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Ohashi, Tomonori ; Sakamaki, Tatsuya ; Funakoshi, Ken-ichi ; Steinle-Neumann, Gerd ; Hattori, Takanori ; Yuan, Liang ; Suzuki, Akio:
Pressure-induced elongation of hydrogen-oxygen bond in sodium silicate melts.
In: Journal of Mineralogical and Petrological Sciences.
Bd. 120
(2025)
Heft 1
.
- 240926a.
ISSN 1349-3825
DOI: https://doi.org/10.2465/jmps.240926a
Abstract
Despite their importance in melting processes in the Earth’s interior, the structure and properties of hydrous silicate melts at high pressure remain poorly constrained due to experimental challenges. Here we explore the structures of dry and hydrated (H2O and D2O) Na6Si8O19 melt at 0-6 GPa and 1000-1300 K and glasses recovered from high pressure and temperatures by in-situ neutron and X-ray diffraction. The structures of the melts at 0-10 GPa and 3000 K are also investigated by ab-initio molecular dynamics simulation. In-situ neutron experiments reveal that the D-O distance increases with compression due to the formation of -O-D-O- bridging species, which is reproduced by the molecular dynamics simulations. The pressure-induced -O-D-O- formation reflects a more rigid incorporation of hydrogen, which acts as a mechanism for the experimentally observed higher solubility of water in silicate melts. Together with shrinking modifier domains, this process dominates the compression behavior of hydrous Na6Si8O19 melt, whereas the compression of dry Na6Si8O19 at 0-10 GPa and 3000 K is governed largely by bending of the Si-O-Si angle. The molecular dynamics simulations on hydrous Na6Si8O19 melts further suggest that the sodium ions are scavenged from its network-modifying role via 2·([4]Si-O− + Na+) → [4]Si-(O-[5]Si-O)2− + 2·Na+ and Si-O− + Na+ + Si-OH → Si-(O-H-O-Si)− + Na+ with increasing pressure.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Forschungseinrichtungen > Zentrale wissenschaftliche Einrichtungen > Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik - BGI |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie |
| Eingestellt am: | 02 Jun 2026 06:06 |
| Letzte Änderung: | 02 Jun 2026 06:06 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/97795 |