Book excerpt: Reaction of the fragments {Ir(PEt3)n}+ with the monocarborane anion [closo-1-CB7H8]- causes an oxidative insertion to occur, and the iridium moiety to become a cluster vertex. This reaction provides two distinct, neutral, 9-vertex {IrCB7} products, depending on the ratio of iridium and phosphine reactants used. The iridium centers in these products have differing oxidation states, illustrating the exceptional ability of the smaller anionic monocarborane ligands to stabilize metals in higher oxidation states. Although salts of the 11-vertex anionic species [1,1,1-(CO)3-closo-1,2-FeCB9H10]- have resisted synthesis in the past, its analogue [1,1,1-(CO)3-2-Ph-closo-1,2-FeCB9H9]- has now been prepared. Moreover, two reactions demonstrating the derivative chemistry of this compound have been discovered. Previously, 10- and 12-vertex dicobalt monocarboranes were prepared and studied by treating monocarboranes with [Co2(CO)8]. This produced several poly-cobalt anions. New derivatives of these anions have been synthesized, using protocols developed since their discovery.