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Crystal structures of N2O to 12 GPa by x‐ray diffraction
Journal of Chemical Physics (1991)
  • R. L. Mills, Los Alamos National Laboratory
  • Bart Olinger, Los Alamos National Laboratory
  • D. T. Cromer, Los Alamos National Laboratory
  • Richard Alan Lesar, Los Alamos National Laboratory
The structures and phase transitions of N2O were studied by powder x‐ray diffraction in a tungsten–carbide anvil device from about 100 to 300 K and 2 to 12 GPa. Two solid phases, α‐N2O and β‐N2O, were observed. The α pattern is consistent with the known low‐pressure low‐temperature ordered cubic form, space group Pa3, up to 4.8 GPa where transition to a new β solid occurs. From refinements using photographic x‐ray intensities, the β‐N2O structure was determined to be orthorhombic Cmca. There are four molecules in a unit cell with a=4.954 Å, b=4.497 Å, and c=6.201 Å at 5.81 GPa and 298 K. The molecular axes lie parallel to the b c plane and are tipped at an angle of 37.2° to the b axis. Random head‐to‐tail orientation is probable in both solids. The phase diagram and values of the molar volume for N2O are compared with published data for the isoelectronic molecule CO2. Recent theoretical calculations correctly predict the β‐N2O structure.
  • crystal structures,
  • carbon dioxide,
  • phase diagram,
  • phase transititons,
  • powders
Publication Date
Publisher Statement
Copyright 1991 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Citation Information
R. L. Mills, Bart Olinger, D. T. Cromer and Richard Alan Lesar. "Crystal structures of N2O to 12 GPa by x‐ray diffraction" Journal of Chemical Physics Vol. 95 (1991)
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