Thermal decomposition kinetics of polysilanes: Disilane, trisilane, and tetrasilane

Abstract The decomposition kinetics of disilane with added butadiene, trisilane both neat and with added butadiene, trimethylsilane or H 2 , 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 SiH 4 , Si 2 H 6 , Si 3 H 8 , C 4 H 6 , Me 3 SiH, and H 2 toward SiH 2 and SiH 3 SiH are also determined. Other results include the heat of formation of silylsilylene, ΔH (SiH 3 SiH) = 75.3 Kcal/mol, and the activation energy for 1,1‐H 2 elimination from disilane ( E H 2 = 57.8 kcal/mol).