Ammonium Sulfide

Ammonium sulfide, (NH₄)₂S, is obtained, in the form of micaceous crystals, by passing hydrogen sulfide mixed with a slight excess of ammonia through a well-cooled vessel; the hydrosulfide NH₄?HS is formed at the same time. It dissolves readily in water, but is probably partially dissociated in solution. The hydrosulfide NH₄?HS can be obtained as a white solid, by mixing well-cooled ammonia with a slight excess of hydrogen sulfide. According to W. P. Bloxam (Jour. of Chem. Soc., 1895, lxvii. p. 283), if hydrogen sulfide is passed into strong aqueous ammonia at ordinary temperature, the compound (NH₄)₂S.2NH₄HS is obtained, which, on cooling to 0°C and passing more hydrogen sulfide, forms the compound (NH₄)₂S.12NH₄HS. An ice-cold solution of this substance kept at 0°C and having hydrogen sulfide continually passed through it gives the hydrosulfide. Several complex polysulfides of ammonium have been isolated, for details of which see Bloxam's paper quoted above. Compounds are known which may be looked upon as derived from ammonia by the replacement of its hydrogen by the sulfo-group (HSO₃); thus potassium ammon-trisulfonate, N(SO₃K)₃2H₂O, is obtained as a crystalline precipitate on the addition of excess of potassium sulfite to a solution of potassium nitrite, KNO₂ + 3K₂SO₃ + 2H₂O = N(SO₃K)₃ + 4KHO. It can be recrystallized by solution in alkalies. On boiling with water, it is converted, first into the disulfonate NH(SO₃K)₂ thus, N(SO₃K)₃ + H₂O = NH(SO₃K)₂ + KHSO₄, and ultimately into the monosulfonate NH₂?SO₃K. The disulfonate is more readily obtained by moistening the nitrilosulfonate with dilute sulfuric acid and letting it stand for twenty-four hours, after which it is recrystallized from dilute ammonia. It forms monosymmetric crystals which by boiling with water yield amidosulfonic acid. (See also E. Divers, Jour. of Chem. Soc., 1892, lxi. p. 943.) Amidosulfonic acid crystallizes in prisms, slightly soluble in water, and is a stable compound.