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This paper collects the results obtained in different studies on the interaction of the CO 2 molecule with transition metal atoms, using matrix isolation FTIR spectroscopy and density functional theory (DFT). Late-transition metal atoms (Fe, Co, Ni and Cu) form one-to-one M(CO 2 ) complexes, while those from the left-hand side in the periodic table (Ti, V, and Cr) insert spontaneously into a CO bond yielding oxocarbonyl species. Owing to isotopic experiments with 13 CO 2 and C 18 O 2 , these results allow spectroscopic identification of carbon dioxide bonding modes in organometallic species containing CO 2 moiety. Special attention is paid to the interaction of CO 2 molecule with Ni and Ti atoms. In neat CO 2 matrices, it is shown that CO 2 is side-on coordinated to nickel in a 1:1 complex. The binding energy is weak (18 kcal mol −1 ). In argon diluted matrices, no reaction occurs, even after annealing. Interestingly, the coordination of CO 2 is promoted by adding N 2 in the rare gas matrix. This is rationalized by comparing the potential energy curves corresponding to the interaction of the Ni atom or the NiN 2 moiety with CO 2 . The binding energy is then 32 kcal mol −1 . DFT calculations show that Ti inserts with no energy barrier into a CO bond, resulting in an OTiCO insertion product, which is far more stable than any of the possible Ti(CO 2 ) complexes and reactive towards CO 2 . An intrinsic reaction path for the insertion process is investigated.