Barium Perchlorate, Ba(ClO₄)₂

Barium Perchlorate, Ba(ClO₄)₂, may be obtained by the action of perchloric acid on barium hydroxide or carbonate, or by the interaction of zinc perchlorate with barium hydroxide. It is also formed by heating the chlorate.

It forms hexagonal prisms containing 3 molecules of water. It is not hygroscopic if free from perchloric acid, and is soluble in water and alcohol. It loses 2 molecules of water over concentrated sulphuric acid at room temperature, becomes anhydrous at 100° C., and at 400°-460° C. it decomposes. The heat of solution of the anhydrous salt is -1.8 Cal., and of the trihydrate -9.4 Cal. Therefore the heat of hydration is 7.6 Cal. A dihydrate and a monohydrate have also been mentioned.

The anhydrous salt is said to exist in two forms, the transition point being 284° C.