Metallsulfider

Metallsulfider are chemical compounds consisting of metal ions bonded to sulfide ions (S2−). They form a broad class that includes simple binary sulfides such as FeS, ZnS and PbS, as well as more complex phases with non-stoichiometric compositions or polysulfide ligands. In geology they are known as sulfide minerals and can occur as discrete crystallites or in solid solutions.

Most metals form sulfides; transition metals in particular yield a wide variety of structures, including rock-salt type (FeS), hexagonal forms such as wurtzite or sphalerite (ZnS), pyrite-type FeS2, and copper sulfide phases such as CuS. Layered dichalcogenides like MoS2 and WS2 have two-dimensional structures that give lubricating properties and notable catalytic activity.

Properties: metal sulfides generally have high melting points and are insoluble in water. Their electronic properties range from insulating (ZnS) to semiconducting and catalytic (MoS2, WS2), with some sulfides also showing metallic or mixed behavior. They appear in minerals with colors from black to yellow, partly influenced by composition and crystal structure.

Occurrence and production: sulfide minerals are common ore sources for metals; they form in magmatic, hydrothermal and sedimentary environments. Commercially they are produced by mining and ore concentration, followed by smelting and refining to extract the metal. In some cases, sulfides are formed synthetically by sulfidation of oxides or precipitation from sulfide solutions.

Uses: ores of iron, zinc, copper, lead and nickel are processed to obtain metals. Some sulfides serve as semiconductors (ZnS, CdS), catalysts (MoS2, WS2 for hydrogen evolution), or lubricants (MoS2, WS2). They also have roles in pigments and photovoltaic materials.

Safety: sulfide minerals can release toxic hydrogen sulfide gas under acidic conditions; dust and certain sulfides contain hazardous metals, requiring proper handling and containment.