The structure, binding energies, and vibrational frequencies have been determined for the ground and low-lying excited states of ScCO2 in different coordination modes. Calculations have been performed using ab initio theoretical treatments that include electron correlation and methods based on the density functional approach. The eta(2)-C,O coordination in the (2)A’ State and the eta(2)-O,O coordination in the (2)A(1) State are the most stable ones, and they are almost degenerate in energy. The eta(1)-O mode lies 19 kcal/mol higher in energy, and the eta(1)-C coordination mode is found to be a transition state on the potential energy surface. The computed dissociation energy of ScCO2 is 17 kcal/mol.