Molecular polarisability. The conformations of triphenylsilane, chlorotriphenylsilane, and bromotriphenylsilane as solutes in benzene

Abstract

Dipole moments and molar Kerr constants are recorded for the molecules R₃SiX (R = CH₃, C₆H₅; X = H, Cl, or Br) as solutes in benzene. Analysis of the experimental data shows that (a) the groups C₃SiX are near-isotropically polarisable, (b) the dispositions of the C₆H₅ groups in the molecules (C₆H₅)₃SiX examined are virtually independent of the size and electronegativity of the atom X, and are defined by rotations ϕ of 47°± 3°(in the same sense, which preserves C₃-symmetry) from a theoretical model, having ϕ= 0°, in which the aromatic ring-planes intersect along the molecular symmetry axis.