An O K-edge XANES study of glasses and crystals in the CaO-Al2O3-SiO2 (CAS) system | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  An O K-edge XANES study of glasses and crystals in the CaO-Al2O3-SiO2 (CAS) system

Type de publication:

Journal Article

Source:

Chemical Geology, Volume 259, Ticket 1-2, p.54-62 (2009)

ISBN:

0009-2541

Numéro d'accès:

WOS:000264252700008

URL:

http://www.sciencedirect.com/science/article/pii/S0009254108003823

Mots-clés:

UMR 7154 ; Physique des Minéraux et des magmas ; Minéralogie ; N° de contribution : 2419 ; XANES; Oxygen; Glasses; Structure; Calciumaluminosilicate; CAS; Calcium aluminate

Résumé:

We have measured the O K-edge XANES, spectra of a series of standard minerals and glasses in the CaO-Al2O3-SiO2 (CAS) system. Changes observed in the spectra of simple compounds like the calcium aluminates, SiO2, AlPO4, and Al2O3, where the O atoms are surrounded by network former neighbours in four-, five-, and six-fold coordination can be used to interpret structural changes occurring in CAS glasses. In particular, changes in the coordination of Ca, as well as, changes in the Al-NBO and Al-BO distribution can be resolved. For glasses along the CaO-Al2O3 join some Ca is found to be in 9-fold coordination. However, along the (xCaO:Al2O3)-SiO2 joins (where x = 1, 1.57 and 3) the average Ca coordination decreases as the proportion of CaSiO3 increases. Furthermore, along the CaSiO3-Al2O3 join the O K-edge XANES exhibits changes consistent with AlO4 Q(2) and Q(3) species being converted to Q species with the addition of Al2O3. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.