Sulfide

sulfide, also spelled sulphide, any of three classes of chemical compounds containing the element sulfur. The three classes of sulfides include inorganic sulfides, organic sulfides (sometimes called thioethers), and phosphine sulfides. Inorganic sulfides are ionic compounds containing the negatively charged sulfide ion, S²⁻; these compounds may be regarded as salts of the very weak acid hydrogen sulfide. Organic sulfides are compounds in which a sulfur atom is covalently bonded to two organic groups. Phosphine sulfides are formed from the reaction of organic phosphines with sulfur, in which the sulfur atom is linked to the phosphorus by a bond that has both covalent and ionic properties.

Sulfides of many important metallic elements are naturally occurring minerals. For example, pyrite, which is also called fool’s gold owing to its brassy yellow colour, is a sulfide of iron with the formula FeS₂. Pyrite is a major source of iron and is one of the most abundant of the sulfur minerals. Zinc, cadmium, mercury, copper, silver, and many other elements occur in nature as sulfides.