Determination of hydrogen site and occupancy in ringwoodite by single-crystal neutron diffraction

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 24390
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Determination of hydrogen site and occupancy in ringwoodite by single-crystal neutron diffraction

Messaggio da Marco E. Ciriotti » ven 12 gen, 2018 9:14

Prossima pubblicazione.

Referenza:
▪ Purevjav, N., Okuchi, T., Wang, X., Hoffmann, C., Tomioka, N. (2018): Determination of hydrogen site and occupancy in hydrous Mg2SiO4 spinel by single-crystal neutron diffraction. Acta Crystallographica, B74, (in press).

Synopsis:
A single-crystal neutron diffraction study was performed on hydrogen 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.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 24390
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Determination of hydrogen site and occupancy in ringwoodite by single-crystal neutron diffraction

Messaggio da Marco E. Ciriotti » mer 31 gen, 2018 18:33

Pubblicazione effettuata.

Referenza:
▪ Purevjav, N., Okuchi, T., Wang, X., Hoffmann, C., Tomioka, N. (2018): Determination of hydrogen site and occupancy in hydrous Mg2SiO4 spinel by single-crystal neutron diffraction. Acta Crystallographica, B74, 115-120.

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.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Nessuno e 4 ospiti