Effect of temperature on cation disorder in ABi2Nb2O9 (A=Sr, Ba)
- 1 January 1999
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry
- Vol. 9 (2) , 541-544
- https://doi.org/10.1039/a806760k
Abstract
The influence of thermal annealing on cation disorder in ABi 2 Nb 2 O 9 (A=Sr, Ba) has been studied using synchrotron powder X-ray diffraction methods. BaBi 2 Nb 2 O 9 adopts a tetragonal (I4 1 /mmm) structure, whilst SrBi 2 Nb 2 O 9 is orthorhombic, space group A2 1 am, irrespective of the annealing conditions. In both complexes the A-type cations, Sr and Ba, are disordered over the perovskite and Bi 2 O 2 layers. Quenching the samples from high temperature results in a slight increase in both the cell volume and the degree of disorder, the extent of disorder being greater in the Ba complex. Variable temperature diffraction studies are also reported.Keywords
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