Investigation of hydrogen sites of wadsleyite: A neutron diffraction study

Asami Sano-Furukawa, Takahiro Kuribayashi, Kazuki Komatsu, Takehiko Yagi, Eiji Otani

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

A neutron powder diffraction experiment was conducted to refine the hydrogen position of Mg-endmember deuterated wadsleyite. Preliminary refinement using the dry-structure determined by single crystal X-ray diffraction reveals a maximum peak Q1 of nuclear density in the difference Fourier map at the M3 octahedral edge, between the O1 and O4 atoms (3.071(3). å). Full Rietveld refinement was conducted assuming that the maximum peak corresponds to deuterium atom. The deuterium position was determined as (0.096, 0.289, 0.315) with occupancy of 8.2%. The O1-D1 vector lies along M3 octahedral edge pointing O4 atom, and the bond length is determined as 1.037(15). å for O1-D1, and 2.041(15). å for D1cṫO4. The O1-D1cṫO4 geometry is almost linear with angle of 171.7(5) ° The residual peak Q2 was found in the map at (0, 0.172, 0.268), suggesting the existence of a bent hydrogen bond between O1cṫO3 (3.035. å) of the M3 octahedral edge. The respective distances from the surrounding oxygen atoms are 0.97 and 2.13. å for O1-Q2 and Q2cṫO3. The O1-Q2cṫO3 configuration is nonlinear, with angle of 154.4 ° These results reveal that the dominant site of protonation in wadsleyite is the O1 site, which is consistent with the previous prediction.

Original languageEnglish
Pages (from-to)56-62
Number of pages7
JournalPhysics of the Earth and Planetary Interiors
Volume189
Issue number1-2
DOIs
Publication statusPublished - 2011 Nov 1

Keywords

  • Mantle transition zone
  • Neutron diffraction
  • Wadsleyite
  • Water

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science
  • Physics and Astronomy (miscellaneous)
  • Astronomy and Astrophysics

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