Polynuclear Li12F13 − anion as a steric shielding agent with respect to selected metal ions

Marcin Czapla

doi:10.1007/s00214-016-1992-8

Abstract

Polynuclear superhalogen anion Li12F13 − and its ionic complexes formed by the interaction with selected metal ions (i.e., Li12F13 −Na+, Li12F13 −K+, Li12F13 −Mg2+, and Li12F13 −Zn2+) are proposed and investigated on the basis of ab initio calculations. The thermodynamic stability, vertical excess electron detachment energy, and binding energies between ionic components were examined and discussed. The Li12F13 − anion has been proved stable against fragmentation and its vertical electronic stability was found to approach 10 eV. Due to its specific equilibrium structure that resembles a molecular basket, the Li12F13 − anion was found capable of trapping positively charged metal ions inside to form strongly bound ionic complexes. The large values of binding energies predicted for the Li12F13 −Na+, Li12F13 −K+, Li12F13 −Mg2+, and Li12F13 −Zn2+ systems and their specific equilibrium structures indicate that the Li12F13 − anion can be useful as a steric shielding system which protect the metal ions from the interaction with the surroundings.

Highlights

Strong electron acceptors commonly called “superhalogens” were originally proposed and studied by Gutsev and Boldyrev [1]
The superhalogens were defined as a group of compounds matching the MXk+1 formula and characterized by the electron affinity (EA) higher than that of the chlorine atom (EA = 3.62 eV) [2]
It implies that superhalogens form very strongly bound and thermodynamically stable molecular anions [3,4,5] which are characterized by the enormous values of vertical electron detachment energies (VDEs) approaching 14 eV in certain cases [6, 7]

Summary

Introduction

Strong electron acceptors commonly called “superhalogens” were originally proposed and studied by Gutsev and Boldyrev [1]. The superhalogens were defined as a group of compounds matching the MXk+1 formula (where M is a metal atom having the maximal formal valence k, while X corresponds to the halogen atom) and characterized by the electron affinity (EA) higher than that of the chlorine atom (EA = 3.62 eV) [2] It implies that superhalogens form very strongly bound and thermodynamically stable molecular anions [3,4,5] which are characterized by the enormous values of vertical electron detachment energies (VDEs) approaching 14 eV in certain cases [6, 7]. It should be mentioned that some recent works revealed novel superhalogen applications in Li-ion batteries, solar cells, and hydrogen storage materials [24,25,26,27]

Methods

Results

Conclusion