THERMAL-DECOMPOSITION KINETICS OF POLYSILANES - DISILANE, TRISILANE, AND TETRASILANE

The decomposition kinetics of disilane with added butadiene, trisilane both neat and with added butadiene, trimethylsilane or H2, and normal and iso‐tetrasilane both neat and in the presence of added butadiene are reported. Arrhenius parameters of the primary dissociation reactions are determined: A‐factors suggest that polysilane decompositions (1) have similar intrinsic activation entropies (ΔS‡ ≈ 6.2 ± 5 e.u.) and (2) have activation energies which increase with increasing reaction endothermicities. Relative trapping efficiencies of SiH4, Si2H6, Si3H8, C4H6, Me3SiH, and H2 toward SiH2 and SiH3SiH are also determined. Other results include the heat of formation of silylsilylene, ΔH ∘f (SiH3SiH) = 75.3 Kcal/mol, and the activation energy for 1,1‐H2 elimination from disilane (EH2 = 57.8 kcal/mol). Copyright © 1990 John Wiley & Sons, Inc.