Nitrogen Persulphide, NS₂

When nitrogen sulphide, N₄S₄, is sublimed with sulphur at 125° C., Nitrogen Persulphide, NS₂, is obtained as a dark-red liquid, somewhat resembling bromine, which, at the temperature of solid carbon dioxide, solidifies to a pale yellow solid. The liquid has a penetrating odour resembling that of iodine, and can be distilled unchanged in a vacuum. At ordinary temperatures it decomposes slowly, forming yellow nitrogen sulphide and sulphur. The persulphide is decomposed by water into free sulphur, and ammonium salts are formed.