Magnesium oxide-water compounds at megabar pressure and implications on planetary interiors

Shuning Pan, Tianheng Huang, Allona Vazan, Zhixin Liang, Cong Liu, Junjie Wang, Chris J. Pickard, Hui-Tian Wang, Dingyu Xing and Jian Sun ()
Additional contact information
Shuning Pan: Nanjing University
Tianheng Huang: Nanjing University
Allona Vazan: Astrophysics Research Center of the Open University (ARCO), The Open University of Israel
Zhixin Liang: Nanjing University
Cong Liu: Nanjing University
Junjie Wang: Nanjing University
Chris J. Pickard: Theory of Condensed Matter Group, Cavendish Laboratory, J. J. Thomson Avenue
Hui-Tian Wang: Nanjing University
Dingyu Xing: Nanjing University
Jian Sun: Nanjing University

Nature Communications, 2023, vol. 14, issue 1, 1-9

Abstract: Abstract Magnesium Oxide (MgO) and water (H2O) are abundant in the interior of planets. Their properties, and in particular their interaction, significantly affect the planet interior structure and thermal evolution. Here, using crystal structure predictions and ab initio molecular dynamics simulations, we find that MgO and H2O can react again at ultrahigh pressure, although Mg(OH)2 decomposes at low pressure. The reemergent MgO-H2O compounds are: Mg2O3H2 above 400 GPa, MgO3H4 above 600 GPa, and MgO4H6 in the pressure range of 270–600 GPa. Importantly, MgO4H6 contains 57.3 wt % of water, which is a much higher water content than any reported hydrous mineral. Our results suggest that a substantial amount of water can be stored in MgO rock in the deep interiors of Earth to Neptune mass planets. Based on molecular dynamics simulations we show that these three compounds exhibit superionic behavior at the pressure-temperature conditions as in the interiors of Uranus and Neptune. Moreover, the water-rich compound MgO4H6 could be stable inside the early Earth and therefore may serve as a possible early Earth water reservoir. Our findings, in the poorly explored megabar pressure regime, provide constraints for interior and evolution models of wet planets in our solar system and beyond.

Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41467-023-36802-8 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:14:y:2023:i:1:d:10.1038_s41467-023-36802-8

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-023-36802-8

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().