The strengths of the SeCl2-Cl-, SeOCl2-Cl-, SeBr2-Br-, and TeCl2-Cl- bonds have been measured to be 133 +/- 9, 150 +/- 10, 110 +/- 6, and 170 +/- 7 kJ mol(-1), respectively, by determining thresholds for collision-induced dissociation in a flowing afterglow-tandem mass spectrometer. These values are stronger than the previously measured D(SCl2-Cl-) and D(SOCl2-Cl-), both 85 +/- 8 kJ mol(-1). Bond energies and other properties for these molecules and TeOCl3- have also been computed by several high-level computational techniques, including B3LYP/aug-cc-pVTZ. There is excellent agreement between the experimental and computational energetics for SeCl3-, SeOCl3-, and TeCl3-. The bond strengths increase in the order S < Se < Te.