sulfide

Any of three classes of chemical compounds containing the element sulfur. The three classes of sulfides include inorganic sulfides, organic sulfides (thioethers), and phosphine sulfides. Sulfides of many metals are naturally occurring minerals; for example, pyrite (fool's gold) is a sulfide of iron, FeS. Sulfides are important components of lithium and sodium sulfide batteries, and phosphorous sulfides are used in the tips of strike-anywhere matches and in the preparation of industrial lubricant additives.