Unconventional Stoichiometries of Na–O Compounds at High Pressures
It has been realized that the stoichiometries of compounds may change under high pressure, which is crucial in the discovery of novel materials. This work uses systematic structure exploration and first-principles calculations to consider the stability of different stoichiometries of Na–O compounds...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-12-01
|
| Series: | Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1944/14/24/7650 |
| _version_ | 1797502708104560640 |
|---|---|
| author | Lihua Yang Yukai Zhang Yanli Chen Xin Zhong Dandan Wang Jihui Lang Xin Qu Jinghai Yang |
| author_facet | Lihua Yang Yukai Zhang Yanli Chen Xin Zhong Dandan Wang Jihui Lang Xin Qu Jinghai Yang |
| author_sort | Lihua Yang |
| collection | DOAJ |
| description | It has been realized that the stoichiometries of compounds may change under high pressure, which is crucial in the discovery of novel materials. This work uses systematic structure exploration and first-principles calculations to consider the stability of different stoichiometries of Na–O compounds with respect to pressure and, thus, construct a high-pressure stability field and convex hull diagram. Four previously unknown stoichiometries (NaO<sub>5</sub>, NaO<sub>4</sub>, Na<sub>4</sub>O, and Na<sub>3</sub>O) are predicted to be thermodynamically stable. Four new phases (<i>P</i>2<i>/m</i> and <i>Cmc</i>2<sub>1</sub> NaO<sub>2</sub> and <i>Immm</i> and <i>C</i>2<i>/m</i> NaO<sub>3</sub>) of known stoichiometries are also found. The O-rich stoichiometries show the remarkable features of all the O atoms existing as quasimolecular O<sub>2</sub> units and being metallic. Calculations of the O–O bond lengths and Bader charges are used to explore the electronic properties and chemical bonding of the O-rich compounds. The Na-rich compounds stabilized at extreme pressures (P > 200 GPa) are electrides with strong interstitial electron localization. The <i>C</i>2<i>/c</i> phase of Na<sub>3</sub>O is found to be a zero-dimensional electride with an insulating character. The <i>Cmca</i> phase of Na<sub>4</sub>O is a one-dimensional metallic electride. These findings of new compounds with unusual chemistry might stimulate future experimental and theoretical investigations. |
| first_indexed | 2024-03-10T03:39:56Z |
| format | Article |
| id | doaj.art-4b505e6e35be49e1b7b296279b00cd13 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T03:39:56Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-4b505e6e35be49e1b7b296279b00cd132023-11-23T09:21:00ZengMDPI AGMaterials1996-19442021-12-011424765010.3390/ma14247650Unconventional Stoichiometries of Na–O Compounds at High PressuresLihua Yang0Yukai Zhang1Yanli Chen2Xin Zhong3Dandan Wang4Jihui Lang5Xin Qu6Jinghai Yang7Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaKey Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, National Demonstration Center for Experimental Physics Education, College of Physics, Jilin Normal University, Siping 136000, ChinaIt has been realized that the stoichiometries of compounds may change under high pressure, which is crucial in the discovery of novel materials. This work uses systematic structure exploration and first-principles calculations to consider the stability of different stoichiometries of Na–O compounds with respect to pressure and, thus, construct a high-pressure stability field and convex hull diagram. Four previously unknown stoichiometries (NaO<sub>5</sub>, NaO<sub>4</sub>, Na<sub>4</sub>O, and Na<sub>3</sub>O) are predicted to be thermodynamically stable. Four new phases (<i>P</i>2<i>/m</i> and <i>Cmc</i>2<sub>1</sub> NaO<sub>2</sub> and <i>Immm</i> and <i>C</i>2<i>/m</i> NaO<sub>3</sub>) of known stoichiometries are also found. The O-rich stoichiometries show the remarkable features of all the O atoms existing as quasimolecular O<sub>2</sub> units and being metallic. Calculations of the O–O bond lengths and Bader charges are used to explore the electronic properties and chemical bonding of the O-rich compounds. The Na-rich compounds stabilized at extreme pressures (P > 200 GPa) are electrides with strong interstitial electron localization. The <i>C</i>2<i>/c</i> phase of Na<sub>3</sub>O is found to be a zero-dimensional electride with an insulating character. The <i>Cmca</i> phase of Na<sub>4</sub>O is a one-dimensional metallic electride. These findings of new compounds with unusual chemistry might stimulate future experimental and theoretical investigations.https://www.mdpi.com/1996-1944/14/24/7650high pressurestructure predictionelectride |
| spellingShingle | Lihua Yang Yukai Zhang Yanli Chen Xin Zhong Dandan Wang Jihui Lang Xin Qu Jinghai Yang Unconventional Stoichiometries of Na–O Compounds at High Pressures Materials high pressure structure prediction electride |
| title | Unconventional Stoichiometries of Na–O Compounds at High Pressures |
| title_full | Unconventional Stoichiometries of Na–O Compounds at High Pressures |
| title_fullStr | Unconventional Stoichiometries of Na–O Compounds at High Pressures |
| title_full_unstemmed | Unconventional Stoichiometries of Na–O Compounds at High Pressures |
| title_short | Unconventional Stoichiometries of Na–O Compounds at High Pressures |
| title_sort | unconventional stoichiometries of na o compounds at high pressures |
| topic | high pressure structure prediction electride |
| url | https://www.mdpi.com/1996-1944/14/24/7650 |
| work_keys_str_mv | AT lihuayang unconventionalstoichiometriesofnaocompoundsathighpressures AT yukaizhang unconventionalstoichiometriesofnaocompoundsathighpressures AT yanlichen unconventionalstoichiometriesofnaocompoundsathighpressures AT xinzhong unconventionalstoichiometriesofnaocompoundsathighpressures AT dandanwang unconventionalstoichiometriesofnaocompoundsathighpressures AT jihuilang unconventionalstoichiometriesofnaocompoundsathighpressures AT xinqu unconventionalstoichiometriesofnaocompoundsathighpressures AT jinghaiyang unconventionalstoichiometriesofnaocompoundsathighpressures |