Determinations of crystallographic space group and atomic arrangements in oxide-ion-conducting Nd9.33(SiO4)6O2
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Hiroki Okudera
Abstract
In this paper we report single crystal X-ray diffraction study of an oxide-ion-conductor Nd9.33(SiO4)6O2 at 150 K. By detailed examinations of the atomic positions and an electron density distribution, it was clearly shown that Nd9.33(SiO4)6O2 has an apatite structure (space group P63/m) with no symmetry lowering or site-splitting. All oxygens in the hexagonal channel were located at their ideal positions (2a site at 0, 0, ¼) of the apatite structure, while their thermal displacements were highly anisotropic and that in the c-axis direction was more than four-times larger than those in other directions. Cation vacancies were located at the nine-coordinated 4f Nd site. The other Nd site (seven-coordinated 6h site) were basically fully occupied. This full occupation of the 6h Nd site makes potential waves inside the hexagonal channel smooth and transports of oxide-ions in the channel much easier. The distortion of SiO4 tetrahedron was not apparent. Crystallographic data at 150 K: Cell dimensions a = 9.5556(6) Å and c = 7.019(2) Å; F(000) = 852; Z = 1; Dc = 5.779(2) g/cm3.
© 2004 Oldenbourg Wissenschaftsverlag GmbH
Artikel in diesem Heft
- Editorial
- Quantitative comparisons of structures
- TexPat – a program for quantitative analysis of oblique texture electron diffraction patterns
- The system Cu3AsS4–Cu3SbS4 and investigations on normal tetrahedral structures
- Determinations of crystallographic space group and atomic arrangements in oxide-ion-conducting Nd9.33(SiO4)6O2
- Crystal structures of α-quartz homeotypes boron phosphate and boron arsenate: structure-property relationships
- Three polymorphic forms of dipotassium O-phospho-L-serinate hydrates
- Comparative neutron and X-ray study of [PPN][HIr4(CO)9(μ-Ph2PCH2PPh2)]
- Books Received
Artikel in diesem Heft
- Editorial
- Quantitative comparisons of structures
- TexPat – a program for quantitative analysis of oblique texture electron diffraction patterns
- The system Cu3AsS4–Cu3SbS4 and investigations on normal tetrahedral structures
- Determinations of crystallographic space group and atomic arrangements in oxide-ion-conducting Nd9.33(SiO4)6O2
- Crystal structures of α-quartz homeotypes boron phosphate and boron arsenate: structure-property relationships
- Three polymorphic forms of dipotassium O-phospho-L-serinate hydrates
- Comparative neutron and X-ray study of [PPN][HIr4(CO)9(μ-Ph2PCH2PPh2)]
- Books Received
