Structural variations of Cr-doped (Y,REE)AlO3 perovskites
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Giuseppe Cruciani
Abstract
The crystal structure of ten different Y, REE (REE: rare earth elements) perovskite-type aluminates, doped with chromium, has been investigated by means of synchrotron powder diffraction in order to assess the crystallographic modifications related to varying the lanthanide ions. The symmetry change from orthorhombic (Y, Yb—Sm) to rhombohedral (Nd and Pr) has been confirmed. The anomalous behaviour of the unit cell parameters (in the Pnma setting, b and c contract while a expands as a function of the ‘lanthanide contraction’) has been clarified on the basis of changes in coordination number of the site containing the Y and lanthanide ion: this varies from approximately eight-fold in Yb-, Er-, Ho-, Y-, and Dy-orthoaluminates to nine-fold (or larger) in Gd-, Eu-, and Sm-orthoaluminates to twelve-fold (as in the archetypal cubic structure) in rhombohedral perovskites (Nd and Pr). The coordination number appears about two units greater in orthoaluminates with respect to the corresponding orthoferrites and an inverse correlation between the average bond distance of the Y, REE site and that of the octahedral Al (and Cr) hosting site has been observed.
© by Oldenbourg Wissenschaftsverlag, München
Articles in the same Issue
- Symmetries of coincidence site lattices of cubic lattices
- About the degree of hydration in potassiumtrisoxalatochromate hydrate
- Structural variations of Cr-doped (Y,REE)AlO3 perovskites
- Structure change of Mn2O3 under high pressure and pressure-induced transition
- To crystal chemistry of compounds of MHgYX (M = Cu, Ag, Y = S, Se, X = Cl, Br, I)
- The crystal structures of solvent-free alkali-metal squarates from powder diffraction data
- PDF from X-ray powder diffraction for nanometer-scale atomic structure analysis of quasicrystalline alloys
- Cu2MnMIVS4 (MIV = Si, Ge, Sn) — analysis of crystal structures and tetrahedra volumes of normal tetrahedral compounds
- Synthesis and crystal structure of a homotrinuclear Ni(II) complex
- Two new mononuclear Ni(II) complexes with reduced ONNO type Schiff base
- The cubic limiting complexes of lattice complexes with trigonal characteristic symmetry
Articles in the same Issue
- Symmetries of coincidence site lattices of cubic lattices
- About the degree of hydration in potassiumtrisoxalatochromate hydrate
- Structural variations of Cr-doped (Y,REE)AlO3 perovskites
- Structure change of Mn2O3 under high pressure and pressure-induced transition
- To crystal chemistry of compounds of MHgYX (M = Cu, Ag, Y = S, Se, X = Cl, Br, I)
- The crystal structures of solvent-free alkali-metal squarates from powder diffraction data
- PDF from X-ray powder diffraction for nanometer-scale atomic structure analysis of quasicrystalline alloys
- Cu2MnMIVS4 (MIV = Si, Ge, Sn) — analysis of crystal structures and tetrahedra volumes of normal tetrahedral compounds
- Synthesis and crystal structure of a homotrinuclear Ni(II) complex
- Two new mononuclear Ni(II) complexes with reduced ONNO type Schiff base
- The cubic limiting complexes of lattice complexes with trigonal characteristic symmetry
