The interaction between the aluminum trimer and representative (super)halogens X (X = F, LiF 2 , BeF 3 , BF 4 ) and (super)alkalis M (M = Li, FLi 2 , OLi 3 , NLi 4 ) has been theoretically investigated at the MP2/6-311+(3df) level. Various geometrical structures were obtained for the resulting Al 3 -X and Al 3 -M superatom compounds, respectively. Natural bond orbital analysis reveals that the Al 3 moiety exists in a cationic state in Al 3 -X while in an anionic state in Al 3 -M compounds. And the charge transfer between Al 3 and (super)atoms is found to be enhanced in either polar or nonpolar solvent. The studied superatom compounds feature large bond energies, binding energies, and HOMO-LUMO gaps, which not only reflect their stability but indicate strong interactions between Al 3 and (super)atoms. Although the solvent effect is not significant for the stability of Al 3 -X, the Al 3 -superalkali compounds can be better stabilized in the presence of solvent molecules. In addition, these superatom compounds exhibit aromaticity both in the gas phase and in solution.
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