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Liang HP, Li CN, Zhou R, Xu X, Zhang X, Yang J, Wei SH. Critical Role of Configurational Disorder in Stabilizing Chemically Unfavorable Coordination in Complex Compounds. J Am Chem Soc 2024; 146:16222-16228. [PMID: 38778012 DOI: 10.1021/jacs.4c04201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The crystal structure of a material is essentially determined by the nature of its chemical bonding. Consequently, the atomic coordination intimately correlates with the degree of ionicity or covalency of the material. Based on this principle, materials with similar chemical compositions can be successfully categorized into different coordination groups. However, counterexamples have recently emerged in complex ternary compounds. For instance, covalent IB-IIIA-VIA2 compounds, such as AgInS2, prefer a tetrahedrally coordinated structure (TCS), while ionic IA-VA-VIA2 compounds, such as NaBiS2, would favor an octahedrally coordinated structure (OCS). One naturally expects that IB-VA-VIA2 compounds with intermediate ionicity or covalency, such as AgBiS2, should then have a mix-coordinated structure (MCS) consisting of covalent AgS4 tetrahedra and ionic BiS6 octahedra. Surprisingly, only the experimental presence of the OCS was observed for AgBiS2. To resolve this puzzle, we perform first-principles studies of the phase stabilities of ternary compounds at finite temperatures. We find that AgBiS2 indeed prefers MCS at the ground state, in agreement with the typical expectation, but under experimental synthesis conditions, disordered OCS becomes energetically more favorable because of its low mixing energy and high configurational entropy. Our work elucidates the critical role of configurational disorder in stabilizing chemically unfavorable coordination, providing a rigorous rationale for the anomalous coordination preference in IB-VA-VIA2 compounds.
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Affiliation(s)
- Han-Pu Liang
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Chuan-Nan Li
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ran Zhou
- Department of Physics, Beihang University, Beijing 100191, China
| | - Xun Xu
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Xie Zhang
- School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jingxiu Yang
- Key Laboratory for Comprehensive Energy Saving of Cold Regions Architecture of Ministry of Education, School of Materials Science and Engineering, Jilin Jianzhu University, Changchun 130118, China
| | - Su-Huai Wei
- Beijing Computational Science Research Center, Beijing 100193, China
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Bernges T, Peilstöcker J, Dutta M, Ohno S, Culver SP, Biswas K, Zeier WG. Local Structure and Influence of Sb Substitution on the Structure-Transport Properties in AgBiSe 2. Inorg Chem 2019; 58:9236-9245. [PMID: 31247817 DOI: 10.1021/acs.inorgchem.9b00874] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Owing to their intrinsically low thermal conductivity and chemical diversity, materials within the I-V-VI2 family, and especially AgBiSe2, have recently attracted interest as promising thermoelectric materials. However, further investigations are needed in order to develop a more fundamental understanding of the origin of the low thermal conductivity in AgBiSe2, to evaluate possible stereochemical activity of the 6s2 lone pair of Bi3+, and to further elaborate on chemical design approaches for influencing the occurring phase transitions. In this work, a combination of temperature-dependent X-ray diffraction, Rietveld refinements of laboratory X-ray diffraction data, and pair distribution function analyses of synchrotron X-ray diffraction data is used to tackle the influence of Sb substitution within AgBi1-xSbxSe2 (0 ⩽ x ⩽ 0.15) on the phase transitions, local distortions, and off-centering of the structure. This work shows that, similar to other lone-pair-containing materials, local off-centering and distortions can be found in AgBiSe2. Furthermore, electronic and thermal transport measurements, in combination with the modeling of point-defect scattering, highlight the importance of structural characterizations toward understanding changes induced by elemental substitutions. This work provides new insights into the structure-transport correlations of the thermoelectric AgBiSe2.
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Affiliation(s)
- Tim Bernges
- Institute of Physical Chemistry , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
| | - Jan Peilstöcker
- Institute of Physical Chemistry , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
| | - Moinak Dutta
- New Chemistry Unit , Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) , Jakkur P.O., Bangalore 560064 , India
| | - Saneyuki Ohno
- Institute of Physical Chemistry , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
| | - Sean P Culver
- Institute of Physical Chemistry , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
| | - Kanishka Biswas
- New Chemistry Unit , Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) , Jakkur P.O., Bangalore 560064 , India
| | - Wolfgang G Zeier
- Institute of Physical Chemistry , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig-University Giessen , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
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