Heavier chalcogenides display a surprisingly wide range of applications enabled by their unconventional properties. Herein, recent studies of three groups of chalcogenides from a chemical bonding perspective are reviewed to reveal the underlying reason for their wide range of applications. For IV–VI materials (GeTe, SnTe, PbTe, PbSe, and PbS), the unique property portfolio and bond‐breaking behavior are related to a novel chemical bonding mechanism termed “metavalent bonding” (MVB). The same phenomena are also found for several V₂VI₃ solids (Bi₂Te₃, Bi₂Se₃, Sb₂Te₃, and β‐As₂Te₃) and some ternary chalcogenides including crystalline (GeTe)_1–x(Sb₂Te₃)_x alloys. This provides evidence for the prevalence of MVB in these compounds. Subsequently, a quantum‐chemistry‐based map is presented. Using the transfer and sharing of electrons between adjacent atoms as its two coordinates, materials using MVB are all found in a well‐defined region of the map, characterized by sharing about one electron between adjacent atoms and only small charge transfer. This also implies that the degree of MVB is tailored either via Peierls distortions (electron sharing) or charge transfer (electron transfer), leading to the transition toward covalent bonding and ionic bonding, respectively. The tailoring of MVB provides a new approach for materials design.

中文翻译：

---

固体中的亚共价键：特征代表，它们的性质和设计选项

较重的硫族化物因其非常规特性而显示出令人惊讶的广泛应用。本文中，从化学键的角度对三族硫族化物的最新研究进行了综述，以揭示其广泛应用的根本原因。对于IV–VI材料（GeTe，SnTe，PbTe，PbSe和PbS），其独特的性能组合和键断裂行为与一种称为“元价键”（MVB）的新型化学键合机制有关。同样的现象还发现几V _2个VI ₃固体的（Bi ₂特₃，铋₂硒₃，锑₂碲₃，和β-作为₂碲₃）和一些三族硫族化物，包括晶体（GeTe）_{1– x}（Sb ₂ Te ₃）_x合金。这为这些化合物中MVB的流行提供了证据。随后，给出了基于量子化学的图。使用相邻原子之间的电子转移和共享作为其两个坐标，使用MVB的材料都位于图的明确定义的区域中，其特征是相邻原子之间共享约一个电子，并且电荷转移很小。这也意味着MVB的程度是通过Peierls畸变（电子共享）或电荷转移（电子转移）来调整的，分别导致向共价键和离子键的过渡。MVB的定制为材料设计提供了一种新方法。