The Static Dielectric Constants of the Liquified Fluoromethanes

Abstract

The static dielectric constants of CF4, CHF3, CH2F2, and CH3F have been measured at temperatures ranging from their melting points to their normal boiling points. The molar polarization of CF4 agrees with that of the gas phase to within experimental error. The deviation of the dielectric constants of the polar fluoromethanes from the values predicted by the Onsager equation cannot be fully due to their non-spherical shape.It is postulated that although a significant parallel dipole correlation may be present in each fluoromethane, the polarization resulting from the liquid lattice vibrations, may account for much, or all, of the effect in CH3F and CH2F2.