Group I : the alkali and coinage metals. Group II : the alkaline earths and zinc and its congeners. Carbaboranes, including their metal complexes. Group III : boron, aluminium, gallium, indium, and thallium. Group IV : the silicon group. Group V : arsenic, antimony, and bismuth. Metal carbonyls. Organometallic compounds containing metal-metal bonds. Complexes containing metal-carbon sigma-bonds of the groups scandium to manganese, including carbenes and carbynes. Complexes containing metal-carbon sigma-bonds of the groups iron, cobalt and nickel, including carbenes and carbynes. Hydrocarbon-metal ¹-complexes, other than ¹-cyclopentadienyl and ¹-arene complexes. ¹-cyclopentadienyl, ¹-arene and related complexes.