Ab initio molecular orbital theory has been used to characterize both gaseous singlet and triplet (CO2P)(+) species. Five stable molecular structures have been found for each of the spin multiplicities, at the MP2/6-31G* level of theory, one planar cyclic, two ion-molecule complexes, and two ion molecule-molecule complexes. Only the triplet states of the (OP-CO)+ complexes have been found to have substantial hemibond character. For all other complexes studied, an electrostatic type of interaction is found to dominate. The electrostatic singlet (1)A’ state of the OP+-CO complex has been predicted to be the most stable of all. However, our calculations demonstrate that the P+-OPO ion-molecule complex has the greatest binding energy. Finally, vibrational spectra of these species, which may help in their detection, are discussed.