Preparation and electron microscopy of intermediate phases in the interval Ce/sub 7/O/sub 12/-Ce/sub 1/O/sub 1/O/sub 20/

Journal Article · Mon Jul 15 00:00:00 EDT 1985 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(85)90213-0· OSTI ID:5189894

Knappe, P; Eyring, L

Crystals of CeO/sub 2/, grown from a flux of sodium tetraborate, were reduced in dry hydrogen to compositions in the interval CeO/sub 1/ /sub 714/-CeO/sub 1/ /sub 818/. Selected compositions were studied using a high-resolution electron microscope. The phase CeO/sub 1/ /sub 714/ (Ce/sub 7/O/sub 12/) was confirmed to have the same unit cell as does Pr/sub 7/O/sub 12/ and Tb/sub 7/O/sub 12/. CeO/sub 1/ /sub 818/(Ce/sub 11/O/sub 20/) was found to be isostructural with Tb/sub 11/O/sub 20/. Two new phases in the interval were established unequivocally. One of them, probably Ce/sub 19/O/sub 34/, is triclinic with a = 6.627, b = 11.478, c = 10.123, ..cap alpha.. = 100.9, ..beta.. = 90.0 and ..gamma.. = 95.5, has not previously been observed in any rare earth oxide system. Another, Ce/sub 62/O/sub 112/, appears to be isomorphous with Tb/sub 62/O/sub 112/. The two intermediate phases previously reported in this interval, Ce/sub 9/O/sub 16/ and Ce/sub 10/O/sub 18/, were not observed, nor was Ce/sub 12/O/sub 22/. Diffraction evidence also points to three additional phases in the interval not previously seen. 20 references, 9 figures, 2 tables.

• Research Organization: Arizona State Univ., Tempe
• OSTI ID: 5189894
• Journal Information: J. Solid State Chem.; (United States), Vol. 58:15
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
ACTIVATION ANALYSIS
ELECTRON DIFFRACTION
ELECTRON MICROSCOPES
EXPERIMENTAL DATA
LATTICE PARAMETERS
MONOCRYSTALS
NEUTRON REACTIONS
SPACE GROUPS
BARYON REACTIONS
CERIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTALS
DATA
DIFFRACTION
HADRON REACTIONS
INFORMATION
MICROSCOPES
MICROSCOPY
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SCATTERING
360201* - Ceramics
Cermets
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360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies