1. 2. © Local Structure And Redox State Of Vanadium In Strontium- Vanadate Glasses Khattak, GD; Tabet, N ELSEVIER SCIENCE BV, JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA; pp: ; Vol: 136 King Fahd University of Petroleum & Minerals Summary The local structure of vanadate glasses containing SrO with the nominal composition [(SrO)(x)(V2O5)(1-x)], where 0.2 less than or equal to x less than or equal to 0.5, have been investigated by X-ray photoelectron spectroscopy (XPS). The core-level binding energies of V 2p, Sr 3p and 0 Is have been measured. The doublet peaks attributed to Sr 3p(3/2) and Sr 3p(1/2) in the Sr 3p spectra have essentially the same binding energies for all glass samples, regardless of the composition The 0 Is core level spectra, however, show slight asymmetry for the glass samples with x = 0.2 and 0.3 which results from two contributions, one from the presence of oxygen atoms in the V-O-V environment called bridging oxygen (BO) and the other from oxygen atoms in an Sr-O-V and V = 0 environment called non-bridging oxygen (NBO). For samples with x = 0.4 and 0.5 the 0 Is spectra were symmetric indicating the existence of only one type of oxygen configuration (NBO). There is a good agreement between the measured (XPS) and calculated values for MUM The quantitative ratio, [V4+/Vtotal I, for each glass sample, has been determined from the analysis of the V 2p core level spectra. The ratio remains practically constant independent of vanadium concentration within experimental uncertainties. (C) 2004 Elsevier B.V. All rights reserved. References: AUSTIN IG, 1969, ADV PHYS, V18, P41 BACHMANN HG, 1961, Z KRISTALLOGR, V115, P110 Copyright: King Fahd University of Petroleum & Minerals;

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