Sodium niobate NaNb/sub 3/O/sub 8/: a novel lamellar oxide synthesized by soft chemistry

Journal Article · Sun Nov 01 04:00:00 EST 1987 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(87)90157-5· OSTI ID:5572449

Nedjar, R; Borel, M M; LeClaire, A; Raveau, B

The ion-exchange properties of the lamellar protonic niobate HNb/sub 3/O/sub 8/ x H/sub 2/O allowed the hydrate NaNb/sub 3/O/sub 8/ x 2.5H/sub 2/O to be synthesized. The thermolysis of this latter hydrate allowed the oxides NaNb/sub 3/O/sub 8/ x H/sub 2/O and NaNb/sub 3/O/sub 8/ to be prepared. These three compounds, are characterized by an orthorhombic cell whose parameters are closely related to those of KNb/sub 3/O/sub 8/, in agreement with their lamellar character: a = 8.971(9) A; b = 28.84(4) A; c = 3.790(4) A for NaNb/sub 3/O/sub 8/ x 2.5 H/sub 2/O; a = 9.072(10) A; b = 22.34(3) A; c = 3.792(3) A for NaNb/sub 3/O/sub 8/ x H/sub 2/O; a = 8.771(14) A; b = 10.16(2) A; c = 3.784(3) A for NaNb/sub 3/O/sub 8/. The structure of NaNb/sub 3/O/sub 8/ has been studied from X-ray powder data; a structural model has been established which shows that NaNb/sub 3/O/sub 8/ consists of octahedral layers similar to those observed in KNb/sub 3/O/sub 8/; the two structures differ from each other by the relative positions of the layers. The structure of NaNb/sub 3/O/sub 8/ can be deduced from that of KNb/sub 3/O/sub 8/ by a translation of an octahedral layer out of two of c/2. This behavior of potassium and sodium is different from that observed in other lamellar oxides Na/sub 2/Ti/sub 3/O/sub 7/, K/sub x/Ti/sub 2-x/M/sub x/O/sub 4/ and NaMnO/sub 2/-..beta...

• Research Organization: Universite de Caen, France
• OSTI ID: 5572449
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 71:1; ISSN JSSCB
• 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
400201* -- Chemical & Physicochemical Properties
ALKALI METAL COMPOUNDS
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHEMICAL PREPARATION
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DATA
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
EXPERIMENTAL DATA
GRAVIMETRIC ANALYSIS
INFORMATION
IONS
LATTICE PARAMETERS
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NUMERICAL DATA
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
POWDERS
QUANTITATIVE CHEMICAL ANALYSIS
REFRACTORY METAL COMPOUNDS
SCATTERING
SODIUM COMPOUNDS
SYNTHESIS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION