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| Auteurs principaux: | , , , , , , , , |
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| Format: | Preprint |
| Publié: |
2025
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| Accès en ligne: | https://arxiv.org/abs/2510.20395 |
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| _version_ | 1866915571616972800 |
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| author | Lv, Yang Li, Junwei Li, Jianfu Liu, Yong Yuan, Jianan Lin, 1 Jiani Kawaguchi-Imada, Saori Hu, Qingyang Wang, Xiaoli |
| author_facet | Lv, Yang Li, Junwei Li, Jianfu Liu, Yong Yuan, Jianan Lin, 1 Jiani Kawaguchi-Imada, Saori Hu, Qingyang Wang, Xiaoli |
| contents | An isolated calcium (Ca) atom has empty d-orbitals under ambient conditions. However, s-d band hybridization has been observed in both elemental Ca and compounds by manipulating thermodynamic conditions. Here, we reveal that the Ca 3d-band can even capture electrons from halogen atoms under pressure, exhibiting anionic behaviors in iodides. We predict a CsCl-type monovalent CaI at above 50 GPa by employing first-principles structural searching and successfully identified the phase at 84 GPa using in situ X-ray diffraction. We further reveal that, due to the effect of orbital broadening, unusual charge transfer from the 5p orbitals of I to the 3d orbitals of Ca in CaI, gradually reverses the ionicity of Ca and becomes the anionic ICa at 485 GPa. Multivalent Ca stabilizes a set of metallic iodides with eight- to ten-fold iodine hyper-coordination. Our findings demonstrate that the valence states of Ca can vary from negative to +2, suggesting much greater complexity of Ca chemistry under ultrahigh pressures. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_20395 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Unlock Anionic Behavior of Calcium Through Pressure Engineering Lv, Yang Li, Junwei Li, Jianfu Liu, Yong Yuan, Jianan Lin, 1 Jiani Kawaguchi-Imada, Saori Hu, Qingyang Wang, Xiaoli Materials Science An isolated calcium (Ca) atom has empty d-orbitals under ambient conditions. However, s-d band hybridization has been observed in both elemental Ca and compounds by manipulating thermodynamic conditions. Here, we reveal that the Ca 3d-band can even capture electrons from halogen atoms under pressure, exhibiting anionic behaviors in iodides. We predict a CsCl-type monovalent CaI at above 50 GPa by employing first-principles structural searching and successfully identified the phase at 84 GPa using in situ X-ray diffraction. We further reveal that, due to the effect of orbital broadening, unusual charge transfer from the 5p orbitals of I to the 3d orbitals of Ca in CaI, gradually reverses the ionicity of Ca and becomes the anionic ICa at 485 GPa. Multivalent Ca stabilizes a set of metallic iodides with eight- to ten-fold iodine hyper-coordination. Our findings demonstrate that the valence states of Ca can vary from negative to +2, suggesting much greater complexity of Ca chemistry under ultrahigh pressures. |
| title | Unlock Anionic Behavior of Calcium Through Pressure Engineering |
| topic | Materials Science |
| url | https://arxiv.org/abs/2510.20395 |