The reactions of atomic Ni+, Cu+, and Zn+ with CS2 and COS are studied using guided-ion beam mass spectrometry. Different ion sources are used to characterize the relative reactivities of different electronic states of Nil and Cu+. Ground-state ions of all three metals undergo endothermic reactions to form MS+ from both CS2 and COS, as well as MCS+ and MCO+, respectively. In several cases, the cross sections for forming MCX+ (X = O, S) exhibit two endothermic features, which are assigned to the formation of different structural isomers or electronically excited product states. From the thresholds associated with forming MS+ and MCS+, we determine D-0(Ni+-S) = 2.46 +/- 0.04, D-0(Ni+-CS) = 2.43 +/- 0.10 eV, D-0(Cu+-S) = 2.07 +/- 0.15, D-0(Cu+-CS) = 2.47 +/- 0.12 eV, D-0(Zn+-S) = 2.05 +/- 0.12, and D-0(Zn+-CS) = 1.54 +/- 0.24 eV. The periodic trends in these values are discussed, and the nature of the bonding is analyzed. The results suggest that the initial mechanistic steps correspond to insertions of the metal ions into the C-S bonds of CXS (X = O, S).