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.

Te): Experiment and Theory.-The strengths of the SeCl 2 -Cl -, SeOCl 2 -Cl -, SeBr 2 -Br -, and TeCl 2 -Clbonds are measured by determining thresholds for collision-induced dissociation in a flowing afterglow-tandem mass spectrometer. Bond energies and other properties for these molecules and are also computed by several high-level computational techniques, including B3LYP/aug-cc-pVTZ. There is excellent agreement between the experimental and computational energetics for , , and . The bond strengths increase in the order S < Se < Te. -(LOBRING, K. C.; HAO, C.; FORBES, J. K.; IVANOV, M. R. J.; BACHRACH*, S. M.; SUNDERLIN, L. S.; J.