High-pressure x-ray diffraction study of CeO/sub 2/ to 70 GPa and pressure-induced phase transformation from the fluorite structure

Journal Article · Sat Oct 15 00:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.7755· OSTI ID:6782299

Duclos, S J; Vohra, Y K; Ruoff, A L; Jayaraman, A; Espinosa, G P

The crystal structure of CeO/sub 2/ has been investigated to 70 GPa using energy dispersive x-ray diffraction in a diamond-anvil cell. At 31.5 +- 1.0 GPa the fluorite phase transforms, on loading, to an orthorhombic ..cap alpha..-PbCl/sub 2/-like structure of space group Pnam, with a 7.5% +- 0.7% increase in density. The cubic fluorite phase has a bulk modulus B/sub 0/ = 230 +- 10 GPa with an assumed pressure derivative of B/sub 0//sup '/ = 4.00. The ..cap alpha..-PbCl/sub 2/-type structure seems to be the stable high-pressure phase in the case of the group-IVB, lanthanide, and actinide fluorite-type dioxides, independent of metal-ion size, at reduced volumes less than 0.89 +- 0.01.

• Research Organization: Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853
• OSTI ID: 6782299
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 38:11
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTAL STRUCTURE
ORTHORHOMBIC LATTICES
PRESSURE DEPENDENCE
VERY HIGH PRESSURE
X-RAY DIFFRACTION
CERIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL LATTICES
DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
SCATTERING
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies