The hybrid B3LYP density functional method together with cluster models have been used to explore the adsorption and adsorption-induced dimerization and trimerization of CO over the low-coordinated oxygen anions of MgO solid. The calculations reveal the following: (i) monomeric, dimeric, and trimeric adsorptions on the low-coordinated anions lead to the formation of anionic surface species CmOm+12- (m = 1-3); (ii) dioxoketene ion C2O32- Which has a strong C=C bond can be formed at O-3C site, whereas at O-4C site the formation of tripler trans-C2O32- adspecies is thermodynamically favorable over the formation of singlet C2O32- adspecies which has a weak C-C bond; (iii) The C3O42- surface species does have a ketenic group, i.e., O=C=C <, and shows substantial stability. The calculated energetics suggests that the dimeric adspecies are unlikely to be stable adspecies, but may be the intermediates for the formation of higher oligomeric adspecies of CO. The calculated IR frequencies of CmOm+12- (m = 1-3) surface complexes have been compared with the experimental IR spectra.