Stability and Aromaticity of Some Superatomic Compounds Al3-X (X = F, LiF2, BeF3, BF4)

This work makes use of Al-3 clusters and fluorine atom or its superhalogens (LiF2, BeF3, BF4) as the basic unit to design a new series of Aluminum clusters-superatomic compounds Al-3-X (X = F, LiF2, BeF3, BF4) theoretically. The most stable orientation for Al-3-F can be found when one of the aluminum atoms in Al-3 ring is adjacent to fluorine atom, whereas the best orientation between Al-3 and superhalogen (LiF2, BeF3 or BF4) exists when one of the aluminum atoms in Al-3 ring has the shortest distance with F-F bond in superhalogen (LiF2, BeF3 or BF4) ring. Large frontier molecular orbital energy gap and binding energy in these compunds, as well as Atoms-In-Molecule theoretical analysis prove that there is good stability between Al-3 and fluorine atom or its superhalogens (LiF2, BeF3, BF4). Additionally, aromaticity of Al-3-X compound has been confirmed by means of Nucleus-independent chemical shift (NICS) calculation of Al-3 ring in these compounds. This work can provide useful information for new materials synthesis, as well as fabrication of new superatomic compounds.