Pentasulphur Dinitride, S₅N₂

Pentasulphur Dinitride, S₅N₂ is prepared by the reaction between the solid sulphide and carbon disulphide under pressure at 100° C.:

S₄N₄ + 2CS₂ = S₅N₂ + S + 2CNS.

It is also found in the mother-liquors, resulting from the preparation of S₄N₄, and in the products of its decomposition by heat. It is a red mobile liquid of density 1.9, which is easily frozen; the solid melts at about 10° C. It can be vaporised with partial decomposition. Like the solid nitride, it is soluble in organic solvents and insoluble in water, aqueous acids, and alkalies, by which, however, it is hydrolysed, giving ammonia and sulphur. It can be kept in solution. The liquid itself decomposes slowly and explodes on heating.