Supplementary Information

The supplementary material accompanying this article contains results for the solution density, lattice den-sity, and lattice energy for Na-CG-2020 model (and comparison to prior studies), explanation of the soft-core potential used for ion-pair insertions with DLM/BK3-typemodels, details of uncertainty calculations for solubilities and crystal free energies, final parameter sets forthe methane-water optimization, details about a typical iteration of our optimization methodology, and the final parameters sets obtained after optimizing the four DLM/BK3 model variants.