Trithiazyl trichloride

Trithiazyl trichloride is the inorganic compound with the formula (NSCl)3. A white solid, it is a precursor to other sulfur nitrides, but has no commercial applications.

Structure
The molecule is a 6-membered ring of alternating nitrogen and sulfur atoms, where each sulfur atom is attached to one chlorine atom by a single bond. The molecule contains alternating single and double bonds in the S3N3 core. The molecule has C3v symmetry. The S3N3 core is slightly ruffled structure with S-N distances of 160.5 pm. The S-Cl distances are 208 pm, and the chlorine atoms are mutually cis. The S centers are tetravalent and pyramidal. In contrast to the NSCl connectivity, nitrosyl chloride has the connectivity ONCl.

Synthesis and reactions
Trithiazyl trichloride is obtained by chlorination of tetrasulfur tetranitride:
 * 3 S4N4 + 6 Cl2 → 4 (NSCl)3

At 100 °C in vacuum, thiazyl chloride trimer undergoes cracking to thiazyl chloride monomer, which is a green gas.
 * (\sN\dS(\sCl)\s)3 → 3 N\tS\sCl

In N≡S−Cl, chlorine is bonded to sulfur, in contrast to nitrosyl chloride O=N–Cl, where chlorine is bonded to nitrogen. In contrast, with six fewer electrons, cyanuric chloride is a planar ring.

Alkoxide or silver salts displace the chlorides:
 * (-NS(Cl)-)3 + 3 NaOR → (-NS(OR)-)3 + 3 NaCl
 * (-NS(Cl)-)3 + 3 AgX → (-NS(X)-)3 + 3 AgCl

Treating thiazyl chloride with sulfur in the presence of antimony pentachloride gives dithionitronium hexachloroantimonate:
 * SNCl + S  +  SbCl5  ->  [NS2]SbCl6

It reacts with nitriles to dithiadiazolium chlorides:
 * 6 RCN + 4 (NSCl)3 → 6 [RCN2S2]+Cl- + 3 Cl2 + 3 N2

The compound oxidizes to the S(VI) compound (NSOCl)3, which exists as isomers.