Barium Hyponitrite, BaN₂O₂

Barium Hyponitrite, BaN₂O₂, may be obtained as a crystalline precipitate by the action of sodium hyponitrite on barium chloride solution, or of the silver salt on an ammoniacal solution of barium acetate and subsequent washing of the precipitate with ammonia, alcohol, and ether, followed by rapid drying in air. Large needles are obtained when very dilute solutions are used. It is also produced by the action of nitric oxide on barium ammonium.

It is obtained both as the anhydrous salt and as the tetrahydrate, BaN₂O₂.4H₂O. The tetrahydrate readily effloresces. Barium hyponitrite is only slightly soluble in water, the solution giving an alkaline reaction. It is decomposed by dilute acids with the evolution of nitrous acid.

An acid salt, BaH₂(N₂O₂)₂, crystallising in long needles and readily soluble in water, may also be prepared, but not in a pure condition.

By crystallising the neutral salt from acetic acid solution a compound, BaN₂O₂.Ba(CH₃COO)₂.2CH₃COOH.3H₂O, is obtained. It is less stable than the corresponding calcium and strontium compounds.