Tungsten(III) chloride
Tungsten(III) chloride (WCl3) is a chemical compound of tungsten and chlorine. It is a dark brown to black solid, highly reactive towards air and moisture. Its structure differs from that of many other transition metal trichlorides. Unlike many which adopt a layered structure, WCl3 forms a complex polymeric structure due to the presence of metal-metal bonding. This results in a distorted octahedral coordination geometry around each tungsten atom.
The compound is relatively uncommon compared to higher oxidation state tungsten chlorides such as tungsten(VI) chloride (WCl6). Its synthesis typically involves the reduction of higher-valent tungsten chlorides, often using a reducing agent like hydrogen or aluminum. Specific synthesis methods often require carefully controlled conditions of temperature and pressure to avoid the formation of other tungsten chlorides or tungsten oxychlorides.
Due to its reactivity and instability in air, handling WCl3 requires an inert atmosphere, typically employing techniques like Schlenk line or glovebox methods. Its chemical properties are largely defined by its propensity to undergo oxidation and its tendency to participate in reactions involving metal-metal bond breaking and formation. It is used as a precursor in the synthesis of other tungsten compounds, and its investigation is important in understanding the chemistry of tungsten in lower oxidation states. Further research is needed to fully explore its potential applications.