Sulfuret

Sulfuret, commonly encountered in English as sulfide, is a class of chemical compounds in which sulfur exists as the sulfide anion (S2−). The term is used in older chemical literature and in mineralogy to refer to minerals composed largely of metal sulfides.

Most sulfures are binary compounds of a metal with sulfur, with general formula MX or MxSy, such as iron sulfide FeS, zinc sulfide ZnS, or copper sulfide CuS. Some sulfide minerals contain more complex anions such as disulfide (S2^2−), as in FeS2, the mineral pyrite.

Sulfide minerals are widespread in the Earth's crust, especially in reducing environments such as hydrothermal veins, magmatic sulfide deposits, and certain sedimentary basins. They form through magmatic differentiation, hydrothermal activity, and near-surface weathering processes. Economically, sulfide minerals are important ore sources for metals including copper, zinc, lead, nickel, and iron.

Sulfides typically have metallic luster and a range of hardness, with variable solubility in acids. They are often opaque with a characteristic streak, and many are brittle. Some sulfides serve as semiconductors or pigments (for example, zinc sulfide in phosphors). Oxidation of sulfides can yield sulfates or oxides and may release toxic hydrogen sulfide gas under acidic conditions.

Sulfides are distinct from sulfates and sulfites, which contain oxidized sulfur in different anions (SO4^2− and SO3^2−). See also: list of sulfide minerals, pyrite, galena, sphalerite, chalcopyrite.