Novel stable compounds in the Mg-O system under high pressure

Qiang Zhu, Artem R. Oganov, Andriy O. Lyakhov

Research output: Contribution to journalArticlepeer-review

87 Citations (Scopus)

Abstract

Using ab initio evolutionary simulations, we explore the entire range of possible stoichiometries for the Mg-O system at pressures of up to 850 GPa. In addition to MgO, our calculations find that two extraordinary compounds MgO 2 and Mg3O2 become thermodynamically stable at 116 GPa and 500 GPa, respectively. Detailed chemical bonding analysis shows large charge transfer in all magnesium oxides. MgO2 contains peroxide ions [O-O]2-, while non-nuclear electron density maxima play the role of anions in the electride compound Mg3O2. The latter compound is calculated to have a much narrower band gap compared to MgO and MgO2. We discuss the conditions under which MgO2 and Mg3O2 could exist in planetary interiors.

Original languageEnglish
Pages (from-to)7696-7700
Number of pages5
JournalPhysical Chemistry Chemical Physics
Volume15
Issue number20
DOIs
Publication statusPublished - 28 May 2013
Externally publishedYes

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