To understand how the different implicit-solvent models behave, a set of 22 molecular balances for which experimental free-energy differences between a key ketone rotation have been determined in Ref. were studied using the the BP86 functional and the SVP basis set (Fig. ). First, classically optimized structures were taken as a starting point for QM optimizations with the SMD implicit-solvent model. The free energies of the optimized structures were evaluated with SMD and openCOSMO-RS. They also served as starting structures for the evaluation with QM-GNNIS, which was used to refine the conformers further before the free energies were estimated. The comparison between the predicted and experimentally observed free-energy differences for molecular balances A1, B1, C1, and D1 is shown in Fig. , and the results for all molecular balances are provided in Fig. -S3 in the ESI. Overall, all implicit-solvent models provide decent agreement between the predicted ∆∆G and the experimental values. To compare the models quantitatively, we calculated the Pearson correlation coefficient (PCC) for all balance / solvent combinations (top panel of Fig. ). While the SMD and QM-GNNIS models show a similar correlation, the openCOSMO-RS model performs significantly worse.