Barium Chlorate, Ba(ClO₃)₂

Barium Chlorate, Ba(ClO₃)₂, is formed by the neutralisation of barium hydroxide or carbonate with chloric acid. It may also be precipitated by the action of ammonium chlorate, or aluminium chlorate, on barium carbonate, preferably in boiling alcohol. By the action of chlorine at 80° C. on barium hydroxide solution, or on barium carbonate suspended in water, chlorate mixed with chloride is obtained. The latter can, for the most part, be removed by recrystallisation.

From solution the monohydrate separates out in colourless, monoclinic crystals. The chlorates of the alkaline earths exhibit crystallo- luminescence on crystallising out. The density is 3.179, and the specific heat 0.157. The salt loses its water of crystallisation at 180° C., and slowly decomposes at 300°-310° C., with the formation of perchlorate and chloride and the loss of oxygen. The rate of decomposition increases with rise of temperature, and the reaction continues until about 10 per cent, of oxygen has been lost.

When mixed with a reducing agent, barium chlorate readily explodes. It reacts with iodine, forming iodic and chloric acids and barium iodide. With sulphurous acid at 60° C. barium sulphate and chlorine monoxide are obtained. Sulphuric acid decomposes it with the production of light. The heat of solution of the anhydrous salt is -6.7 Cal. The heat of solution of the monohydrate is -11.24 Cal., and, therefore, the heat of hydration is 4.54 Cal.

The following values have been found for the solubility: -

Temperature, °C	-2.749±0.004 cryohydric point	0	10	20	30	40	50	60	70	80	90	99.1	105° boiling-point
Grams anhydrous salt per 100 grams solution	15.28	16.9	21.23	25.26	29.43	33.16	36.69	40.05	43.04	45.90	48.47	51.17	52.67

The vapour pressures and refractive indices of barium chlorate solutions have been determined.

The salt is only slightly soluble in alcohol.

Barium chlorate is used in pyrotechnics for the production of green fire.