Molybdenum hexacarbonyl
Molybdenum hexacarbonyl is the chemical compound with the formula Mo6. This colorless solid, like its chromium, tungsten, and seaborgium analogues, is noteworthy as a volatile, air-stable derivative of a metal in its zero oxidation state.
Structure and properties
Mo6 adopts an octahedral geometry consisting of six rod-like CO ligands radiating from the central Mo atom. A recurring minor debate in some chemical circles concerns the definition of an "organometallic" compound. Usually, organometallic indicates the presence of a metal directly bonded via a M–C bond to an organic fragment, which must in turn have a C–H bond.Like many metal carbonyls, Mo6 is generally prepared by "reductive carbonylation", which involves reduction of a metal halide with under an atmosphere of carbon monoxide. As described in a 2023 survey of methods "most cost-effective routes for the synthesis of group 6 hexacarbonyls are based on the reduction of the metal chlorides with magnesium, zinc or aluminium powders... under CO pressures".
Occurrence
Mo6 has been detected in landfills and sewage plants, the reducing, anaerobic environment being conducive to formation of Mo6.Inorganic and organometallic derivatives
Molybdenum hexacarbonyl is a popular reagent in research. One or more CO ligands can be displaced by other ligands. Examples:Some of these species are suited for substitution. For instance, the reaction of with triphenyl phosphine gives cis- and trans-., whereas treatment with KTp and sodium cyclopentadienide gives − and − anions, respectively. These anions react with a variety of electrophiles. A related source of Mo3 is cycloheptatrienemolybdenum tricarbonyl.