The test set was chosen to include measurements of ( ), Δ ( ), , and Δ as in the training set. Additionally, a set of non-aqueous solvation free energy (Δ ) measurements for the same moieties included in the training set was sourced from the MNSolv database . Unlike the training set, we do not require that all pure substance and binary mixture measurements in the test set must be sourced from the same set of molecules. Instead, given the limited amount of diverse Δ ( ) and Δ data for the selected moieties, focus was given to selecting as diverse a test set as possible which maximally exercised the re-trained parameters. Data points from pure substances included in the training set were excluded from the test set, as well as mixture data points from mixtures included in the test set. The test set did include binary mixtures for which one of the two components was present in the training set; for example, a mixture of ethanol and pentanol would be permissible in the test set even if data points for ethanol/propanol and butanol/pentanol were both included in the training set. This expands the test set to types of mixtures that were not included in the training set; for example, mixtures containing either an alcohol or ketone are in the training set, but alcohol/ketone mixtures are only included in the test set. The set was also selected to contain substances as distinct as possible from the training set, and from other molecules in the test set. Mixtures including carboxylic acids were not included in the test set due to low data availability.