Restricted Hartree-Fock, configuration interaction and perturbation ca
lculations were performed to establish the bond strengths, the stable
geometries, and the electron distributions of the MCO(2) molecules whe
re M = Ca - Mn, Cu, Zn. All the MCO(2) molecules except the CuCO2 and
ZnCO2 are shown to be stable with respect to dissociation. The ground
states have maximum spin electron configurations. Other high-spin stat
es, which only differ from the ground states by electron permutations
within the nonbonding d subshell, are very close to the ground state.
The spin populations show a transfer of one metal valence electron to
the CO2 group, which is essentially localized at the carbon atom.