|
|
|
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Institute for Study of the Earths Interior, Okayama University, Misasa, Tottori, 682-0193 Japan
2 Faculty of Science, Kumamoto University, Kurokami 2-36-1, Kumamoto 860-8555 Japan
Correspondence: * E-mail: xianyu{at}misasa.okayama-u.ac.jp
Topaz-OH, phase egg, and
-AlOOH are hydrous phases in the Al2O3-SiO2-H2O system that have been found to be stable at successively higher pressures up to those corresponding to the lower mantle, and thus they may be important water reservoirs in the deep mantle. We have applied 1H, 29Si, and 27Al nuclear magnetic resonance (NMR) and Raman spectroscopy to shed new light on the structure of these phases. 29Si and 27Al NMR results clearly revealed that the Si-Al distribution in phase egg is partially disordered. The presence of structural disorder in topaz-OH was also confirmed. 1H NMR and Raman data are both consistent with strong, but asymmetric hydrogen bonding in
-AlOOH and phase egg, and a range of hydrogen bonding distances in topaz-OH. The observed structural disorder and hydrogen bonding could be responsible for the high upper temperature stability limits (1500~1700 °C) of phase egg and topaz-OH, and are also relevant to the incorporation mechanisms of water in nominally anhydrous stishovite.
Key Words: NMR spectroscopy topaz phase egg
-AlOOH Raman spectroscopy crystal structure order-disorder
This article has been cited by other articles:
![]() |
X. Xue, M. Kanzaki, and A. Shatskiy Dense hydrous magnesium silicates, phase D, and superhydrous B: New structural constraints from one- and two-dimensional 29Si and 1H NMR American Mineralogist, July 1, 2008; 93(7): 1099 - 1111. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Tsuchiya, T. Tsuchiya, and R. M. Wentzcovitch Vibrational properties of {delta}-AlOOH under pressure American Mineralogist, February 1, 2008; 93(2-3): 477 - 482. [Abstract] [Full Text] [PDF] |
||||
![]() |
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 Effect of structural transitions on properties of high-pressure silicate melts: 27Al NMR, glass densities, and melt viscosities American Mineralogist, July 1, 2007; 92(7): 1093 - 1104. [Abstract] [Full Text] [PDF] |
||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |