THE ELECTRIC MOMENTS OF SUPPOSEDLY SYMMETRICAL CYCLIC SUBSTANCES

Abstract

The distortion polarizations of polysubstituted benzenes and cyclobutanes which have been examined by the randomly oriented solid pellet technique seem to be lower but never higher than the electronic polarization values derived from bond refractions, and are considered to be more reliable than the latter. In almost all of the supposedly symmetrical substances which have been examined the total solute polarization always exceeds the measured distortion polarization and usually exceeds the calculated MRD. These substances must then be polarized, although the moments which have been determined are not numerically reliable because of solvent effects. Whenever possible the temperature coefficients of these apparent moments have been determined and are usually but not always positive. From these temperature coefficients it is presumed that some substances, like naphthalene, are rigidly dipolar whereas others, like hexachlorobenzene, have activation states which are unsymmetrical and therefore contributory to the moment which actually is measured.