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

Abstract

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.

Keywords:

• lithium–superhalogen complex
• dissociation energy
• solvent-effect
• ab initio study

Additional information

Funding

A.K. Srivastava acknowledges Council of Scientific and Industrial Research, New Delhi, India for providing a research fellowship [grant number 09/107(0359)/2012-EMR-I].