title: Xenon hexafluoride: structural crystallography of tetrameric phases.
abstract: Three crystalline phases of xenon hexafluoride are based on tetrameric association of XeF(5)(+) and F(-) ions into eight-membered rings. Phase I (monoclinic, 8 XeF(6) units per cell) transforms at approximately 10 degrees C to phase II (orthorhombic, 16 XeF(6) units per cell), which in turn transforms at approximately -25 degrees C to phase 111 (monoclinic, 64 XeF(6) units per doubly primitive cell). The transformation from phase I to phase II requires gross reorientation of half of the tetramers in the structure. The transformation from phase II to phase III involves only an ordering of right-handed and left-handed configurations.
authors.forename: R D
authors.initials: RD
authors.lastname: Burbank
authors.forename: G R
authors.initials: GR
authors.lastname: Jones