skip to main content
Language:
Primo Advanced Search
Primo Advanced Search Query Term
Primo Advanced Search prefilters
Simple Search

Direct and indirect evidence for free oxygen (O2-) in MO-silicate glasses and melts (m=Mg, Ca, Pb)

The American mineralogist, 2015-11, Vol.100 (11-12), p.2566-2578 [Peer Reviewed Journal]

GeoRef, Copyright 2020, American Geosciences Institute. ;Copyright Walter de Gruyter GmbH 2015 ;ISSN: 0003-004X ;EISSN: 1945-3027 ;DOI: 10.2138/am-2015-5336 ;CODEN: AMMIAY

Full text available

Citations Cited by
  • Title:
    Direct and indirect evidence for free oxygen (O2-) in MO-silicate glasses and melts (m=Mg, Ca, Pb)
  • Author: Nesbitt, H. Wayne ; Bancroft, G. Michael ; Henderson, Grant S ; Sawyer, Ryan ; Secco, Richard A
  • Subjects: alkaline earth metals ; Ca-silicate glass ; calcium ; CaMg-silicate glass ; experimental studies ; free oxygen in glasses ; Geochemistry ; Glass ; glass materials ; lead ; magnesium ; melts ; metals ; Mg-silicate glass ; Mineralogy ; NMR spectra ; oxygen ; Pb-silicate glass ; Phase transitions ; Raman spectra ; Silica ; silicate glasses ; silicate melts ; spectra ; X-ray photoelectron spectra ; XPS of glasses
  • Is Part Of: The American mineralogist, 2015-11, Vol.100 (11-12), p.2566-2578
  • Description: Oxygen 1s XPS spectra of a Pb-silicate glass containing 76.6 mol% PbO provide the first accurate, direct measurement of free oxide ion (O2-) in these glasses. O2- constitutes 35 (±3) mol% of total oxygen, with NBO and BO constituting, respectively, 52 (±3) and 13 (±3) mol%. All 29Si NMR and O 1s XPS results for Pb-silicate glasses indicate mol% levels of O2- containing more than ∼30 mol% PbO. The O2- abundances are consistent with equilibrium thermodynamic considerations where K∼12 for the mass action equation involving NBO, BO, and O2-. Raman and 17O NMR spectra of two CaMg-silicate glasses indicate ∼10 (±4) mol% O2- in CaMgSiO4 glass and ∼18 (±4) mol% O2- in a Ca0.36Mg0.36Si0.28O1.28 glass. Oxygen species abundances are calculated using experimental results from 13 separate 29Si NMR, 17O NMR, and Raman measurements of Mg-, Ca-, and CaMg-silicate glasses. All reveal mol% levels of O2- with ∼1 to 2.6 mol% in metasilicate glass and ∼5 to 10 mol% in orthosilicate glass. Recent Raman experimental results also indicate O2- in CaMg-silicate glasses at levels ranging from about 1 to 10 mol%. In all there are 23 separate 29Si NMR, 17O NMR, and Raman measurements indicating mol% levels of O2- in alkaline earth silicate glasses. Eight recent MD simulations of Mg, Ca, and CaMg-silicate glasses include 21 separate simulations over a wide compositional range. All indicate mol% levels of O2- in the glasses demonstrating that the MD simulations and experimental results on these systems are in accord. There are two fundamentally important implications of these studies. First, free oxygen (O2-) is an essential constituent of Pb, Mg, Ca, and CaMg binary silicate melts and glasses. It is not an "accidental" product associated with glass or melt defects. It is instead, a thermodynamically important constituent of these binary melts (and glasses). Second, where melts are equilibrated, the mass action equation relating BO, NBO, and O2- must hold across the entire Ca, Mg, CaMg, and Pb binary systems, thereby requiring the activities and mole fractions of all three species to be defined and finite in the melts. Free oxygen, however, may be too low to be detected in highly siliceous glasses using conventional spectroscopic techniques.
  • Publisher: Washington: Mineralogical Society of America
  • Language: English
  • Identifier: ISSN: 0003-004X
    EISSN: 1945-3027
    DOI: 10.2138/am-2015-5336
    CODEN: AMMIAY
  • Source: ProQuest Central
Back to results list
Go to Previous pagePrevious Result  5 NextGo to Next page
INSPIRE LIBRARY - TON DUC THANG UNIVERSITY (84-028) 37 755 057 Feedback
19 Nguyen Huu Tho St. Dist.7, HCM thuvien@tdtu.edu.vn

Copyright © 2017 INSPIRE LIBRARY - TON DUC THANG UNIVERSITY

Searching Remote Databases, Please Wait