J. Phys. IV France 09 (1999) Pr8-23-Pr8-31
Heats of formation and bond energies in group III compoundsM.D. Allendorf1, C.F. Melius1 and C.W. Bauschlicher Jr.2
1 Sandia National Laboratories, Livermore, CA 94551-0969, U.S.A.
2 NASA Ames Research Center, Moffett Field, CA 94035, U.S.A.
We present heats of formation and bond energies for Group-III compounds obtained from calculations of molecular ground-state electronic energies. Data for compounds of the form MX0 are presented, where M = B, Al, Ga, and In, X = H, Cl, and CH3, and n = 1-3. Energies for the B, Al, and Ga compounds are obtained from G2 predictions, while those for the In compounds are obtained from CCSD(T)/CBS calculations ; these are the most accurate calculations for indium-containing compounds published to date. In most cases, the calculated thermochemistry is in good agreement with published values derived from experiments for those species that have well-established heats of formation. Bond energies obtained from the heats of formation follow the expected trend (Cl >> CH3 - H). However, the CH3M-(CH3)2 bond energies obtained for trimethylgallium and trimethylindium are considerably stronger (> 15 kcal mol-1) than currently accepted values.
© EDP Sciences 1999