Acta Crystallographica Section B

Structural Science

Volume 64, Part 3 (June 2008)

research papers

Acta Cryst. (2008). B64, 281-286 [ doi:10.1107/S0108768108005739 ]

Structural analysis of perovskite LaCr_1 - xNi_xO₃ by Rietveld refinement of X-ray powder diffraction data

J. Yang

Abstract: The crystal structure of perovskite LaCr_1 - xNi_xO₃ (0 [less-than or equal to] x 1.0) has been systematically investigated by analyzing X-ray powder-diffraction data taken at room temperature. Rietveld refinement has confirmed the structural evolution from the orthorhombic phase (Pbnm, Z = 4) to the two-phase (the orthorhombic and the rhombohedral phases) region around x = 0.7, then to the rhombohedral ( $R\bar 3c$ , Z = 2) phase for 0.8 [less-than or equal to] x 1.0. The lattice parameters are also obtained in the refinement process. The results are discussed in terms of reduced Cr/Ni-O bond length with increasing Ni-doping level, leading to an increased tolerance factor caused by the substitution of smaller Ni³⁺ ( $R_{\rm Ni^{3 + } }$ = 0.60 Å, six-coordinate) ions for larger Cr³⁺ ( $R_{\rm Cr^{3 + } }$ = 0.615 Å, six-coordinate) ions.

Keywords: ceramics; perovskite; X-ray powder diffraction.


	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCrO3sup2.rtv ] Contains datablock LaCrO3

	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCr0.7Ni0.3O3sup3.rtv ] Contains datablock LaCr0.7Ni0.3O3

	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCr0.4Ni0.6O3sup4.rtv ] Contains datablock LaCr0.4Ni0.6O3

	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCr0.3Ni0.7O3sup5.rtv ] Contains datablock LaCr0.3Ni0.7O3

	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCr0.2Ni0.8O3sup6.rtv ] Contains datablock LaCr0.2Ni0.8O3

	Rietveld powder data file (CIF format) (91.2 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaCr0.1Ni0.9O3sup7.rtv ] Contains datablock LaCr0.1Ni0.9O3

	Rietveld powder data file (CIF format) (91.1 kbytes) [ doi:10.1107/S0108768108005739/bp5009LaNiO3sup8.rtv ] Contains datablock LaNiO3

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