Nuclear magnetic resonance studies of mixed dihalogenosilanes and related species

Exchange between dihalogenosilanes and hydrogen halides leads to the formation of mixed dihalogenosilanes; 1H chemical shifts and 29SiH coupling constants have been obtained, and equilibrium constants measured for the reactions SiH2X2+ SiH2Y2⇌ 2SiH2XY. The usual additivity relationships are not well obeyed by the n.m.r. parameters in these systems. Evidence is presented for the existence of the species XSiH2CN (X = Cl, Br, I). The Raman spectrum of SiH2ICI has also been obtained.