Preparation and crystal structure of K{sub 2}YNb{sub 5}O{sub 15-{delta}}

Journal Article · Wed May 01 04:00:00 EDT 1996 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1996.0180· OSTI ID:501791

Kumada, N; Kinomura, N ^[1]

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1. Yamanashi Univ., Kofu (Japan)

Single crystals of new reduced potassium yttrium niobate, K{sub 2}YNb{sub 5}O{sub 15-{delta}}, were prepared in a H{sub 2} atmosphere at 1200{degrees}C. Potassium yttrium niobate crystallizes in the orthorhombic space group Cmmm with a = 10.316(1), b = 15.257(1), and c = 3.914(1) {Angstrom}, Z = 2, and the final R factors are R = 0.046 and R{sub w} = 0.047 for 1077 unique reflections. The crystal structure is built up by corner-sharing of NbO{sub 6} octahedra and the three-dimensional framework formed by the Nb{sub 5}O{sub 15} units is same as that of the NaNb{sub 6}O{sub 15}F-type structure. The Y{sup 3+} ion is located in a distorted perovskite-like cavity and the K{sup +} ion is in a pentagonal tunnel. Reduced potassium yttrium niobate, K{sub 2}YNb{sub 5}O{sub 15-{delta}}, is oxidized without deterioration in crystallinity at about 450{degrees}C, and the oxidized phase, K{sub 2}YNb{sub 5}O{sub 15}, transforms to the tetragonal tungsten bronze-type structure at 1150{degrees}C.

• OSTI ID: 501791
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 123; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
NIOBATES
ORTHORHOMBIC LATTICES
OXIDATION
PHASE TRANSFORMATIONS
POTASSIUM COMPOUNDS
REDUCTION
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
YTTRIUM COMPOUNDS