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1 Polish Journal of Chemistry

1 2005

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Some Properties of Sodium Tungsten Bronzes as a Function of Sodium Concentration

El-Sayed A., Mousa S.

Polish Journal of Chemistry

2005

Vol. 79 / nr 7

1135-1142

Sodium tungsten bronzes, NaXWO3 have been prepared ranging in composition from x = 0.25 to 0.85 by solid state reaction at 850°C in argon atmosphere. X-ray diffraction and IR absorption spectra were used to characterize the structure of the product samples. It was found two distinct phases in the range from x = 0.25 to 0.85, tetragonal and cubic structure. The reflectance measurements in the range from 300 to 780 nm have been performed by diffuse reflection method. The reflectivity increased with sodium concentration and it was found above 70% for the sample with higher sodium content (x = 0.85). The electrical conductivity (_) has been measured as a function of sodium concentration and temperature from 300 to 550 K. The conductivity was found to increase with increasing sodium concentration and decrease with temperature for the prepared samples.