As a compromise between M06 and M06-HF, M06-2X, with 54% of exact exchange, remarkably improves the agreement of the RDFs with experiments. Despite the first minimum of g OO being a bit right-shifted by ∼0.3 Å, M06-2X shows better peak positions and an improved second coordination shell according to the second peak in g OO . As observed, the agreement with experimental data is not a trivial matter, as the structure of water is the result of the complex interplay between covalent bonds, hydrogen bonds, and vdW interactions. Many-body effects among hydrogen-bonded water molecules can be observed in the first peak of g OO and the second peak of g OH . The region between the first and second peaks of g OO mainly consists of non-hydrogenbonded water molecules that occupy the intershell space between the hydrogen-bonded neighbors. The increased number of water molecules in these intershell regions can partly be attributed to the attractive, non-directional vdW interactions . Therefore, achieving a balance between exact exchange and vdW dispersion at an intermediate length scale is essential for accurately reproducing the densely packed and disordered structure in the intershell regions. As demonstrated by the RDFs, M06-2X captures these correlations with the highest accuracy and is thus capable of describing both hydrogen bonding and dispersion effects. M06-2X was specifically designed with the absence of transition metals in its training set, and focuses on the description of the electron correlation of the main group elements which could be one of the reasons why it performs so well on water compared to M06 for which transition metals were included. M06-HF lacks an adequate amount of correlation to counterbalance the full exact exchange: The second coordination shell has a higher population of water molecules that are not sufficiently drawn out to the intershell region by vdW forces.