Comparative study of the short-range structure of α-V 2 O 5 , α-TeO 2 and x V 2 O 5 –(100 − x )TeO 2 glasses using X-ray diffraction, Rietveld analysis and reverse Monte Carlo simulations

Vanadium–tellurite glasses, tetragonal TeO 2 and orthorhombic V 2 O 5 crystalline samples were characterized for their atomic structure properties by synchrotron X-ray diffraction, pair distribution function analysis, reverse Monte Carlo simulations (RMC) and Rietveld analysis. The pair correlation function, G ( r ), of V 2 O 5 shows the first peak at 1.61 Å. G ( r ) of TeO 2 shows three peaks at 1.57, 2.13 and 2.88 Å due to Te–O linkages of three different lengths, whereas the Te–Te atomic pair correlation shows a peak at 3.85 Å. The average coordination number of V with O in crystalline V 2 O 5 is 4.39 while that of Te with O in crystalline TeO 2 is 3.71. G ( r ) of the vanadium tellurite glass shows the first peak at 1.90 Å due to overlapping Te–O and V–O atomic pair correlations. The RMC analysis on diffraction data of glasses found that the V–O coordination number is in the range 5.27–5.59 and the Te–O coordination number is 5.39–5.67. However, it is found that these coordination numbers cannot be clearly defined due to short-range disorder.