Structural chemistry and Raman spectra of niobium oxides

Journal Article · · Chemistry of Materials; (United States)

DOI:https://doi.org/10.1021/cm00013a025· OSTI ID:5206683

Jehng, Jihmirn; Wachs, I E ^[1]

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1. Lehigh Univ., Bethlehem, PA (USA)

A series of niobium oxide reference compounds were investigated by Raman spectroscopy in order to determine the relationship between niobium oxide structures and their corresponding Raman spectra. The assignments of the Raman bands were based on the known niobium oxide structures. The Raman studies indicate that the Raman frequencies strongly depend on the niobium oxide structures. For the slightly distorted octahedral NbO{sub 6} structures (KNbO{sub 3}, NaNbO{sub 3}, and LiNbO{sub 3}), the major Raman frequencies appear in the 500-700-cm{sup {minus}1} region. For the highly distorted octahedral NbO{sub 6} structures (K{sub 8}Nb{sub 6}O{sub 19}, AlNbO{sub 4}, and Nb(HC{sub 2}O{sub 4}){sub 5}), the major Raman frequencies shift from the 500-700- to 850-1000-cm{sup {minus}1} region. The distortions in the niobium oxide compounds are caused by the corner- or edge-shared NbO{sub 6} octahedra. Both slightly distorted and highly distorted octahedral NbO{sub 6} sites coexist in the KCa{sub 2}Na{sub n-3}Nb{sub n}O{sub 3n+1}, n = 3-5, layered compounds. Most of the niobium oxide compounds possess an octahedrally coordinated NbO{sub 6} structure with different extents of distortion, and only a few rare-earth ANbO{sub 4} (A = Y, Yb, Sm, and La) compounds possess a tetrahedrally coordinated NbO{sub 4} structure.

• OSTI ID: 5206683
• Journal Information: Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 3:1; ISSN CMATE; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
CHALCOGENIDES
DATA
EXPERIMENTAL DATA
INFORMATION
MEASURING METHODS
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
RAMAN SPECTRA
REFRACTORY METAL COMPOUNDS
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS