Dielectric Properties of Slightly Polar Organic Liquids as a Function of Pressure, Volume, and Temperature

The dielectric constant and density have been measured simultaneously for carbon tetrachloride, carbon disulfide, isopentane, and toluene. The Clausius–Mossotti polarization for all liquids at constant temperature shows a linear decrease with increasing density. Only isopentane and toluene show a temperature dependence of the Clausius–Mossotti polarization at constant density consistent with the presence of a permanent dipole moment. The dipole moments derived from the constant density data are 0.105 D for isopentane and 0.332 D for toluene. Also, the Böttcher–Onsager equation is shown to be incompatible with the measured data.