The reactions of scandium atoms and O-2 have been reinvestigated using matrix isolation infrared spectroscopy and density functional theory calculations. A series of new oxygen-rich scandium oxide/dioxygen complexes were prepared and characterized. The ground state scandium atoms react with dioxygen to form OSC(eta(2)-O-3), a side-on bonded scandium monoxide-ozonide complex. The OSc(eta(2)-O-3) complex rearranges to a more stable Sc(eta(2)-O-2)(2) isomer under visible light irradiation, which is characterized to be a side-on bonded superoxo scandium peroxide complex. The homoleptic trisuperoxo scandium complex, Sc(eta(2)-O-2)(3), and the superoxo scandium bisozonide complex, (eta(2)-O-2)Sc(eta(2)-O-3)(2), are also formed upon sample annealing. The Sc(eta(2)-O-2)(3) complex is determined to have a D-3h symmetry with three equivalent side-on bonded superoxo ligands around the scandium atom. The (eta(2)-O-2)Sc(eta(2)-O-3)(2) Complex has a C-2 symmetry with two equivalent side-on bonded O-3 ligands and one side-on bonded superoxo ligand.