Carbonyls

Abstract

Carbon monoxide forms a host of metal carbonyl complexes, at least one for every transition metal. Mononuclear, polynuclear, and heteronuclear metal carbonyls are all known. The complexes, of general formula M x (CO) y , may be charged or neutral; the metal or metals are in the zero oxidation state. Metal carbonyls are useful as reagents and catalysts in organic synthesis, and play a role in both the Reppe and the oxo processes, as well as in the preparation of synthetic fuels and in vapor deposition of purified metals. The structure and bonding of the metal carbonyls, including that of cluster compounds, follow well‐defined rules. Synthesis of the metal carbonyls usually proceeds either from the reduction of the corresponding metal, initially in the form of a metallic salt, or via condensation of lower molecular weight compounds.