Barium Permanganate, Ba(MnO₄)₂

Barium Permanganate, Ba(MnO₄)₂, is obtained in fine orthorhombic octahedra, which are deliquescent and almost black with violet reflections, by saturating a solution of potassium permanganate with hydrofluosilicic acid, treating with a suspension of barium hydroxide, and crystallising. It may also be prepared by the action of barium nitrate and barium hydroxide on potassium permanganate and subsequent treatment with carbon dioxide. Other methods are unsatisfactory.