Crystal structure of a new high-pressure phase, K{sub 0.82}Mg{sub 1.68}(Cr{sub 2.84}Fe{sub 0.84}Ti{sub 2.11}Zr{sub 0.08})O{sub 12}, with one-dimensional tunnels
- Department of Mechanical and Materials Engineering, EC, Center for Study of Matter at Extreme Conditions (CeSMEC), Florida International University, University Park, Campus Room VH-140, Miami, FL 33199 (United States)
- Institut fuer Mineralogie und Petrographie, Universitaet Innsbruck, Bruno Sander Haus, Innrain 52, A-6020 Innsbruck (Austria)
The crystal structure of a new complex Ti-Cr oxide phase, K{sub 0.82}Mg{sub 1.68}(Cr{sub 2.84}Fe{sub 0.84}Ti{sub 2.11}Zr{sub 0.08})O{sub 12}, synthesized at 13GPa and 1400{sup o}C, has been determined with single-crystal X-ray diffraction. It has a hexagonal symmetry with the space group P6{sub 3}/m and unit-cell parameters a=9.1763(13) and c=2.8790(6)A, V=209.89(8)A3, Z=1. The structure is characterized by the hollandite-type double chains of edge-shared M2 octahedra occupied by trivalent and tetravalent cations (Ti+Cr+Fe+Zr); these double chains are linked to one another through shared octahedral apexes to form a framework structure containing two types of tunnels running parallel to the c-axis. One type of tunnels has a hexagonal cross-section and is occupied by large K{sup +}, whereas the other has a triangular cross-section and is occupied by Mg{sup 2+}. The K{sup +} cation is disordered between two crystallographically equivalent (2a) sites in the tunnels and displays a U33 displacement parameter that is significantly greater than U11. The new high-pressure phase reported in this study possesses many structural features similar to those for the hollandite compounds, making it a candidate for the 1-D fast ionic conductors.
- OSTI ID:
- 20658236
- Journal Information:
- Journal of Solid State Chemistry, Vol. 177, Issue 12; Other Information: DOI: 10.1016/j.jssc.2004.09.030; PII: S0022-4596(04)00511-0; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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