Abstract
Ringwoodite [(Mg,Fe2+)2SiO4 spinel] has been considered as one of the most important host minerals of water in the Earth's deep mantle. Its extensive hydration was observed in high-pressure synthesis experiments and also by its natural occurrence. Water can dissolve into ringwoodite as structurally bound hydrogen cations by substituting other cations, although the hydrogen site and its occupancy remain unclear. In this study, neutron time-of-flight single-crystal Laue diffraction analysis was carried out for synthetic hydrous ringwoodite. Hydrogen cations were found only in the sites in MgO6 octahedra in the ringwoodite structure, which compensated the reduced occupancies of both magnesium and silicon cations. The refined cation occupancies suggest that the most plausible hydration mechanism is that three hydrogen cations simultaneously occupy an MgO6 octahedron, whereas four such hydrogenated octahedra surround a vacant SiO4 tetrahedron.A single-crystal neutron diffraction study was performed on hydrogen incorporation in ringwoodite, which is the most important host mineral of water in the Earth's deep mantle. Its hydrogen incorporation mechanism, bonding geometry and occupancy at the relevant hydrogen site were unambiguously revealed.
| Language | English |
|---|---|
| Pages | 115-120 |
| Number of pages | 6 |
| Journal | Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials |
| Volume | 74 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Feb 1 2018 |
| Externally published | Yes |
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Keywords
- crystallography of hydrogen
- Earth's deep mantle
- neutron diffraction
- ringwoodite
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Metals and Alloys
- Materials Chemistry
Cite this
Determination of hydrogen site and occupancy in hydrous Mg2SiO4 spinel by single-crystal neutron diffraction. / Purevjav, Narangoo; Okuchi, Takuo; Wang, Xiaoping; Hoffmann, Christina; Tomioka, Naotaka.
In: Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, Vol. 74, No. 1, 01.02.2018, p. 115-120.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Determination of hydrogen site and occupancy in hydrous Mg2SiO4 spinel by single-crystal neutron diffraction
AU - Purevjav, Narangoo
AU - Okuchi, Takuo
AU - Wang, Xiaoping
AU - Hoffmann, Christina
AU - Tomioka, Naotaka
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Ringwoodite [(Mg,Fe2+)2SiO4 spinel] has been considered as one of the most important host minerals of water in the Earth's deep mantle. Its extensive hydration was observed in high-pressure synthesis experiments and also by its natural occurrence. Water can dissolve into ringwoodite as structurally bound hydrogen cations by substituting other cations, although the hydrogen site and its occupancy remain unclear. In this study, neutron time-of-flight single-crystal Laue diffraction analysis was carried out for synthetic hydrous ringwoodite. Hydrogen cations were found only in the sites in MgO6 octahedra in the ringwoodite structure, which compensated the reduced occupancies of both magnesium and silicon cations. The refined cation occupancies suggest that the most plausible hydration mechanism is that three hydrogen cations simultaneously occupy an MgO6 octahedron, whereas four such hydrogenated octahedra surround a vacant SiO4 tetrahedron.A single-crystal neutron diffraction study was performed on hydrogen incorporation in ringwoodite, which is the most important host mineral of water in the Earth's deep mantle. Its hydrogen incorporation mechanism, bonding geometry and occupancy at the relevant hydrogen site were unambiguously revealed.
AB - Ringwoodite [(Mg,Fe2+)2SiO4 spinel] has been considered as one of the most important host minerals of water in the Earth's deep mantle. Its extensive hydration was observed in high-pressure synthesis experiments and also by its natural occurrence. Water can dissolve into ringwoodite as structurally bound hydrogen cations by substituting other cations, although the hydrogen site and its occupancy remain unclear. In this study, neutron time-of-flight single-crystal Laue diffraction analysis was carried out for synthetic hydrous ringwoodite. Hydrogen cations were found only in the sites in MgO6 octahedra in the ringwoodite structure, which compensated the reduced occupancies of both magnesium and silicon cations. The refined cation occupancies suggest that the most plausible hydration mechanism is that three hydrogen cations simultaneously occupy an MgO6 octahedron, whereas four such hydrogenated octahedra surround a vacant SiO4 tetrahedron.A single-crystal neutron diffraction study was performed on hydrogen incorporation in ringwoodite, which is the most important host mineral of water in the Earth's deep mantle. Its hydrogen incorporation mechanism, bonding geometry and occupancy at the relevant hydrogen site were unambiguously revealed.
KW - crystallography of hydrogen
KW - Earth's deep mantle
KW - neutron diffraction
KW - ringwoodite
UR - http://www.scopus.com/inward/record.url?scp=85041669023&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85041669023&partnerID=8YFLogxK
U2 - 10.1107/S2052520618000616
DO - 10.1107/S2052520618000616
M3 - Article
VL - 74
SP - 115
EP - 120
JO - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
T2 - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
JF - Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
SN - 2052-5192
IS - 1
ER -