Oxidation of [RU(3)(CO)(6)(mu-dppm)(3)], dppm = Ph(2)PCH(2)PPh(2), by silver(I) and O-2 or Me(3)NO gives the oxo cluster complex [Ru-3(mu(3)-O)(mu 3-CO)(CO)(3)(mu-dppm)(3)], 3, which can undergo reversible protonation to give the related hydroxo cluster [RU(3)(mu(3)-OH)(mu(3)-CO)(CO)(3)(mu-dPPm)(3)](+) The structure of 3 has been determined [monoclinic, P2(1)/n, a = 19.771(2) Angstrom, b = 29.711(2) Angstrom, c 13.007(2) Angstrom, beta = 94.01(9)degrees, V = 7622(1) Angstrom(3), Z = 4, R(F) = 0.063]. These clusters are sterically congested and exhibit an interesting new form of fluxionality in clusters based on the M(3)(mu-dppm)(3) unit.