Theoretical studies of the transition metal-carbonyl systems MCO and M(CO)2, M=Ti, Sc, and VThe reactions of Sc + , Ti + , and V + with CO are studied as a function of translational energy in a guided-ion-beam tandem mass spectrometer. Formation of both metal-carbide and metaloxide ions are observed and rationalized by a direct atom abstraction mechanism. At high energies, the ScC + and ScO + cross sections exhibit additional features that are unusual but can be explained by an impulsive pairwise mechanism and formation of excited-state product ions, respectively. Thresholds of the reaction cross sections are interpreted to give the 0 K bond energies (in eV) DO(ScC+) = 3.34 ± 0.06, DO(TiC+) = 4.05 ± 0.24, DO(VC+) = 3.87 ± 0.14, DO(ScO+) = 7.11 ± 0.08, DO(TiO+) = 6.88 ± 0.07, and D o(VO + ) = 5.81 ± 0.17. Additional studies are used to help verify the bond energy for ScO + and yield a recommended value of 7.14 ± 0.11 e V. The nature of the bonding in MO + and MC + is discussed and compared for these three metal ions.