SP3-Hybridization Feature of Ag4 Superatom in Superatomic Molecules

Abstract

Analogous to atoms, superatoms can be used as building blocks to compose molecules and materials. To demonstrate this idea, the possibility of using tetrahedral Ag4 cluster to form a series of superatomic molecules Ag4X4 (X=H, Li, Na, K, Cu, Ag, Au and F, Cl, Br) is discussed. Based on the super valence bond model, a tetrahedral Ag4 cluster can be viewed as a 4-electron superatom, which can mimic a sp3 hybridization C atom. By comparison of the representative superatomic molecules Ag4X4 (X=Au, Cl) with the corresponding simple molecules CX4 (X=H, Cl), the similarities in terms of chemical bonding patterns and molecular orbitals (MOs) are conspicuous. Energy calculations predict that the Ag4 superatom can bind with all the involved ligands. Furthermore, the stabilities of superatomic molecules are enhanced by the large gaps of the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO gaps) and high aromaticity. Our studies may find applications in assembling materials with superatoms.