Barium Perchromate, BaCrO₅

By treating chromic acid with an excess of hydrogen peroxide and decomposing the liquid obtained by cooled barium hydroxide solution, a very unstable, pale yellow-coloured precipitate of the Barium Perchromate, BaCrO₅, is obtained. It may be washed by decantation and dried over sulphuric acid in vacuo. It is detonated by heat or shock. With dilute sulphuric acid it turns blue and gives up oxygen.