ABSTRACT
Low oxidation state transition metal clusters are surrounded and stabilised by a shell o f ligands. The ligands that are encountered are generally much the same as those observed in mononuclear organometallic complexes. Carbon monoxide, phosphines, nitric oxide, hydrides, 7t-bonded ligands such as alkenes, alkynes, cyclopentadienyls and arenes are all common ligands in cluster chemistry. However, these ligands often display a much richer coordination chemistry when bound to clusters, as many bonding modes are available in which the ligands can interact with more than one metal centre.
