enkeltsulfid

Enkeltsulfid, or monosulfide, is a binary inorganic compound composed of sulfur bonded to a single metal or metalloid cation, giving the general formula MS. In this class the sulfur atom is present as the sulfide ion S2−, and the metal is typically in a +2 oxidation state, although other charges can occur depending on the element and crystal structure. Monosulfides are distinct from disulfides (such as MX2) and from polysulfides, where the ratio of sulfur to metal is greater than one.

Crystal structures for monosulfides vary with the metal. Many transition-metal monosulfides adopt close-packed lattices such as the rock-salt type, while zinc sulfide (ZnS) exists in zinc blende or wurtzite forms despite the 1:1 composition. Natural and synthetic monosulfides span a range of properties from metallic to semiconducting, with high melting points and often low solubility in water.

Occurrence and examples include the mineral troilite (FeS), and synthetic or naturally occurring sulfides such as ZnS (sphalerite or wurtzite), NiS, CoS, and CdS. These compounds are important as ores for metals and, in some cases, as functional materials; ZnS, for example, is a wide-bandgap semiconductor used in phosphors and optoelectronics.

Reactivity and safety: monosulfides can react with acids to release hydrogen sulfide (H2S), a toxic gas. They may oxidize in air to oxides or to sulfates over time. Monosulfides are distinguished from disulfides and from polysulfides by their 1:1 metal-to-sulfur composition.