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Title: Structural characterization and polymorphism of R[sub 2]BaNiO[sub 5] (R = Nd, Gd, Dy, Y, Ho, Er, Tm, Yb) studied by neutron diffraction

Abstract

The family of compounds R[sub 2]BaNiO[sub 5] (R = Nd, Dy, Y, Ho, Er, Tm, Yb) has been studied by neutron powder diffraction at room temperature. All of them present orthorhombic symmetry (space group Immm, Z = 2). The main feature of these materials is the existence of one-dimensional chains of vertex-sharing NiO[sub 6] octahedra along the a-axis. The present research has revealed the effect of the size of the rare earth ions on the structural parameters, which plays a role nearly equivalent to a hydrostatic [open quotes]chemical pressure[close quotes] in the geometric distortion of the structure. The volume of the Ni and Ba polyhedra varies linearly vs the ionic radius of the rare earth. The overall agreement between the valence bond sums and formal charges is very poor. This fact indicates that the present structure is under very high internal stress and may be metastable. The authors speculate that there may exist a dimorphism in the other members of this family of oxides, similar to that already found for the Tm, Yb, and Lu compounds. 38 refs., 8 figs., 2 tabs.

Authors:
;  [1];  [2];  [3]; ;  [4]
  1. (Institut Laue-Langevin, Grenoble (France))
  2. (Universidad Autonoma de Madrid (Spain))
  3. (Instituto de Ciencia de Materiales de Madrid (Spain))
  4. (Universidad Complutense, Madrid (Spain))
Publication Date:
OSTI Identifier:
6050598
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry; (United States)
Additional Journal Information:
Journal Volume: 103:2; Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BARIUM OXIDES; CRYSTAL STRUCTURE; NICKEL OXIDES; RARE EARTH COMPOUNDS; YTTRIUM OXIDES; DYSPROSIUM OXIDES; ERBIUM OXIDES; GADOLINIUM OXIDES; HOLMIUM OXIDES; IONS; NEODYMIUM OXIDES; NEUTRON DIFFRACTION; ORTHORHOMBIC LATTICES; SYMMETRY; THULIUM OXIDES; VALENCE; YTTERBIUM OXIDES; ALKALINE EARTH METAL COMPOUNDS; BARIUM COMPOUNDS; CHALCOGENIDES; CHARGED PARTICLES; COHERENT SCATTERING; CRYSTAL LATTICES; DIFFRACTION; DYSPROSIUM COMPOUNDS; ERBIUM COMPOUNDS; GADOLINIUM COMPOUNDS; HOLMIUM COMPOUNDS; NEODYMIUM COMPOUNDS; NICKEL COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; SCATTERING; THULIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; YTTERBIUM COMPOUNDS; YTTRIUM COMPOUNDS; 360202* - Ceramics, Cermets, & Refractories- Structure & Phase Studies

Citation Formats

Garcia-Matres, E., Rodriguez-Carvajal, J., Martinez, J.L., Alonso, J.A., Salinas-Sanchez, A., and Saez-Puche, R.. Structural characterization and polymorphism of R[sub 2]BaNiO[sub 5] (R = Nd, Gd, Dy, Y, Ho, Er, Tm, Yb) studied by neutron diffraction. United States: N. p., 1993. Web. doi:10.1006/jssc.1993.1107.
Garcia-Matres, E., Rodriguez-Carvajal, J., Martinez, J.L., Alonso, J.A., Salinas-Sanchez, A., & Saez-Puche, R.. Structural characterization and polymorphism of R[sub 2]BaNiO[sub 5] (R = Nd, Gd, Dy, Y, Ho, Er, Tm, Yb) studied by neutron diffraction. United States. doi:10.1006/jssc.1993.1107.
Garcia-Matres, E., Rodriguez-Carvajal, J., Martinez, J.L., Alonso, J.A., Salinas-Sanchez, A., and Saez-Puche, R.. Thu . "Structural characterization and polymorphism of R[sub 2]BaNiO[sub 5] (R = Nd, Gd, Dy, Y, Ho, Er, Tm, Yb) studied by neutron diffraction". United States. doi:10.1006/jssc.1993.1107.
@article{osti_6050598,
title = {Structural characterization and polymorphism of R[sub 2]BaNiO[sub 5] (R = Nd, Gd, Dy, Y, Ho, Er, Tm, Yb) studied by neutron diffraction},
author = {Garcia-Matres, E. and Rodriguez-Carvajal, J. and Martinez, J.L. and Alonso, J.A. and Salinas-Sanchez, A. and Saez-Puche, R.},
abstractNote = {The family of compounds R[sub 2]BaNiO[sub 5] (R = Nd, Dy, Y, Ho, Er, Tm, Yb) has been studied by neutron powder diffraction at room temperature. All of them present orthorhombic symmetry (space group Immm, Z = 2). The main feature of these materials is the existence of one-dimensional chains of vertex-sharing NiO[sub 6] octahedra along the a-axis. The present research has revealed the effect of the size of the rare earth ions on the structural parameters, which plays a role nearly equivalent to a hydrostatic [open quotes]chemical pressure[close quotes] in the geometric distortion of the structure. The volume of the Ni and Ba polyhedra varies linearly vs the ionic radius of the rare earth. The overall agreement between the valence bond sums and formal charges is very poor. This fact indicates that the present structure is under very high internal stress and may be metastable. The authors speculate that there may exist a dimorphism in the other members of this family of oxides, similar to that already found for the Tm, Yb, and Lu compounds. 38 refs., 8 figs., 2 tabs.},
doi = {10.1006/jssc.1993.1107},
journal = {Journal of Solid State Chemistry; (United States)},
issn = {0022-4596},
number = ,
volume = 103:2,
place = {United States},
year = {1993},
month = {4}
}