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Incorporation of Mg2+ in surface Ca2+ sites of aragonite: an ab initio study
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| Title: | Incorporation of Mg2+ in surface Ca2+ sites of aragonite: an ab initio study |
| Authors: | Kawano, Jun Browse this author | | Sakuma, Hiroshi Browse this author | | Nagai, Takaya Browse this author |
| Keywords: | Aragonite | | Impurity | | Surface structure | | First-principles calculation |
| Issue Date: | Dec-2015 |
| Publisher: | Springer |
| Journal Title: | Progress in earth and planetary science |
| Volume: | 2 |
| Start Page: | UNSP 7 |
| Publisher DOI: | 10.1186/s40645-015-0039-4 |
| Abstract: | First-principles calculations of Mg2+-containing aragonite surfaces are important because Mg2+ can affect the growth of calcium carbonate polymorphs. New calculations that incorporate Mg2+ substitution for Ca2+ in the aragonite {001} and {110} surfaces clarify the stability of Mg2+ near the aragonite surface and the structure of the Mg2+-containing aragonite surface. The results suggest that the Mg2+ substitution energy for Ca2+ at surface sites is lower than that in the bulk structure and that Mg2+ can be easily incorporated into the surface sites; however, when Mg2+ is substituted for Ca2+ in sites deeper than the second Ca2+ layer, the substitution energy approaches the value of the bulk structure. Furthermore, Mg2+ at the aragonite surface has a significant effect on the surface structure. In particular, CO3 groups rotate to achieve six-coordinate geometry when Mg2+ is substituted for Ca2+ in the top layer of the {001} surface or even in the deeper layers of the {110} surface. The rotation may relax the atomic structure around Mg2+ and reduces the substitution energy. The structural rearrangements observed in this study of the aragonite surface induced by Mg2+ likely change the stability of aragonite and affect the polymorph selection of CaCO3. |
| Rights: | http://creativecommons.org/licenses/by/4.0 |
| Type: | article |
| URI: | http://hdl.handle.net/2115/60343 |
| Appears in Collections: | 創成研究機構 (Creative Research Institution) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 川野 潤
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