The octanuclear cluster [Re5Ir(mu(6)-C)(CO)(17)(mu(3)-Re(CO)(3))(2)](2-) loses a [Re(CO)(3)](+ )capping unit in refluxing acetonitrile to give the heptanuclear cluster [Re5Ir(mu(6)-C)(CO)(17)(mu(3)-Re(CO)(3))](3-) The latter compound can be capped with [AuPPh3](+) groups to form the monogold and digold derivatives [Re6Ir((CO)(20)(AuPPh3)](2-) and [Re6IrC(CO)(20)(AuPPh3)(2)](-). These three new anionic clusters have been isolated as PPN+ and/or PPk(4)(+) salts and are formulated on the basis of microanalytical and FAB mass spectrometric data. The solid-state structure of [PPh4][Re6Ir(mu(6)-C)(CO)(20)(mu 3-AUPPh(3))(2)]. CH2Cl2 has been determined by X-ray diffraction. Crystal data : triclinic, space group P (1) over bar, a 13.1182(1) Angstrom, b = 15.1806(1) Angstrom, c = 23.4061(3) Angstrom, alpha = 74.251(1)degrees, beta = 82.058(1)degrees, gamma = 70.306(1)degrees Z = 2. Further information on the structures of the compounds in solution has been derived from C-13 and P-31 NMR studies.