Structure and stability of solid Xe(H{sub 2}){sub n}

Journal Article · Sat Mar 14 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4908265· OSTI ID:22415510

Somayazulu, Maddury; Hemley, Russell J. ^[1]; Dera, Przemyslaw ^[2]; Smith, Jesse ^[3]

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1. Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015-1305 (United States)
2. GSECARS, Advanced Photon Source, University of Chicago, Argonne, Illinois 60439 (United States)
3. HPCAT, Advanced Photon Source, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States)

Mixtures of xenon and molecular hydrogen form a series of hexagonal, van der Waals compounds at high pressures and at 300 K. Synchrotron, x-ray, single crystal diffraction studies reveal that below 7.5 GPa, Xe(H{sub 2}){sub 8} crystallizes in a P3{sup -}m1 structure that displays pressure-induced occupancy changes of two pairs of xenon atoms located on the 2c and 2d sites (while the third pair on yet another 2c site remains fully occupied). The occupancy becomes 1 at the P3{sup -}m1 to R3 transition and all the xenon atoms occupy the 3d sites in the high-pressure structure. These pressure-induced changes in occupancy coincide with volume changes that maintain the average Xe:H{sub 2} stoichiometry fixed at 1:8. The synchrotron x-ray diffraction and Raman measurements show that this unique hydrogen-bearing compound that can be synthesized at 4.2 GPa and 300 K, quenched at low temperatures to atmospheric pressure, and retained up to 90 K on subsequent warming.

• OSTI ID: 22415510
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 10 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ATOMS
HYDROGEN
MIXTURES
MONOCRYSTALS
PHASE STABILITY
PHASE STUDIES
PRESSURE DEPENDENCE
RAMAN SPECTROSCOPY
SOLIDS
STOICHIOMETRY
TEMPERATURE DEPENDENCE
VAN DER WAALS FORCES
X-RAY DIFFRACTION
XENON