Crystal structure, spectroscopy and thermodynamic properties of M{sup I}VWO{sub 6}(M{sup I} - Li, Na)

Journal Article · Sun Nov 15 00:00:00 EST 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.08.010· OSTI ID:21372379

Maczka, Miroslaw ^[1]; Smirnova, Nataliya N ^[2]; Macalik, Lucyna ^[1]; Kuznetsova, Nataliya Yu; Letyanina, Irene A ^[2]

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1. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)
2. Nizhny Novgorod State University, Gagarin Prospekt 23/2, 603950 Nizhny Novgorod (Russian Federation)

In the present work lithium (sodium) vanadium tungsten oxides with brannerite structure is refined by the Rietveld method (space group C2/m, Z=2). IR and Raman spectroscopy was used to assign vibrational bands and determine structural particularities. The diffuse reflectance spectra allow to calculate bandgap for M{sup I}VWO{sub 6}(M{sup I} - Li, Na). The temperature dependences of heat capacity have been measured first in the range from 7 to 350 K for these compounds and then between 330 and 640 K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C{sub p}{sup o}(T), enthalpy H{sup o}(T)-H{sup o}(0), entropy S{sup o}(T)-S{sup o}(0) and Gibbs function G{sup o}(T)-H{sup o}(0), for the range from T->0 to 640 K. The differential scanning calorimetry was applied to measure decomposition temperature of compounds under study. - Graphical abstract: Fragment of the structure of Li(Na)VWO{sub 6}.

• OSTI ID: 21372379
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 11; Other Information: DOI: 10.1016/j.jssc.2009.08.010; PII: S0022-4596(09)00390-9; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BRANNERITE
CALORIMETRY
DECOMPOSITION
ENTHALPY
ENTROPY
LITHIUM COMPOUNDS
MONOCLINIC LATTICES
RAMAN SPECTROSCOPY
SODIUM COMPOUNDS
SPACE GROUPS
SPECIFIC HEAT
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TUNGSTEN OXIDES
VANADIUM COMPOUNDS
VIBRATIONAL STATES
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ENERGY LEVELS
EXCITED STATES
LASER SPECTROSCOPY
MATERIALS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
REFRACTORY METAL COMPOUNDS
SCATTERING
SPECTROSCOPY
SYMMETRY GROUPS
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
THORIUM MINERALS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
URANIUM MINERALS