures 2MnO₂.CaO, 3MnO₂.CaO, and CaO.MnO₂. Potassium permanganate with calcium chloride gives a pentamanganite, 5MnO₂.CaO.

By the action of a manganese salt on excess of calcium hypochlorite brownish precipitates of variable composition are obtained. They constitute the Weldon mud produced in the regeneration of manganese dioxide in the Weldon chlorine process.