The study of the complexation between Nd(III) and RTIL starts with the coordination of three PF6 -anions forming a 9-coordinated complex ( Nd 39CN), where all PF6 -anions are in tridentate coordinations, which we denote as a (3+3+3) arrangement around the Nd(III) center. The Nd-F bond distances vary between 2.41-2.49 Å in RTIL medium and the associated 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - is calculated to be -207.0 kcal/mol. The addition of four PF6 -anions around the Nd(III) center makes the entire picture a bit complicated as a total of four differently coordinated complexes, ranging from 9-12 coordinate, have been optimized. In the 9coordinated complex ( Nd 49CN), a (3+2+2+2) arrangement of four PF6 -anions have been identified, where one PF6 -coordinates as tridentate ligand and the other three are in a bidentate coordination, represented by one '3' and three '2' numbers. With the increase of the CN from 9CN, the bidentate coordination changes to tridentate coordination one by one, forming a maximum 12CN complex via the formation of 10CN and 11CN complexes. As evident from the bond length values in Table , neither the Nd-F bonds for tridentate coordination nor the bidentate coordination varies too much upon changing the CN. In terms of the 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - values (Table ), it is observed that with the increase of CN, the 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 Further, we have attempted to add a fifth PF6 -to the first solvation shell. Here also, we have identified differently coordinated complexes like Nd-4-PF6 -complexes. One of the new observations is that for 9, 10 and 11-coordinated complexes, more than one isomer with different combinations of tri, bi-and monodentate coordination of PF6 -has been optimized. In the case of 9CN, two geometries have been optimized, the first one is the (3+2+2+1+1) arrangement of PF6 -anions ( Nd 59CN-1), and the second one is (2+2+2+2+1) arrangement ( Nd 59CN-2). As shown in Table , in the RTIL medium, the tridentate Nd-F bond lengths vary between 2.49 -2.51 Å for the former one. The bidentate Nd-F distances is between 2.40-2.45 Å for both 9CN complexes, and the monodentate Nd-F distances are almost similar for both 9CN complexes. In terms of 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - , the Nd 59CN-2 complex has been identified as more stable than the Nd 59CN-1 by 2.3 kcal/mol in RTIL medium. For 10CN, a total of three complexes, Nd 510CN-1, Nd 510CN-2 and Nd 510CN-3 with respective PF6 -arrangements of (3+3+2+1+1), (3+2+2+2+1), (2+2+2+2+2) have been identified. For all three differently coordinated Nd-F bonds, the calculated distances are almost the same for Nd 510CN-1 and Nd 510CN-2 complexes, however for Nd 510CN-3 complex, where all PF6 -anions are in bidentate coordination, the Nd-F bonds are slightly longer than the aforementioned 10CN complexes. The trend of 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - values for the 10CN complexes is as follows: Nd 510CN-3 (-262.7 kcal/mol) > Nd 510CN-2 (-261.1 kcal/mol) > Nd 510CN-1 (-257.0 kcal/mol). In the case of 11CN, two differently coordinated complexes, (3+3+2+2+1) and (3+2+2+2+2), defined as Nd 511CN-1 and Nd 511CN-2 respectively have been optimized in the gas phase. Here, we are unable to optimize the Nd 511CN-1 complex in the RTIL medium. As evident from Table , for the Nd 511CN-2 complex, in the gas phase, one of the tridentate Nd-F distances is much longer (2.86 Å) than the other Nd-F distances (2.49 Å), making the complex partially 11CN. However, in the RTIL, the distance reduces subsequently, and all tridentate Nd-F distances vary between 2.52-2.60 Å, although the variation is larger compared to other Nd-5-PF6 -complexes discussed so far. Minimization of the steric and electronic repulsions between the coordinated fluorides with the increase of CN can be the reason behind this extended Nd-F distance. Similar to other Nd-5-PF6 -complexes, the bidentate Nd-F distances vary between 2.44-2.50 Å in RTIL medium. In terms of 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - , the Nd 511CN-2 complex has a 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - value of -266.0 kcal/mol in RTIL medium. In the case of the 12CN complex with a (3+3+2+2+2) arrangement of PF6 -around the Nd(III) cation, the Nd-F bond distances for the 12CN complex in RTIL medium are between 2.55-2.57 and 2.47 Å for tri-and bidentate PF6 -coordination, respectively. Among all Nd-5-PF6 -coordination complexes, the 12CN complex has the highest 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - value of -266.6 kcal/mol. Here also, the increase of 𝐵𝐵𝐵𝐵 𝑃𝑃𝑃𝑃 6 - from Nd-4-PF6 -complexes to Nd-5-PF6 -complexes in both the medium confirms the feasibility of a fifth PF6 -addition.