Crystal chemistry on a lattice: The case of BZN and BZN-related pyrochlores
- Research School of Chemistry, Australian National University, Canberra, A.C.T 0200 (Australia)
- Electronic Materials Research Laboratory, Xian Jiaotong University, Xian, Shaanxi 710049 (China)
This paper uses a diagnostic, highly structured diffuse intensity distribution to investigate the local crystal chemistry of (Bi{sub 1.5}Zn{sub 0.5-} {sub {delta}} )(Zn{sub 0.5}Nb{sub 1.5})O{sub 7-} {sub {delta}} (BZN) as well as Sn{sup 4+} and Ti{sup 4+}, B site substituted, BZN-related pyrochlore phases. The structured diffuse distribution of the B site substituted material is found to be remarkably similar to that observed for BZN itself. In the special case of (Bi{sub 1.5}Zn{sub 0.5})(Ti{sub 1.5}Nb{sub 0.5})O{sub 7} (BZNT), the continuous G{+-}<10l>* type diffuse streaking characteristic of BZN-related pyrochlores has virtually condensed out to give just G{+-}<001>* 'satellite reflections' and a P-centred, close to a superstructure phase of average pyrochlore unit cell dimensions. Bond valence sum considerations are used to investigate the local crystal chemistry of this BZNT phase and to derive a plausible model for this superstructure phase. Monte Carlo modelling is used to confirm the plausibility of the model proposed. The underlying crystal chemistry of BZN and BZN-related pyrochlores is shown to result from strong local Bi/Zn ordering rules and associated large amplitude structural relaxation. - Graphical abstract: A typical <00l> zone axis EDP of of (Bi{sub 1.5}Zn{sub 0.5})(Ti{sub 1.5}Nb{sub 0.5})O{sub 7} (BZNT)
- OSTI ID:
- 20905360
- Journal Information:
- Journal of Solid State Chemistry, Vol. 179, Issue 7; Other Information: DOI: 10.1016/j.jssc.2006.04.017; PII: S0022-4596(06)00224-6; Copyright (c) 2006 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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