DIELECTRIC CONSTANT AND REFRACTIVE INDEX OF WEAK COMPLEXES IN SOLUTION

The effect on the dielectric constant and refractive index of weak complex formation between the components of a binary solution is calculated. Equations are developed which relate the deviations from additivity of the molar polarization and the molar refraction at infinite wavelength to the equilibrium constant for complex formation and the atomic polarizability and dipole moment of the complex. Dielectric constant and refractive index measurements are reported for the benzene-hexafluorobenzene system. These data are consistent with the presence of a weak complex in solution and from them the atomic polarizability increment and dipole moment of the complex are estimated. The values of these quantities indicate that charge-transfer effects are not of primary importance for stability of the complex.