Synthesis and characterization of La[sub 3]NbSe[sub 2]O[sub 4]F[sub 2]

Journal Article · Wed Dec 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1380· OSTI ID:7107950

Brennan, T D; Mansuetto, M F; Ibers, J A ^[1]

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1. Northwestern Univ., Evanston, IL (United States)

Crystals of the unusual oxyfluoroselenide La[sub 3]NbSe[sub 2]O[sub 4]F[sub 2] were obtained during the exploration of the quaternary La/Nb/Cu/Se system. Oxygen was extracted from the silica tube, while fluorine was present as a minor impurity in the La powder. The compound crystallizes in space group D[sup 16][sub 2h]-Pnma of the orthorhombic system with four formula units in a cell with dimensions: a = 11.290(4), b = 4.001(1), and c = 18.062(4) [angstrom] (T = 113 K). The structure has been determined by single-crystal X-ray methods. The presence of F in the crystals was confirmed by windowless EDAX measurements. The two F sites were distinguished from the four O sites from a combination of the X-ray refinement and a bond-valence parameter calculation made with the program EUTAX. In the structure the Nb atom is octahedrally coordinated while each of the three independent La atoms is in a tricapped trigonal prism. The Nb atom is bound to one Se atom and five O atoms while the three La sites are coordinated by various combinations of Se, O, and F atoms. The NbO[sub 5]Se octahedra corner share and the LaSe[sub x]O[sub y]F[sub 2] tricapped trigonal prisms face share in the b direction.

• OSTI ID: 7107950
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 107:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CHALCOGENIDES
CHEMICAL PREPARATION
CRYSTAL LATTICES
CRYSTAL STRUCTURE
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LANTHANUM COMPOUNDS
LATTICE PARAMETERS
NIOBIUM COMPOUNDS
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
SELENIUM COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS