Could the lithium bond be classified as the σ-hole bond? – QTAIM and NBO analysis

The lithium bond is analyzed in complexes of ZH3Li and ZF3Li (ZC, Si and Ge) acting as the Lewis acids with HCN and N2 Lewis bases. There are the unique properties of the lithium bond if it is compared with the other non-covalent interactions. For the lithium bond the complexation leads to the decrease of the positive charge of the Li-atom and the increase of its volume while for the hydrogen bond usually the increase of the positive charge of H-atom and the decrease of its volume is observed. The lithium bond may be probably classified as the σ-hole bond. The other properties of the lithium bond are presented and analyzed based on MP2/aug-cc-pVTZ calculations, the quantum theory of atoms in molecules, natural bond orbitals method and the decomposition of the interaction energy.