Structural characterization of a new high-pressure phase of GaAsO4

As in SiO2 which, at high pressures, undergoes the α‐quartz → stishovite transition, GaAsO4 transforms into a dirutile structure at 9 GPa and 1173 K. In 2002, a new GaAsO4 polymorph was found by quenching the compound from 6 GPa and 1273 K to ambient conditions. The powder diagram was indexed on the...

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Bibliographic Details
Published in:Acta crystallographica. Section B, Structural science Structural science, 2006-12, Vol.62 (6), p.1019-1024
Main Authors: Santamaría-Pérez, David, Haines, Julien, Amador, Ulises, Morán, Emilio, Vegas, Angel
Format: Article
Language:English
Subjects:
Arsenates - chemistry
Chemical compounds
Chemical Sciences
Cold working, work hardening
annealing, quenching, tempering, recovery, and recrystallization
textures
Condensed matter: structure, mechanical and thermal properties
Cristallography
Cross-disciplinary physics: materials science
rheology
Crystal structure
Crystalline state (including molecular motions in solids)
Crystallographic aspects of phase transformations
pressure effects
Crystallography
Crystallography, X-Ray
Exact sciences and technology
galium arsenate
Gallium - chemistry
high pressure
High-pressure and shock-wave effects in solids and liquids
Materials science
Mechanical and acoustical properties of condensed matter
Models, Molecular
Physics
powder diffraction
Pressure
Sensitivity and Specificity
structure determination
Structure of solids and liquids
crystallography
Structure of specific crystalline solids
Treatment of materials and its effects on microstructure and properties
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Summary:As in SiO2 which, at high pressures, undergoes the α‐quartz → stishovite transition, GaAsO4 transforms into a dirutile structure at 9 GPa and 1173 K. In 2002, a new GaAsO4 polymorph was found by quenching the compound from 6 GPa and 1273 K to ambient conditions. The powder diagram was indexed on the basis of a hexagonal cell (a = 8.2033, c = 4.3941 Å, V = 256.08 Å3), but the structure did not correspond to any known structure of other AXO4 compounds. We report here the ab initio crystal structure determination of this hexagonal polymorph from powder data. The new phase is isostructural to β‐MnSb2O6 and it can be described as a lacunary derivative of NiAs with half the octahedral sites being vacant, but it also contains fragments of the rutile‐like structure.
ISSN:0108-7681
2052-5192
1600-5740
2052-5206
DOI:10.1107/S0108768106039760