Toward a Unified Approach to the Crystal Chemistry of Aurivillius-Type Compounds: II. Bi7Ti4NbO21, a Case Study
✍ Scribed by Ph. Boullay; G. Trolliard; D. Mercurio; J.M. Perez-Mato; L. Elcoro
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 395 KB
- Volume
- 164
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
In part I of this paper, a generalized structural model of Aurivillius-type compounds has been presented using a 4D superspace group analysis where Aurivillius structures are considered as cation-deficient perovskites with the general formula AB 1Àx O 3 . Being essentially composition independent, the model is valid for any Aurivillius-type compounds where x is the only composition-dependent parameter. For any composition, the conventional space groups can be easily derived from a unique superspace group. In this second part, a practical example of a structural refinement using the superspace approach is presented for the compound Bi 7 Ti 4 NbO 21 and compared with a conventional 3D refinement. Similarities with other compositionally flexible systems are discussed. # 2002 Elsevier Science (USA)