The kinetic energy dependence of the reactions of Fe-n(+) (n=1-18) with CO2 are studied in a guided ion-beam mass spectrometer. The primary product ions are FenO+, which then decompose by sequential loss of iron atoms as the kinetic energy is increased. Simple collision-induced dissociation to form the Fe-n-1(+) product ions is also observed. Large cluster ions, n greater than or equal to 9, form the FenCO2+ adduct at low kinetic energies. The cross section for the primary reaction, Fe-n(+)+CO2-->FenO++CO, exhibits an interesting bimodal energy behavior that is discussed in some detail. Fe-n(+)-O bond energies are measured and found to compare well with previous measurements obtained from guided ion-beam studies of the Fe-n(+)+O-2 systems. The trends in this thermochemistry are discussed and compared to bulk phase values. (C) 1997 American Institute of Physics.