{alpha}- and {beta}-Na{sub 2}UO{sub 4}: Structural and thermochemical relationships
Journal Article
·
· Journal of Solid State Chemistry
- Netherlands Energy Research Foundation ECN, Petten (Netherlands)
- Leiden Univ. (Netherlands)
The crystal structures of {alpha}- and {beta}-Na{sub 2}UO{sub 4} have been determined by neutron powder diffraction. In {alpha}-Na{sub 2}UO{sub 4} edge-shared UO{sub 6} octahedra extend in chains along the c axis. In {beta}-Na{sub 2}UO{sub 4} the UO{sub 6} octahedra share corners with each other to form two-dimensional perovskite layers. The octahedra are tilted around both the b and c axes of the unit cell, {alpha}- and {beta}-Na{sub 2}NpO{sub 4} probably have the same structures. The enthalpy of transition of {alpha}-Na{sub 2}UO{sub 4} to {beta}-Na{sub 2}UO{sub 4} has been determined both by DTA measurements and by calorimetric measurements. The unusually high value obtained can be explained from a structural point of view.
- OSTI ID:
- 75761
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 115; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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