Please use this identifier to cite or link to this item:
Title: Intercalation route to complex perovskites AM0.2Ta0.8O2.8N0.2 (A = Sr, Ba; M = Li, Na): neutron diffraction and nuclear magnetic resonance study
Authors: Kim, YI
Paik, Y
Avdeev, M
Keywords: Oxides
Multigroup theory
X-ray diffraction
Neutron diffraction
Nuclear magnetic resonance
Issue Date: 3-Dec-2014
Publisher: American Chemical Society
Citation: Kim, Y.-I., Paik, Y., & Avdeev, M. (2015). Intercalation route to complex perovskites AM0.2Ta0.8O2.8N0.2 (A = Sr, Ba; M = Li, Na): Neutron diffraction and nuclear magnetic resonance study. Crystal Growth & Design, 15(1), 53–61. doi:10.1021/cg500739s
Abstract: Oxynitride-type complex perovskites, AM0.2Ta0.8O2.8N0.2 (A = Sr, Ba; M = Li, Na), were synthesized by the ammonolytic heating of a layered perovskite, A5Ta4O15, with 0.5M2CO3. A Rietveld refinement of the synchrotron X-ray and neutron powder diffraction patterns confirmed the complete structural transformation from a hexagonal layered-perovskite to a three-dimensional perovskite type, as well as the stabilization of alkali cations on the octahedral sites rather than on the dodecahedral sites in the latter. In all four compounds, M+ and Ta5+ were disordered completely despite a charge difference as much as 4. The crystal symmetry of the average structure depended on the size of the dodecahedral cation: simple cubic for BaM0.2Ta0.8O2.8N0.2 and body-centered tetragonal for SrM0.2Ta0.8O2.8N0.2. This trend coincides with the symmetry transition from BaTaO2N (Pm3̅m) to SrTaO2N (I4/mcm). In both SrM0.2Ta0.8O2.8N0.2, nitrogen atoms preferentially occupied the c-axial 4a site of the tetragonal cell. Solid state magic angle spinning nuclear magnetic resonance spectroscopy showed that SrNa0.2Ta0.8O2.8N0.2 and BaNa0.2Ta0.8O2.8N0.2 exhibited marked downfield shifts of 23Na, manifesting an octahedral coordination. On the other hand, the 7Li NMR of SrLi0.2Ta0.8O2.8N0.2 and BaLi0.2Ta0.8O2.8N0.2 indicated a highly symmetrical coordination environment of Li. © 2014 American Chemical Society
ISSN: 1528-7505
Appears in Collections:Journal Articles

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.