Thiotrithiazyl Chloride, N₃S₄Cl

Thiotrithiazyl Chloride, N₃S₄Cl, is obtained when nitrogen sulphide, N₄S₄, is added to "sulphur dichloride" dissolved in its own volume of chloroform or carbon tetrachloride and the resulting mixture boiled. It is more conveniently prepared by heating nitrogen sulphide with acetyl chloride. Thiotrithiazyl chloride is a yellow, crystalline solid, insoluble in most solvents but slightly soluble in thionyl chloride, from which it crystallises in brownish crystals. It is decomposed by water, forming ammonium trithionate, ammonium chloride and sulphur. Similarly it yields trithionic acid with dilute hydrochloric acid:

2N₃S₄Cl + 12H₂O + 4HCl = 2H₂S₃O₆ + 6NH₄Cl + 2S.

With concentrated nitric acid, thiotrithiazyl chloride yields thiotrithiazyl nitrate, N₃S₄.NO₃. Like nitrogen sulphide, with dilute aqueous alkali it yields sulphite and thiosulphate. When thiotrithiazyl chloride is boiled with alcohol and the resulting solution treated with a few drops of alcoholic potash, an intense violet-red coloration is produced. Ammonia gas is rapidly absorbed by the dry compound, which then explodes violently after a few minutes. If thiotrithiazyl chloride is suspended in chloroform and submitted to the action of a stream of ammonia gas, the liquid becomes orange-red; ammonium chloride and ammonium sulphide are produced and nitrogen sulphide is regenerated.