S0007

Disordered Structure of XENON HEXAFLUORlDE at 19(. Paul A. Agron, Oak Ridge National Laboratory, Oak Ridge, TN 37831

The properties of gaseous Xenon Hexafluoride has received extensive study and theeoretical treatments which pose some unusual problems. In the present X-ray study at 19( C, the crystal syrrunetry of P21/m is proposed with an asymmetric molecule consisting of a tetramenc group of xenon atoms bridged by a tetramer of fluorine atoms at a somewhat larger Xe-F spacing of ~2.6 Å. Each xenon atom holds 5 additional atoms at a normal Xe-F bond of l.9 _.