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Title: Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction

Abstract

The structural determination of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system is a non-trivial problem because of the close resemblance between the ionic sizes of Ce{sup 4+} and Gd{sup 3+} and between the crystal structures of CeO{sub 2} and Gd{sub 2}O{sub 3}. (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} powder samples with x ranging between 0 and 1 have been synthesized by coprecipitation of mixed oxalates and subsequent thermal decomposition in air at 1200 Degree-Sign C followed by slow cooling. Synchrotron powder X-ray diffraction data were collected and refined by the Rietveld method. Lattice parameters do not follow Vegard's law and no peak splitting has been observed for any composition, meaning that no biphasic regions exist over the whole compositional range. The same hybrid structural model - a proper mixture of the structures of the two pure oxides - was used for the refinements, allowing to account for the data observed. - graphical abstract: Substituting Ce{sup 4+} by Gd{sup 3+}, a gradual transition from the F structure (typical of CeO{sub 2}) to the C structure (typical of Gd{sub 2}O{sub 3}) takes place. The lattice parameters do not follow Vegard's law. Highlights: Black-Right-Pointing-Pointer A structural study of Ce-Gd mixed oxides has been performed. Black-Right-Pointing-Pointermore » In (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} a solid solution forms for 0{<=}x{<=}0.3. Black-Right-Pointing-Pointer For x>0.3 a gradual transition from the C to the F structure is observed. Black-Right-Pointing-Pointer Lattice parameters do not follow Vegard's law.« less

Authors:
 [1];  [1];  [2];  [1];  [3];  [3]
  1. Dipartimento di Chimica e Chimica Industriale, Universita degli Studi di Genova, Via Dodecaneso 31, 16146 Genova (Italy)
  2. (Italy)
  3. Sincrotrone Trieste S.C.p.A., ss 14, km 163, 5, 34149 Basovizza, Trieste (Italy)
Publication Date:
OSTI Identifier:
22012120
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: . 190; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CERIUM IONS; CERIUM OXIDES; CRYSTAL STRUCTURE; GADOLINIUM IONS; GADOLINIUM OXIDES; HYBRIDIZATION; LATTICE PARAMETERS; OXALATES; PEAKS; POWDERS; PYROLYSIS; RARE EARTHS; SOLID SOLUTIONS; STRUCTURAL MODELS; SYNCHROTRONS; VEGARD LAW; X-RAY DIFFRACTION

Citation Formats

Artini, Cristina, E-mail: c.artini@ge.ieni.cnr.it, Costa, Giorgio A., E-mail: costa@chimica.unige.it, CNR-SPIN Genova, Corso Perrone 24, 16152 Genova, Pani, Marcella, E-mail: marcella@chimica.unige.it, Lausi, Andrea, E-mail: andrea.lausi@elettra.trieste.it, and Plaisier, Jasper, E-mail: jasper.plaisier@elettra.trieste.it. Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction. United States: N. p., 2012. Web. doi:10.1016/J.JSSC.2012.01.056.
Artini, Cristina, E-mail: c.artini@ge.ieni.cnr.it, Costa, Giorgio A., E-mail: costa@chimica.unige.it, CNR-SPIN Genova, Corso Perrone 24, 16152 Genova, Pani, Marcella, E-mail: marcella@chimica.unige.it, Lausi, Andrea, E-mail: andrea.lausi@elettra.trieste.it, & Plaisier, Jasper, E-mail: jasper.plaisier@elettra.trieste.it. Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction. United States. doi:10.1016/J.JSSC.2012.01.056.
Artini, Cristina, E-mail: c.artini@ge.ieni.cnr.it, Costa, Giorgio A., E-mail: costa@chimica.unige.it, CNR-SPIN Genova, Corso Perrone 24, 16152 Genova, Pani, Marcella, E-mail: marcella@chimica.unige.it, Lausi, Andrea, E-mail: andrea.lausi@elettra.trieste.it, and Plaisier, Jasper, E-mail: jasper.plaisier@elettra.trieste.it. Fri . "Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction". United States. doi:10.1016/J.JSSC.2012.01.056.
@article{osti_22012120,
title = {Structural characterization of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system by synchrotron X-ray diffraction},
author = {Artini, Cristina, E-mail: c.artini@ge.ieni.cnr.it and Costa, Giorgio A., E-mail: costa@chimica.unige.it and CNR-SPIN Genova, Corso Perrone 24, 16152 Genova and Pani, Marcella, E-mail: marcella@chimica.unige.it and Lausi, Andrea, E-mail: andrea.lausi@elettra.trieste.it and Plaisier, Jasper, E-mail: jasper.plaisier@elettra.trieste.it},
abstractNote = {The structural determination of the CeO{sub 2}/Gd{sub 2}O{sub 3} mixed system is a non-trivial problem because of the close resemblance between the ionic sizes of Ce{sup 4+} and Gd{sup 3+} and between the crystal structures of CeO{sub 2} and Gd{sub 2}O{sub 3}. (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} powder samples with x ranging between 0 and 1 have been synthesized by coprecipitation of mixed oxalates and subsequent thermal decomposition in air at 1200 Degree-Sign C followed by slow cooling. Synchrotron powder X-ray diffraction data were collected and refined by the Rietveld method. Lattice parameters do not follow Vegard's law and no peak splitting has been observed for any composition, meaning that no biphasic regions exist over the whole compositional range. The same hybrid structural model - a proper mixture of the structures of the two pure oxides - was used for the refinements, allowing to account for the data observed. - graphical abstract: Substituting Ce{sup 4+} by Gd{sup 3+}, a gradual transition from the F structure (typical of CeO{sub 2}) to the C structure (typical of Gd{sub 2}O{sub 3}) takes place. The lattice parameters do not follow Vegard's law. Highlights: Black-Right-Pointing-Pointer A structural study of Ce-Gd mixed oxides has been performed. Black-Right-Pointing-Pointer In (Ce{sub 1-x}Gd{sub x})O{sub 2-x/2} a solid solution forms for 0{<=}x{<=}0.3. Black-Right-Pointing-Pointer For x>0.3 a gradual transition from the C to the F structure is observed. Black-Right-Pointing-Pointer Lattice parameters do not follow Vegard's law.},
doi = {10.1016/J.JSSC.2012.01.056},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = . 190,
place = {United States},
year = {2012},
month = {6}
}