Structures and stabilities of alkaline earth metal peroxides XO2 (X = Ca, Be, Mg) studied by a genetic algorithm

TitleStructures and stabilities of alkaline earth metal peroxides XO2 (X = Ca, Be, Mg) studied by a genetic algorithm
Publication TypeJournal Article
Year of Publication2013
AuthorsZhao X, Nguyen MC, Wang CZ, Ho KM
Journal TitleRSC Advances
Volume3
Pages22135-22139
Date Published11/28
Type of ArticleArticle
ISBN Number2046-2069
Accession NumberWOS:000326056600140
Keywordsab-initio data, augmented-wave method, basis-set, effective potentials, total-energy calculations
Abstract

The structures and stabilities of alkaline earth metal peroxides XO2 (X = Ca, Be, Mg) were studied using an adaptive genetic algorithm (GA) for global structure optimization in combination with first-principles calculations. From the adaptive GA search, we obtained an orthorhombic structure for CaO2 with 12 atoms in the unit cell, which is energetically more favorable than the previously proposed structures. Reaction energy of the decomposition CaO2 -> CaO + 1/2O(2) determined by density functional theory (DFT) calculation shows that this orthorhombic calcium peroxide structure is thermodynamically stable. The simulated X-ray diffraction (XRD) pattern using our predicted structure is in excellent agreement with experimental data. We also show that crystal phase BeO2 is unlikely to exist under normal conditions. MgO2 has a cubic pyrite structure, but it is not stable against decomposition: MgO2 -> MgO + 1/2O(2).

URL<Go to ISI>://WOS:000326056600140
DOI10.1039/c3ra43617a