The superatomic molecule theory of metal clusters

Using special metal clusters (superatoms) as superatomic building blocks for hierarchically assembled materials allows these properties to be incorporated into designer materials with tailored properties. But how to assemble the superatoms to form materials is a critical problem, and no clear understanding until now. The assembly of the superatoms is basically equivalent to superatoms stacking. So, can superatoms, like atoms, form crystal by a particular chemical bond? How to bond between superatoms? Are there any strategy models for superatom assembly? To answer those questions, a phenomenological theory named the superatomic molecule theory is introduced which contains understandings of the chemical bonds between superatoms, the building blocks and the assembly strategies. The chemical bonds between the superatoms can be classified into three types, including the super covalent bond, the super hybrid bond and the super non-bonding. A new perspective for the building blocks named isospueratom is introduced, which point out that the isomers of the superatoms can be chosen indiscriminately as building blocks. In addition to assembling superatoms by super valence bonds, other two superatom assembly strategies named superatom network and hybrid superatom network are included. In summary, the superatomic molecule theory contains the understanding of the bonds between superatoms, the thinking of the building blocks, and the consideration on strategies of the superatom assembly. The superatomic molecule theory cannot only be used as the theoretical basis of the superatom assembly, but also be used to understand the stabilities of some special cluster, and provides theoretical guidance for the new clusters design and synthesis.