Laser-ablated Rh atoms react to give RhO, the linear dioxide ORhO, the side-bound dioxygen adduct (O-2)RhO2, and several ORhO(O-2) complexes. In addition, a large number of Rh-x(O-2)(y) complexes are observed, but only Rh(O-2) and(O-2)Rh(O-2) can be identified with the support of DFT frequency calculations. These calculations also characterize (O-2)RhO2 as a peroxide with rhodium approaching the +6 oxidation state and (O-2)Rh(O-2) between a disuperoxo and diperoxo species. Comparisons among the Co, Rh, and Ir dioxygen systems are given.