Abstract The series of α, ω-dibromopermethylpolysilanes, Br (SiMe 2) n Br,(n= 2− 6) has been prepared by the action of bromine on dodecamethylcyclohexasilane. The mass spectra of these compounds, of the corresponding chlorine compounds Cl (SiMe 2) n Cl (n= 2− 6), and of the 1-chloropermethylpolysilanes Cl (SiMe 2) Me (n= 2, 3, 4, 6) have been recorded at 14 and 70 eV. For compounds with n> 3, the formation of the ions Si 3 Me 6 ...