The crystal structure of a nonstoichiometric nasicon
The crystal structure of a nonstoichiometric NASICON prepared from a hydrothermally synthesized precursor phase was solved by means of Xray powder and neutron powder diffraction methods. The NASICON phase is monoclinic with unit cell parameters, from Rietveld refinement of the neutron data, of a = 15.6209(8), b = 9.0326(5), c = 9.2172(5)A, ..beta.. = 123.67(1)A, V = 1082.5A/sup 3/. The space group is C2/c with Z = 4. The structure is essentially that proposed earlier by Hong, but the nonstoichiometry results from replacement of part of the Zr/sup 4 +/ by Na/sup +/. Refinement of site occupancies coupled with the requirement of overall charge balance yields the formula Na /sub 2.88/ (Na /sub 0.32/ Zr /sub 1.68/ )Si /sub 1.84/ P /sub 1.16/ O /sub 11.54/ which also agrees well with analytical data. Only 20% of the Na1 sites are occupied, but 80% of the Na3 sites are filled. This structure provides a framework from which to rationalize the many reports in the literature that NASICON can only be prepared with difficulty by high temperature solid state reactions.
- Research Organization:
- Department of Chemistry, Texas A and M University, College Station, Texas
- OSTI ID:
- 6407209
- Journal Information:
- Mater. Res. Bull.; (United States), Vol. 20:6
- Country of Publication:
- United States
- Language:
- English
Similar Records
Time of flight neutron Rietveld refinement study at elevated temperature on a monoclinic near-stoichiometric NASICON
Crystal Structures, Local Atomic Environments, and Ion Diffusion Mechanisms of Scandium-Substituted Sodium Superionic Conductor (NASICON) Solid Electrolytes
Related Subjects
SILICON COMPOUNDS
CHEMICAL PREPARATION
CRYSTALLOGRAPHY
SODIUM COMPOUNDS
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIFFRACTION
HEAT TREATMENTS
OXYGEN COMPOUNDS
PHASE STUDIES
PHOSPHORUS COMPOUNDS
SOLID STATE PHYSICS
ZIRCONIUM COMPOUNDS
ALKALI METAL COMPOUNDS
COHERENT SCATTERING
PHASE TRANSFORMATIONS
PHYSICS
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360602 - Other Materials- Structure & Phase Studies