Barium Hexammoniate, Ba(NH₃)₆

Barium Ammonium, Barium Hexammoniate, Ba(NH₃)₆, is obtained as a. red, bronze-like solid by passing ammonia over metallic barium below 28° C. At -23° C. a blue solution of the compound in liquid ammonia is formed, and at -50° C. a second liquid phase separates. Below -15° C. barium ammonium is stable. At higher temperatures it decomposes to form the amide. The following values have been found for the dissociation pressure of ammonia at different temperatures: 13 mm. at -25° C., 50 mm. at -3° C., and 60 mm. at 0° C. The heat of formation of barium hexammoniate from barium and ammonia is 9.68 Cal. Barium ammonium inflames spontaneously in the air and reacts violently with water. It absorbs oxygen giving a mixture of barium peroxide and oxide. With nitric oxide it forms barium hyponitrite, and with carbon monoxide, barium carbonyl.

Barium ammonium may also be obtained by dissolving a 60 per cent, barium amalgam in liquid ammonia.