Within these settings, we have shown how various factors can push the limits of MP2 calculations with PWs. The first factor consists of truncating the virtual space thanks to an analytical extrapolation (Eq.11), the second relates to the reduced number of PWs necessary to expand the pair densities and, finally, the last refers to the choice of an efficient Coulomb operator for treating isolated systems and correlation energies. Thanks to these findings, it has been made possible to access the MP2 interaction energies of systems with up to ∼100 electrons that are listed in Table of the Supplementary Material. Convergence was achieved by progressively expanding an orthorhombic cell (r x,y,z = 1.2, 1.4, 1.6, 1.8 and 2.0, 2.2 when possible) with the MT Poisson solver. The HF components were retained when no variations larger than 0.01 kcal/mol were measured, while MP2c contributions were extrapolated first via Eq.38 and then Eq.43. Standard deviations due to this extrapolation procedure are also reported in Table and do not exceed 0.05 kcal/mol for energies spanning a range from -0.50 to -20.19 kcal/mol. and the mean absolute error (MAE) in (b), respectively. Dots represent outliers that are located further than 1.5 times the interquartile range from respectively the first and third quartiles (i.e. the limits of the rectangular boxes).