Potassium Disorder in the Defect Pyrochlore KSbTeO6: A Neutron Diffraction Study

Crystals

María Teresa Fernández-Díaz¹  Xabier Turrillas²  José Antonio Alonso³  Sergio Mayer⁴  Horacio Falcón⁴ 

[1] Institut Laue Langevin, BP 156X, F-38042 Grenoble, France;Institut de Ciència de Materials de Barcelona, Consejo Superior de Investigaciones Científicas, Bellaterra, E-08193 Barcelona, Spain;Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas., Cantoblanco, E-28049 Madrid, Spain;Nanotech (Centro de Investigación en Nanociencia y Nanotecnología), Universidad Tecnológica Nacional-Facultad Regional Córdoba, 5016 Córdoba, Argentina;

关键词: pyrochlores;    AB2O6;    ASbTeO6;    neutron powder diffraction;    ionic diffusion;   

DOI  :  10.3390/cryst7010024

来源: DOAJ

【 摘 要 】

KSbTeO6 defect pyrochlore has been prepared from K2C2O4, Sb2O3, and 15% excess TeO2 by solid-state reaction at 850 °C. Direct methods implemented in the software EXPO2013 allowed establishing the basic structural framework. This was followed by a combined Rietveld refinement from X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) data, which unveiled additional structural features. KSbTeO6 is cubic, a = 10.1226(7) Å, space group F d3 ¯m, Z = 8 and it is made of a mainly covalent framework of corner-sharing (Sb,Te)O6 octahedra, with weakly bonded K+ ions located within large cages. The large K-O distances, 3.05(3)–3.07(3) Å, and quite large anisotropic atomic displacement parameters account for the easiness of K+ exchange for other cations of technological importance.

【 授权许可】

Unknown