Molecular polarisability. The molar Kerr constants of boron trihalides

Abstract

Molar Kerr constants are reported for boron trichloride and boron tribromide in cyclohexane and for boron trifluoride and boron trichloride in dioxan. The anisotropic electron polarisabilities of the ‘isolated’ boron trichloride and boron tribromide molecules are derived from the measurements in cyclohexane and resolved to yield the appropriate boron (sp²)–halogen bond parameters. Polarity and polarisability changes arising from complex formation of the boron trihalides with dioxan are discussed.