Structural studies in lead germanate glasses: EXAFS and vibrational spectroscopy
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Data
1993-12-01
Autores
Ribeiro, S.J.L [UNESP]
Dexpert-Ghys, J
Piriou, B
Mastelaro, V.R
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Resumo
The Raman, IR absorption and EXAFS spectra at the Ge K-edge and Pb LIII-edge of eight lead germanate glasses, with general formula xPbO(1-x)GeO2 with x = 0.20, 0.25, 0.33, 0.40, 0.50, 0.53, 0.56 and 0.60, have been measured. The occurrence of [GeO6] units besides [GeO4] could not be deduced unambiguously from the data. The vibrational and EXAFS data agree with a progressive depolymerization of the network. Starting from all Ge atoms linked to four bridging oxygens in GeO2 (x = 0), the number of tetrahedral units with one or two non-bridging oxygens increases with x. At low content, Pb2+ ions act as modifiers in the germanate structure, but to a lesser extent than an equivalent number of alkaline ions. © 1993.
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Palavras-chave
Atoms, Ions, Light absorption, Molecular structure, Oxygen, Alkaline ions, Bridging oxygen, Depolymerization, Lead germanate glasses, Nonbridging oxygens, Glass
Como citar
Journal of Non-Crystalline Solids, v. 159, n. 3, p. 213-221, 1993.