Polar Distortions in ReF7 and IF7

Abstract

The deflection of molecular beams of ReF₇ and IF₇ by inhomogeneous electric fields has been studied as a function of temperature. Polar components were readily observed in molecular beams of ReF₇, and their intensity increased as the temperature was lowered. A similar effect was just observable for IF₇ at the lowest temperatures attainable. These observations show that the heptafluorides do not have rigid polar structures, but they are compatible with nonrigid distorted geometries for ReF₇ and IF₇.