Lee T H, Elliott S R
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
School of Materials Science and Engineering, Kyungpook National University, Daegu, South Korea.
Nat Commun. 2022 Mar 18;13(1):1458. doi: 10.1038/s41467-022-29054-5.
The concept of hypervalency emerged as a notion for chemical bonding in molecules to explain the atomic coordination in hypervalent molecules that violates the electron-octet rule. Despite its significance, however, hypervalency in condensed phases, such as amorphous solids, remains largely unexplored. Using ab initio molecular-dynamics simulations, we report here the underlying principles of hypervalency in amorphous chalcogenide materials, in terms of the behaviour of hypervalent structural units, and its implicit relationship with material properties. The origin of a material-dependent tendency towards hypervalency is made evident with the multi-centre hyperbonding model, from which its relationship to abnormally large Born effective charges is also unambiguously revealed. The hyperbonding model is here extended to include interactions with cation s lone pairs (LPs); such deep-lying LPs can also play a significant role in determining the properties of these chalcogenide materials. The role of hypervalency constitutes an indispensable and important part of chemical interactions in amorphous and crystalline chalcogenide solids.
超价的概念最初是作为一种用于解释分子中化学键合的概念，以说明超价分子中违反电子八隅体规则的原子配位情况。然而，尽管其具有重要意义，但在凝聚相中，如非晶态固体中的超价现象在很大程度上仍未得到探索。通过从头算分子动力学模拟，我们在此报告非晶态硫族化物材料中超价现象的基本原理，具体涉及超价结构单元的行为，及其与材料性质的隐含关系。多中心超键合模型揭示了材料依赖的超价倾向的起源，同时也明确揭示了其与异常大的玻恩有效电荷的关系。在此，超键合模型得到扩展，以纳入与阳离子孤对（LPs）的相互作用；这种深层的孤对在决定这些硫族化物材料的性质方面也可发挥重要作用。超价现象的作用构成非晶态和晶态硫族化物固体中化学相互作用不可或缺的重要部分。
