We have also performed a Boltzmann population analysis to get the relative population of each conformer with respect to the most stable one among each category of Ln-PF6 -complexes. To understand the variation of metal charge with the addition of PF6 -and change of the CN, we have also performed a Natural Population Analysis (NPA). By exploring the entire complexation phenomena between RTIL and RE cations, we examined whether the chosen RTIL prefers to bind with the light or heavy RE cations. 50]. The PBE0 functional mixes the Perdew-Burke-Ernzerhof (PBE) and Hartree-Fock exchange energy in a 3:1 ratio, along with the full PBE correlation energy. For all gas and solvent phase geometry optimizations, the def2-svp basis set, developed by Ahlrichs and coworkers , has been used for the main group elements. Lanthanide metals are modeled with the Stuttgart RSC Segmented basis set and ECP with 28 core electrons , which reduces the calculation expense and accounts for scalar relativistic effects. We have also considered the van der Waals interactions through empirical long-range contributions employing Grimme's dispersion (D3) .