Crystal structure and thermodynamic properties of potassium antimony tungsten oxide

• Published in: Thermochimica acta Vol. 499; no. 1; pp. 155 - 159
• Main Authors: Knyazev, Aleksandr V., Tananaev, Ivan G., Kuznetsova, Nataliya Yu, Smirnova, Nataliya N., Letyanina, Irene A., Ladenkov, Igor V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20-02-2010
• Subjects: Antimony; Entropy; Heat capacity; Potassium; Potassium antimony tungsten oxide; Pyrochlore; Specific heat; Thermal expansion; Thermodynamic functions; Tungsten oxides; X-ray diffraction; Pyrochlore; Heat capacity; X-ray diffraction; Thermodynamic functions; Potassium antimony tungsten oxide
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2009.12.002

In the present work potassium antimony tungsten oxide with pyrochlore structure is refined by the Rietveld method (space group
Fd3
m,
Z
=
8). The temperature dependences of heat capacity have been measured for the first time in the range from 7 to 370
K for this compound. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity
C
p
°
(
T
)
, enthalpy
H°(
T)
−
H°(0), entropy
S°(
T)
−
S°(0) and Gibbs function
G°(
T)
−
H°(0), for the range from
T
→
0 to 370
K. The differential scanning calorimetry was applied to measure the incongruent melting temperature of compound under study. The high-temperature X-ray diffraction was used for the determining thermal expansion coefficients.