Dithiotetrathiazyl Chloride, N₄S₆Cl₂

Dithiotetrathiazyl Chloride, N₄S₆Cl₂, may be prepared by the action of nitrogen sulphide, N₄S₄, on sulphur monochloride in the cold. It is deposited as a black, crystalline solid, which on heating decomposes thus:

3N₄S₆Cl₂ = S₂Cl₂ + 4N₃S₄Cl. Crystals of dithiotetrathiazyl chloride make a crimson mark on paper.

By the action of nitrogen sulphide, N₄S₄, on a chloroform solution of nitrogen chlorosulphide, N₄S₄Cl₂, a copper-coloured compound is obtained, possibly of composition N₃S₃Cl. This compound is less soluble in chloroform than nitrogen chlorosulphide and does not change so readily. It decomposes with a feeble explosion when strongly heated.

Nitrogen sulphide, N₄S₄, forms various compounds with "sulphur dichloride" when the two are mixed in carbon disulphide solution. In the presence of excess of "sulphur dichloride" the product is thiodithiazyl dichloride, N₂S₃Cl₂ or N₄S₄.2SCl₂. This compound has also been prepared by the union of " sulphur dichloride " with thiotrithiazyl chloride. Thiodithiazyl dichloride forms yellow crystals which decompose in air, losing a part of their sulphur chloride and becoming reddish-black in colour. With concentrated sulphuric acid, hydrogen chloride is liberated and a red solution is formed. Water acts on the dichloride with formation of a black compound of composition N₂S₃O₃. Chlorine reacts with formation of nitrogen chlorosulphide, N₄S₄Cl₂. At 100° C. thiodithiazyl dichloride decomposes with evolution of chlorine and nitrogen chlorosulphide. The residue consists of thiotrithiazyl chloride.

A red compound of composition N₄S₄.SCl₂ is also obtained by the interaction of "sulphur dichloride" and nitrogen sulphide in carbon disulphide solution, and consequently it is formed during the preparation of nitrogen sulphide by the action of ammonia on the dichloride in carbon disulphide. It decomposes at 100° C., forming the compound 3N₄S₄.2SCl₂, which substance is also obtained when excess of nitrogen sulphide is added to " sulphur dichloride." 3N₄S₄.2SCl₂ is a yellow powder, which is slightly soluble in carbon disulphide and yields a blue substance with water. A fleeting violet coloration is produced by the action of alcoholic potash.