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1997 | 91 | 3 | 563-568
Article title

Application of Bond Valence Model to Stability of RE Oxycompounds

Content
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Languages of publication
EN
Abstracts
EN
The bond valence model was used to study the stability of the non-stoichiometric LaO_{1-x}F_{1+2x} phases, the solid solubility in the (La_{1-x}Gd_{x}) OCl system and the phase transformation in the REOCl (RE^{3+}=La^{3+} -Nd^{3+}, Sm^{3+}-Gd^{3+}, Ho^{3+}, and Y^{3+}) series. The stability of the non-stoichiometric LaO_{1-x}F_{1+2x} (0 ≤ x ≤ 0.3) phase decreases with increasing excess fluoride. The global instability index values close to 0.2 indicate the instability of the non-stoichiometric phase. The relative stability of the (La_{1-x}Gd_{x})OCl (0 ≤ x ≤ 1.0) solid solutions achieved its minimum in the middle of the series. However, the X-ray powder diffraction results indicated complete solid solubility in the whole (La_{1-x}Gd_{x})OCl series and no phase separation was observed. The bond valence model was used to explain the structural transformation from the tetragonal oxychlorides, REOCl (RE = La-Er, and Y), to hexagonal beyond ErOCl. The calculated global instability index values did not show any clear trend across the REOCl series probably due to the inaccuracies and incoherencies in the original structural data.
Keywords
EN
Publisher

Year
Volume
91
Issue
3
Pages
563-568
Physical description
Dates
published
1997-03
received
1996-06-24
Contributors
author
  • University of Turku, Department of Chemistry, FIN-20014 Turku, Finland
author
  • University of Turku, Department of Chemistry, FIN-20014 Turku, Finland
  • University of Turku, Department of Chemistry, FIN-20014 Turku, Finland
author
  • Åbo Akademi University, Department of Physical Chemistry, FIN-20500 Turku, Finland
author
  • University of Turku, Department of Chemistry, FIN-20014 Turku, Finland
References
Document Type
Publication order reference
Identifiers
YADDA identifier
bwmeta1.element.bwnjournal-article-appv91z308kz
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