We have explored the complexation phenomena of two RE cations, Nd(III) and Yb(III) with RTIL considering all possible modes of PF6 -bindings. The complexation of the RE cations with RTILs are compared based on the geometrical parameters and calculated BE values. Although we have explored the complexation phenomena in both gas and RTIL medium, focus was given on analyzing the BE in RTIL medium as it gives a more realistic picture of binding. The addition of PF6 -to the RE cations starts with three and goes until we achieve the highest BE complex in the RTIL medium. The BE values for the first solvation shell complexes in the RTIL medium are tabulated in Tables and for Nd(III) and Yb(III) complexes, respectively. The Boltzmann distribution and NPA charges are shown in Tables . For the second solvation shell complexes, the BE values are given in Table . The optimized geometries of 6-PF6 - and 7-PF6 -complexes in RTIL for Nd(III) and Yb(III) are depicted in Figures and, respectively. The optimized geometries of the second solvation shell complexes in RTIL are shown in Figures and for Nd(III) and Yb(III), respectively. The gas phase BE values are given in the supporting information. The discussion and conclusions are based on the complexation in the RTIL medium.