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Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions
The polymorphic relationships of the pure rare-earth oxides have been reinvestigated using X-ray diffraction methods for identification of phases. The oxides of the trivalent rare earth ions crystallize in three different types: A, B, and C. Each oxide has only one truly stable polymorph: La(2)O(3),...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
[Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology
1960
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5287085/ https://www.ncbi.nlm.nih.gov/pubmed/32196170 http://dx.doi.org/10.6028/jres.064A.030 |
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author | Roth, R. S. Schneider, S. J. |
author_facet | Roth, R. S. Schneider, S. J. |
author_sort | Roth, R. S. |
collection | PubMed |
description | The polymorphic relationships of the pure rare-earth oxides have been reinvestigated using X-ray diffraction methods for identification of phases. The oxides of the trivalent rare earth ions crystallize in three different types: A, B, and C. Each oxide has only one truly stable polymorph: La(2)O(3), Ce(2)O(3), Pr(2)O(3), and Nd(2)O(3) belong to the A type; Sm(2)O(3), Eu(2)O(3), and Gd(2)O(3) to the B type; Tb(2)O(3), Dy(2)O(3), Ho(2)O(3), Er(2)O(3), Tm(2)O(3), Yb(2)O(3), and Lu(2)O(3) to the C type. In addition Nd(2)O(3), Sm(2)O(3), Eu(2)O(3), and Gd(2)O(3) have low-temperature, apparently metastable, C-type polymorphs. The low-temperature form inverts irreversibly to the stable form at increasingly higher temperatures for decreasing cation radius. |
format | Online Article Text |
id | pubmed-5287085 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1960 |
publisher | [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology |
record_format | MEDLINE/PubMed |
spelling | pubmed-52870852020-03-18 Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions Roth, R. S. Schneider, S. J. J Res Natl Bur Stand A Phys Chem Article The polymorphic relationships of the pure rare-earth oxides have been reinvestigated using X-ray diffraction methods for identification of phases. The oxides of the trivalent rare earth ions crystallize in three different types: A, B, and C. Each oxide has only one truly stable polymorph: La(2)O(3), Ce(2)O(3), Pr(2)O(3), and Nd(2)O(3) belong to the A type; Sm(2)O(3), Eu(2)O(3), and Gd(2)O(3) to the B type; Tb(2)O(3), Dy(2)O(3), Ho(2)O(3), Er(2)O(3), Tm(2)O(3), Yb(2)O(3), and Lu(2)O(3) to the C type. In addition Nd(2)O(3), Sm(2)O(3), Eu(2)O(3), and Gd(2)O(3) have low-temperature, apparently metastable, C-type polymorphs. The low-temperature form inverts irreversibly to the stable form at increasingly higher temperatures for decreasing cation radius. [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology 1960 1960-08-01 /pmc/articles/PMC5287085/ /pubmed/32196170 http://dx.doi.org/10.6028/jres.064A.030 Text en https://creativecommons.org/publicdomain/zero/1.0/ The Journal of Research of the National Bureau of Standards Section A is a publication of the U.S. Government. The papers are in the public domain and are not subject to copyright in the United States. Articles from J Res may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright. |
spellingShingle | Article Roth, R. S. Schneider, S. J. Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title | Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title_full | Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title_fullStr | Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title_full_unstemmed | Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title_short | Phase Equilibria in Systems Involving the Rare-Earth Oxides. Part I. Polymorphism of the Oxides of the Trivalent Rare-Earth Ions |
title_sort | phase equilibria in systems involving the rare-earth oxides. part i. polymorphism of the oxides of the trivalent rare-earth ions |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5287085/ https://www.ncbi.nlm.nih.gov/pubmed/32196170 http://dx.doi.org/10.6028/jres.064A.030 |
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