Experimental and theoretical investigations on the structure of the lead–vanadate–tellurate unconventional glasses

Abstract

In this paper, we have examined and analyzed the effects of systematic lead ion intercalations on vanadate–tellurate glasses with interesting results. Glass formation and structural properties of the lead–vanadate–tellurate glasses of compositions xPbO∙(100 − x)[6TeO 2·4V 2O 5], x = 0–100 mol%, are reported for the first time. Influence of lead ions on structural behavior in vanadate–tellurate glasses has been investigated using infrared spectroscopy and DFT calculations. The presented observations in these mechanisms show that the lead ions have an affinity pronounced towards [TeO 3] structural units yielding the deformation of the Te–O–Te linkages and pursuant to the intercalation of [PbO n] entities in the [TeO 4] chain network. On the other hand, lead ions rest between vanadate chains and now directly interact with the oxygen of the V=O bond yielding the elongation of this bond. The role of the lead ions depends on the type of ionic (in the vicinity of the tellurium atoms) or covalent (in the vicinity of the vanadium atoms) bond between lead and oxygen. We propose a possible structural model of building blocks for the formation of continuous random 50PbO·50[6TeO 2·4V 2O 5] glass network. Comparing the theoretical and experimental IR spectral characteristic features, we conclude that the performance of the method/basis sets used on the prediction of the structural data and vibrational modes is good.