Bond Dissociation Enthalpy Ratios Involving Pentaatomic 16-Valence Electron Anions (pp. 293-304)
Authors: Carol A. Deakyne and Joel F. Liebman
Abstract: Quantum chemical calculations have been carried out at the G2 level of theory to determine atomization enthalpies for isovalently/isoelectronically related pairs of 10-valence electron [HYX]– and 16-valence electron [HYXYH]– ions. Here, X– is a group 13 atom and Y is a group 15 atom. The atomization enthalpies were then used to evaluate the bond dissociation enthalpy ratio /D°m([HYX]–), where the average bond dissociation energy of the pentaatomic anion is divided by the bond dissociation enthalpy of the triatomic anion. Again, the ratios for the nine [HYXYH]–/[HYX]– pairs are nearly constant, with a mean value of 0.92 ± 0.02. The thermochemical data and equilibrium structures found for these anions have been compared and contrasted to the results found earlier for the valence isoelectronically related neutrals HYXYH and HYX (X is a group 14 atom) and cations [HYXYH]+ and [HYX]+ (X+ is a group 15 atom).