Barium Azide, BaN(₃)₂

Barium Azide, Ba(N₃)₂, may be prepared by the action of hydrazoic acid on barium hydroxide, or of a boiling solution of ammonium azide on the freshly precipitated hydroxide. There is, apparently, always too little barium present in the salt prepared by the second method. It forms triclinic crystals containing 1 molecule of water, which is removed by drying over sulphuric acid.

Barium azide is not hygroscopic, and it is less soluble in water than the corresponding calcium and strontium salts, 100 parts of water dissolving 12.5 parts of the salt at 0° C. and 17.3 parts at 17° C. Only 0.0172 part dissolves in 100 parts of alcohol at 16° C. The aqueous solution is very stable and does not lose hydrazoic acid when heated.

The dry salt is exploded by heat but not by shock, depositing a black powder of finely divided barium. The explosion temperature is 225° C. When the salt is carefully heated in vacuo evolution of nitrogen begins at 160° C., and will then continue at 120° C.