Formation, structure and magnetism of the metastable defect fluorite phases AVO{sub 3.5+x} (A=In, Sc)
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)
- Canadian Neutron Beam Centre, National Research Council Canada, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada)
We report the preparation and stability of ScVO{sub 3.5+x} and the novel phase InVO{sub 3.5+x}. AVO{sub 3.5+x} (A=Sc, In) defect fluorite structures are formed as metastable intermediates during the topotactic oxidation of AVO{sub 3} bixbyites. The oxidation pathway has been studied in detail by means of thermogravimetric/differential thermal analysis and in-situ powder X-ray diffraction. The oxidation of the bixbyite phase follows a topotactic pathway at temperatures between 300 and 400 deg. C in air/carbon dioxide. The range of accessible oxygen stoichiometries for the AVO{sub 3.5+x} structures following this pathway are 0.00{<=}x{<=}0.22. Rietveld refinements against powder X-ray and neutron data revealed that InVO{sub 3.54} and ScVO{sub 3.70} crystallize in the defect fluorite structure in space group Fm-3 m (227) with a=4.9863(5) and 4.9697(3)A, respectively with A{sup 3+}/V{sup 4+} disorder on the (4a) cation site. Powder neutron diffraction experiments indicate clustering of oxide defects in all samples. Bulk magnetic measurements showed the presence of V{sup 4+} and the absence of magnetic ordering at low temperatures. Powder neutron diffraction experiments confirmed the absence of a long range ordered magnetic ground state. - Graphical abstract: Topotactic oxidation of AVO{sub 3} bixbyite to AVO{sub 3.5} defect fluorite structure followed by in-situ powder X-ray diffraction. The upper structural diagram shows a six coordinated (A/V)-O{sub 6} fragment in bixbyite, the lower structure illustrates the same seven-fold coordinated (A/V)-O{sub 7} cubic environment in the defect fluorite structure.
- OSTI ID:
- 21043760
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 180; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
Similar Records
In situ X-ray powder diffraction, synthesis, and magnetic properties of InVO{sub 3}
Oxygen trapping and cation site-splitting in Y(2₋x)PrxO3+δ (0.0≤x<2.0 and δ≤1.0)
Related Subjects
CARBON DIOXIDE
CRYSTAL DEFECTS
CUBIC LATTICES
DIFFERENTIAL THERMAL ANALYSIS
INDIUM COMPOUNDS
MAGNETISM
MAGNETIZATION
NEUTRON DIFFRACTION
OXIDATION
OXIDES
OXYGEN
POWDERS
SCANDIUM COMPOUNDS
SPACE GROUPS
STABILITY
THERMAL GRAVIMETRIC ANALYSIS
VANADIUM COMPOUNDS
VANADIUM IONS
X-RAY DIFFRACTION