Nature of the Transition in Carbon Tetrabromide

Abstract

MANY transitions in solids have in the past been regarded as being due to, or accompanied by, the onset of ionic or molecular rotation. There is, however, little convincing evidence that ions or molecules can rotate freely in crystal lattices. The balance of available data is against this interpretation of transitions, though it is clear from studies of the dielectric constant that, at many transitions in molecular solids with polar molecules, the molecules acquire much greater orientational freedom on passing into the high-temperature form.