Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 1 September 1989:
Vol. 245. no. 4921, pp. 962 - 964
DOI: 10.1126/science.245.4921.962
Prev | Table of Contents | Next

Articles

Silicon Coordination and Speciation Changes in a Silicate Liquid at High Pressures

XIANYU XUE 1, MASAMI KANZAKI 1, REIDAR G. TRØNNES 1, and JONATHAN F. STEBBINS 2

1 C. M. Scarfe Laboratory of Experimental Petrology, Department of Geology and Institute of Earth and Planetary Physics, University of Alberta, Edmonton, Canada T6G 2E3.
2 Department of Geology, Stanford University, Stanford, CA 94305.

Coordination and local geometry around Si cations in silicate liquids are of primary importance in controlling the chemical and physical properties of magmas. Pressure-induced changes from fourfold to sixfold coordination of Si in silicate glass samples quenched from liquids has been detected with 29Si magic-angle spinning nuclear magnetic resonance spectrometry. Samples of Na2Si2O5 glass quenched from 8 gigapascals and 1500°C contained about 1.5 percent octahedral Si, which was demonstrably part of a homogeneous, amorphous phase. The dominant tetrahedral Si speciation in these glasses became disproportionated to a more random distribution of bridging and nonbridging oxygens with increasing pressure.

Submitted on May 5, 1989
Accepted on July 7, 1989


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Simultaneous aluminum, silicon, and sodium coordination changes in 6 GPa sodium aluminosilicate glasses.
K. E. Kelsey, J. F. Stebbins, J. L. Mosenfelder, and P. D. Asimow (2009)
American Mineralogist 94, 1205-1215
   Abstract »    Full Text »    PDF »
X-ray Raman scattering study of MgSiO3 glass at high pressure: Implication for triclustered MgSiO3 melt in Earth's mantle.
S. K. Lee, J.-F. Lin, Y. Q. Cai, N. Hiraoka, P. J. Eng, T. Okuchi, H.-k. Mao, Y. Meng, M. Y. Hu, P. Chow, et al. (2008)
PNAS 105, 7925-7929
   Abstract »    Full Text »    PDF »
Effect of structural transitions on properties of high-pressure silicate melts: 27Al NMR, glass densities, and melt viscosities.
J. R. Allwardt, J. F. Stebbins, H. Terasaki, L.-S. Du, D. J. Frost, A. C. Withers, M. M. Hirschmann, A. Suzuki, and E. Ohtani (2007)
American Mineralogist 92, 1093-1104
   Abstract »    Full Text »    PDF »
Cation order and hydrogen bonding of high-pressure phases in the Al2O3-SiO2-H2O system: An NMR and Raman study.
X. Xue, M. Kanzaki, H. Fukui, E. Ito, and T. Hashimoto (2006)
American Mineralogist 91, 850-861
   Abstract »    Full Text »    PDF »
Al Coordination Changes in High-Pressure Aluminosilicate Liquids.
J. L. Yarger, K. H. Smith, R. A. Nieman, J. Diefenbacher, G. H. Wolf, B. T. Poe, and P. F. McMillan (1995)
Science 270, 1964-1967
   Abstract »    PDF »
Magnesium and Calcium Aluminate Liquids: In Situ High-Temperature 27Al NMR Spectroscopy.
B. T. Poe, P. F. McMillan, B. Cote, D. Massiot, and J. P. Coutures (1993)
Science 259, 786-788
   Abstract »    PDF »
Pressure-Induced Coordination Changes in Alkali-Germanate Melts: An in Situ Spectroscopic Investigation.
D. L. Farber, D. L. Farber, and Q. Williams (1992)
Science 256, 1427-1430
   Abstract »    PDF »
A Novel Topological Compression Mechanism in a Covalent Liquid.
Lars. Stixrude, L. Stixrude, and M. S. T. Bukowinski (1990)
Science 250, 541-543
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)