Heats of formation and dissociation of methylsilanes and chlorosilanes and derived radicals

Abstract

The heats of formation for the complete set of methyl- and chloro-silanes of general formula SiMe_xCl_yH_4—(x+y), where x= 0–4 and y= 0-(4 –x), have been calculated using the MOBI method. Heats of formation for the radicals and molecules of general formula SiMe_xCl_yH_3—(x+y), where x= 0–3 and y= 0-(3—x), and SiMe_xCl_yH_2—(x+y), where x= 0–2 and y= 0-(2—x), have also been computed and a new value for ΔH^⊖_f(SiMe) is predicted. The heat of dissociation for each Si—H, Si—Cl and Si—C bond in all the above species has been calculated in addition to the heat of dissociation for the Si—Si bond in Si₂H₆, Si₂Me₆ and Si₂Cl₆. Satisfactory agreement with many published experimental data is obtained. The method yields results which are internally consistent, and many quantities, as yet experimentally undetermined, are predicted.