High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! A transition metal carbene complex is a organometallic compound featuring a divalent organic ligand. The divalent organic ligand coordinated to the metal center is called a carbene. All transition metals form such complexes. Many methods for synthesizing them and reactions utilizing them have been reported. The term carbene ligand is a formalism since many are not derived from carbenes and almost none exhibit the reactivity characteristic of carbenes. Described often as M=CR2, they represent a class of organic ligands intermediate between alkyls (-CR3) and carbynes ( CR). They feature in many catalytic reactions in the petrochemical industry and are of increasing interest in fine chemicals.