Hexasulfur is an inorganic chemical with the chemical formula . This allotrope of sulfur was first prepared by M. R. Engel in 1891 by treating thiosulfate with HCl. Hexasulfur is orange-red and forms a rhombohedral crystal. It is also called cyclo-, ÃÂ-sulfur, õ-sulfur, Engel's sulfur, and Aten's sulfur.
The most common name for the compound is "hexasulfur".
The preferred IUPAC name, cyclohexasulfane, is constructed according to compositional nomenclature.
Hexasulfur is the final member of the thiane heterocyclic series, in which every carbon atom is substituted with a sulfur atom, giving the systematic name "hexathiane", a valid IUPAC name using substitutive nomenclature.
Another valid IUPAC systematic name, cyclo-hexasulfur, is constructed using additive nomenclature.
Hexasulfur consists of rings of six 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 102.2ð. The sulfur atoms are equivalent.
A method of preparation involves the reaction of a polysulfane with sulfur monochloride: