On Close Parallels between the Zintl-Based Superatom Ge₉Be and Chalcogen Elements

Ever since the concept of superatoms was brought forward in the 1990s, various specific types of clusters have been proposed to mimic atomic properties and enrich the "three-dimensional periodic table". In this work, a Zintl cluster, namely, Ge₉Be, has been certified eligible to join the superatom family, owing to its surprising similarity to chalcogen elements. Having 38 valence electrons, Ge₉Be has an intrinsic desire to gain two additional electrons to achieve electronic shell closure, in which its quasi-chalcogen identity roots. Like oxygen-group elements, Ge₉Be has the potential to form stable ionic compounds with lithium, beryllium, calcium, and superalkaline-earth atom FLi₃. On the other hand, the combination of Ge₉Be and the multiple valence superatom Al₇^- results in covalent compounds resembling carbon oxides. Close parallels have also been found between (Ge₉Be)₂-based compounds and common peroxides, further evidencing the superatom characteristics of Ge₉Be. This finding puts forward an almost perfect superatom counterpart of group VIA elements and opens the door to characteristics-oriented design and synthesis of stable superatom motifs by utilizing solid Zintl clusters.