Structure and luminescence of the. cap alpha. -LnNb/sub 3/O/sub 9/-type rare earth niobates

Journal Article · Mon Jul 01 00:00:00 EDT 1985 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(85)90236-1· OSTI ID:5105977

Torardi, C C; Brixner, L H; Foris, C M

..cap alpha..-LnNb/sub 3/O/sub 9/ (Ln = La, Pr, Nd) compounds have been prepared hydrothermally from acidic solutions. In comparison to the previously reported orthorhombic ..beta.. modifications, ..cap alpha..-LnNb/sub 3/O/sub 9/ compounds are monoclinic. The structure of ..cap alpha..-PrNb/sub 3/O/sub 9/ was determined with a = 5.3784(6), b = 7.602(2), c = 16.344(2) A, and ..beta.. = 92.21(1)/sup 0/, space group Ps/sub 1//c. It is built of double and single chains of cornershared NbO/sub 6/ octahedra extended along the b axis. Praseodymium atoms reside in tunnels along the b axis and are in eight-coordination with oxygen. All ..cap alpha..-LnNb/sub 3/O/sub 9/ compounds can be irreversibly converted to the ..beta.. modification by heating in air to 1200/sup 0/C. The X-ray excited luminescence of Sm-, Eu-, Tb-, and Dy-doped ..cap alpha..-LaNb/sub 3/O/sub 9/ is also reported. 11 references, 3 figures, 5 tables.

• Research Organization: E.I. du Pont de Nemours and Co., Wilmington, DE
• OSTI ID: 5105977
• Journal Information: J. Solid State Chem.; (United States), Vol. 58:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM COMPOUNDS
CRYSTALLOGRAPHY
X-RAY EMISSION ANALYSIS
NEODYMIUM COMPOUNDS
NIOBATES
PRASEODYMIUM COMPOUNDS
BOND ANGLE
BOND LENGTHS
CHEMICAL PREPARATION
DOPED MATERIALS
EXPERIMENTAL DATA
LATTICE PARAMETERS
LUMINESCENCE
MONOCLINIC LATTICES
POWDERS
SPACE GROUPS
STRUCTURAL CHEMICAL ANALYSIS
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
CHEMICAL ANALYSIS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
DIMENSIONS
INFORMATION
LENGTH
MATERIALS
NIOBIUM COMPOUNDS
NONDESTRUCTIVE ANALYSIS
NUMERICAL DATA
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication