REDUCTION OF CARBON DIOXIDE TO OXALATE BY LITHIUM ATOMS: A MATRIX ISOLATION STUDY OF THE INTERMEDIATE STEPS

Article abstract of DOI:10.1016/0022-2860(85)80197-6

The codeposition of lithium atoms and carbon dioxide molecules in a krypton matrix at 9 K produces infrared absorptions attributable to five different species.Concentration effects, photosensitivity, annealing and isotopic substitutions provide information on the structure of each of these complexes, which have 1/1, 1/2 and 2/2 Li/CO2 stoichiometry.The two major reaction products have been identified as two isomers of LiCO2.In each case, vibrational data are consistent with a bent structure of the CO2 groups, indicating that, by analogy with the structure of CO2^- anion in the gas phase, these complexes are stabilized by a strong transfer of the lithium valence electron to the CO2 group.Addition of another CO2 molecule produces two other intermediate steps to further reduction of carbon dioxide, achieved in the final high-stoichiometry product identified as lithium oxalate, Li2C2O4.