Microwave Absorption and Molecular Structure in Liquids. XII. Critical Wavelengths and Intermolecular Forces in the Tetrahalogenated Methanes

Publisher Website
Google Scholar
Abstract
The dielectric constants and losses of bromotrichloromethane, dibromodichloromethane, tribromochloromethane, dibromodifluoromethane, tribromofluoromethane, and trichlorofluoromethane, and of two solutions of trichlorofluoromethane in carbon tetrachloride have been measured at wavelengths of 1.24, 3.22, and 10.0 cm at temperatures between 0 and 60°. The arc plots constructed from these data and the measured static dielectric constants have been used to obtain the optical dielectric constants and the critical wavelengths at which the loss is a maximum. The optical and the static dielectric constants have been used to calculate, by means of the Onsager equation, the values of the small molecular dipole moments, which are in excellent agreement with such values as have been previously determined from vapor measurements. For five of the six molecules studied, the critical wavelengths, which are proportional to the molecular relaxation times for these liquids of low dielectric constant, are roughly consistent with the intermolecular attractive forces as evidenced by the boiling points, polarizabilities, and viscosities of the liquids. The departure of the tribromofluoromethane molecule from spherical form is sufficiently great to account for its larger critical wavelength. The internal or microscopic viscosities hindering molecular rotation in the liquids are much smaller than the measured macroscopic viscosities.

This publication has 14 references indexed in Scilit: