STRUCTURE-H HYDRATE - A SINGLE-CRYSTAL DIFFRACTION STUDY OF THYLPENTANE-CENTER-DOT-5(XE,H2S)CENTER-DOT-34H(2)O

Although Structure H hydrate has been studied intensively for a number of years, its detailed crystal structure has remained unknown. Single crystal X-ray diffraction was used to determine the structure of 2,2- dimethylpentane . 5(Xe, H2S). 34H(2)O hydrate. The hexagonal unit cell , space group P6/mmm with z=1, has the following parameters: a=12.212( 2), c=10.143(2) Angstrom (t=-100 degrees C). Cage geometries and fract ional coordinates for the atoms are presented and discussed. Structure H hydrate is only the third hydrate type for which a large number of molecules are suitable as guests.