Artigo
Structural study of tungstate fluorophosphate glasses by Raman and X-ray absorption spectroscopy
Fecha
2005-05-01Registro en:
Journal of Solid State Chemistry. San Diego: Academic Press Inc. Elsevier B.V., v. 178, n. 5, p. 1533-1538, 2005.
0022-4596
10.1016/j.jssc.2004.10.032
WOS:000228934800025
2998503841917815
6446047463034654
Autor
Universidade Estadual Paulista (Unesp)
Univ Rennes 1
Resumen
Transparent glasses were synthesized in the NaPO3-BaF2 WO3 tertiary system and several structural characterizations were performed by X-ray absorption spectroscopy (XANES) at the tungsten L-I and L-III absorption edges and by Raman spectroscopy. Special attention was paid to the coordination state of tungsten atoms in the vitreous network.XANES investigations showed that tungsten atoms are only six-fold coordinated (octahedra WO6) and that these glasses are free of tungstate tetrahedra (WO4).In addition, Raman spectroscopy allowed to identify a break in the linear phosphate chains as the amount of WO3 increases and the formation of P-O-W bonds in the vitreous network indicating the modifier behavior of WO6 octahedra in the glass network. Based on XANES data, we suggested a new attribution of several Raman absorption bands which allowed to identify the presence of W-O- and W=O terminal bonds and a progressive apparition of W-O-W bridging bonds for the most WO3 concentrated samples (≥ 30% molar) due to the formation of WO6 clusters. © 2004 Elsevier B.V. All rights reserved.