Ab initio investigations on lithium-superhalogen (Li-X) complexes (X = LiF2, BeF3, BF4 and PF6): competition between s-block and p-block anions

In this work, we investigate the formation of Li-X complexes by interaction of Li cation and superhalogen (X) anions belonging to s block (X = LiF2, BeF3) and p block (X = BF4, PF6). We discuss their structures and stabilities using the quantum chemical method at MP2/aug-cc-pVDZ level of theory. Considering polarisable continuum model, solvent effects are taken into account in a polar organic solvent, namely diethyl ether. Our findings establish that electronic and chemical properties of Li-LiF2 and Li-BeF3 closely resemble Li-BF4 and Li-PF6. However, Li-LiF2 may dissociate preferably into LiF salt; Li-BeF3 appears as a close analogue of Li-BF4, which is significantly stabilised by the solvent. Thus, the superhalogen anions possess electronic integrity irrespective of the nature of central atom.