The High-Temperature Phases of WO3

High-temperature, high-resolution neutron powder diffraction experiments were performed to investigate the phases of WO3between room temperature and 850°C. Two phases were found and characterized by Rietveld refinements: orthorhombicβ-WO3(Pbcn,a=7.3331(2),b=7.5733(2),c=7.7401(3) Å at 350°C, tilt sys...

Full description

Saved in:
Bibliographic Details
Published in:Journal of solid state chemistry 1999-04, Vol.144 (1), p.209-215
Main Authors: Vogt, Tom, Woodward, Patrick M, Hunter, Brett A
Format: Article
Language:English
Subjects:
Condensed matter: structure, mechanical and thermal properties
Crystalline state (including molecular motions in solids)
Crystallographic aspects of phase transformations
pressure effects
Exact sciences and technology
Inorganic compounds
Physics
Structure of solids and liquids
crystallography
Structure of specific crystalline solids
Water, oxides, hydroxides, peroxides
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:High-temperature, high-resolution neutron powder diffraction experiments were performed to investigate the phases of WO3between room temperature and 850°C. Two phases were found and characterized by Rietveld refinements: orthorhombicβ-WO3(Pbcn,a=7.3331(2),b=7.5733(2),c=7.7401(3) Å at 350°C, tilt systema0b+c−) and tetragonalα-WO3(P4/ncc,a= 5.2759(1),b=5.2759(1),c=7.8462(3) Å at 800°C, tilt systema0a0c−). The sequence of temperature-induced phase transitions in WO3can be rationalized in terms of changes in the octahedral tilt systems and/or displacements of the tungsten out of the center of the WO6octahedron. Above room temperature the two phase transitions are driven by sucessive softening of phonon modes,M3at theα- toβ-transition andR25at theβ- toγ-transition.
ISSN:0022-4596
1095-726X
DOI:10.1006/jssc.1999.8173