The structure of tellurite glass: a combined NMR, neutron diffraction, and X-ray diffraction study

Abstract

Models are presented of sodium tellurite glasses in the composition range (Na20)z-(Te02)1_=, 0.1 < z <0.3.The models combine self-consistently data from three different and complementary sources: sodium-23 nuclear magnetic resonance (NMR), neutron diffraction, and x-ray diffraction. The models were generated using the Reverse Monte Carlo algorithm, modified to include NMR data in addition to diffraction data.The presence in the models of all five tellurite polyhedra consistent with the Te+4 oxidation state were found to be necessary to achieve agreement with the data. The distribution of polyhedra among these types varied from a predominance of highly bridged species at low sodium content, to polyhedra with one or zero bridging oxygen

Alkali environments in tellurite glasses

“…A peak in that arises solely from interatomic distances between atoms of element and can be fitted to determine the area, , and position, , for the peak. Using these parameters, along with the weighting coefficient for in Equation (1), the coordination number, , can be calculated according to (2) where is the Kronecker delta.…”

“…The local structure of alkali M2O-TeO2 glasses (M = Li, Na, and K) has been studied extensively using neutron diffraction [1][2][3][4][5], X-ray diffraction [6,7], EXAFS [7,8], Raman scattering [7,9,10], NMR [2,[11][12][13] and RMC modelling [2,14]. In these studies, particular emphasis was placed on determining the local environment of tellurium and there is a general consensus that the average tellurium coordination number, nTeO, decreases as an oxide modifier is added to the glass network, the change being driven by the bonding requirements of the modifier.…”

Structural investigations of the xTeO2–(1−x)GeO2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1) tellurite glasses: A composition dependent Raman spectroscopic study

“…Currently, there exist a large amount of literature regarding the structure of pure TeO 2 and xM 2 O-(1-x)TeO 2 (M 2 O: alkali oxide, x: mole fraction) glasses with a variety of techniques such as X-ray diffraction [6][7][8], neutron diffraction [8,9], NMR [10][11][12], Mösbauer spectroscopy [13], EXAFS [14], ab initio quantum-mechanical calculations [15,16], molecular orbital calculations [9], Brillouin [17], IR [ 18,19] and Raman scattering [20][21][22][23]. However, a limited number of papers have been focused on binary glassy systems where both components are glassformers participating directly in the formation of the vitreous network.…”

Structural studies of Bi2O3-Nb2O5-TeO2 glasses

“…An RMC model was constructed assuming a pure TeO2 glass composition. A 3000 atom configuration generated with cut-off constraints similar to McLaughlin 30,31 was used to establish the partial Te-Te, Te-O and O-O contributions to S(Q) and D(r) (Fig 3). The RMC simulations demonstrate that the asymmetric peak at 3.5 A in the D(r) comprises overlapping Te-Te and Te-O partial contributions.…”

“…The presence of the lone pair gives rise to useful non-linear optical properties. The oxygen atoms involved in bridging between TeO4 units occur at axial and equatorial positions 31,33 . Adding modifier components to provide glassforming compositions causes disruption of the network with the appearance of TeO3 2-units containing non-bridging oxygens that are coordinated to the modifier cations 34 .…”