sulfurs

Sulfurs refer to the chemical element sulfur and its various forms, including elemental sulfur and sulfur-containing compounds. Sulfur is a nonmetal with the symbol S and atomic number 16. It occurs widely in nature, notably in volcanic gases and mineral deposits, and is essential to many biological processes.

Elemental sulfur occurs mainly as cyclic S8 molecules and forms yellow crystals. It has a melting point of 115.21 °C and a boiling point of 444.6 °C. It is insoluble in water, soluble in carbon disulfide, and relatively unreactive at room temperature, though it reacts with oxidizers and at elevated temperatures. Sulfur can exist in several allotropes, including other ring sizes and polymeric chains, but S8 is the most stable under ambient conditions.

In chemistry, sulfur displays a range of oxidation states, from -2 in sulfides (S2−) to +6 in sulfates (SO4^2−). It forms a wide array of compounds, including sulfides, sulfites, sulfates, thiosulfates, and organosulfur compounds such as thiols and sulfides. In biology, sulfur-containing amino acids (cysteine, methionine) are essential.

Industrial relevance: the dominant application is sulfuric acid production via the contact process, used for fertilizers, detergents, and many chemicals. Other uses include vulcanization of rubber, pesticides, and pharmaceuticals. Sulfur also features in pigments, matches, and flame retardants.

Safety: sulfur combustion produces sulfur dioxide; sulfur compounds can be irritating; hydrogen sulfide is toxic. Environmental concerns include acid rain from sulfur oxides.

Etymology: from Latin sulfur, brimstone; spelling variations include sulfur and sulphur.