Physics and Chemistry of Minerals

, Volume 21, Issue 8, pp 510–515

Pressure-induced coordination change of Ti in silicate glass: a XANES study

  • E. Paris
  • D. B. Dingwell
  • F. A. Seifert
  • A. Mottana
  • C. Romano
Article

DOI: 10.1007/BF00203925

Cite this article as:
Paris, E., Dingwell, D.B., Seifert, F.A. et al. Phys Chem Minerals (1994) 21: 510. doi:10.1007/BF00203925

Abstract

The effect of pressure on titanium coordination in glasses, with composition K2TiSi4O11, quenched isobarically from liquids equilibrated at high pressure (5, 10, 15, 20, 25, 30 kbar respectively) and T=1600° C has been investigated by X-ray absorption spectroscopy (XAS). The XANES spectra collected at the Ti K-edge clearly show a variation with pressure that is related to changes in the geometrical environment around the Ti atoms. By comparison with spectra of standard materials, the XANES spectra of the glasses suggest a relatively low average coordination number (near 5) in samples quenched at low pressure and a higher coordination number (near 6) in samples quenched from the highest pressure. The combination of XANES data with density and compressibility measurements supports the idea that a mixture of 6- and lower coordinated (4- and/ or 5-coordinated) Ti geometries are present in the 1 bar glass, and an increasing proportion of 6-coordinated Ti occurs in the glasses synthesized at progressively higher pressures.

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • E. Paris
    • 1
  • D. B. Dingwell
    • 2
  • F. A. Seifert
    • 2
  • A. Mottana
    • 3
  • C. Romano
    • 2
  1. 1.Dipartimento di Scienze della TerraUniversita' di CamerinoCamerinoItaly
  2. 2.Bayerisches Geoinstitut, Universität BayreuthBayreuthGermany
  3. 3.Dipartimento di Scienze GeologicheTerza Universita' di RomaRomaItaly