Hexasulfur

Hexasulfur is an inorganic chemical with the chemical formula S6. This allotrope was first prepared by M. R. Engel in 1891 by treating thiosulfate with HCl. Cyclo-S6 is orange-red and forms a rhombohedral crystal. It is called ρ-sulfur, ε-sulfur, Engel's sulfur and Aten's sulfur. Another method of preparation involves the reaction of a polysulfane with sulfur monochloride:


 * H2S4 + S2Cl2 → cyclo\-S6 + 2 HCl (dilute solution in diethyl ether)

Nomenclature
The name hexasulfur is the most commonly used and preferred IUPAC name and is constructed according to the compositional nomenclature, and cyclohexasulfane. It is also the final member of the thiane heterocyclic series, where every carbon atom is substituted with a sulfur atom, thus the systematic name hexathiane, a valid IUPAC name, is constructed according to the substitutive nomenclature. Another valid IUPAC systematic name cyclo-hexasulfur is constructed according to the additive nomenclature.

Structure
This chemical consists of rings of 6 sulfur atoms. It is thus a simple cyclosulfane and an allotrope of sulfur. Hexasulfur adopts a chair configuration similar to that of cyclohexane, with bond angles of 102.2°. The sulfur atoms are equivalent.