Experimental and thermodynamic model-predicted melting points for the quinone and hydroquinone datasets are plotted in Figure . We did not observe a large difference between the test set and training set errors for the thermodynamics-based models -the AAE means were within 5 °C of each other, indicating that overfitting is not an issue for the thermodynamic features in the thermodynamic model. and model coefficients are reported in Table . Fitting both dataset models (Equation ) yields coefficients (Table ) consistent with the predicted signs with the exception of al and ar in the hydroquinone model. A lack of diversity in values of al for the molecules available in the dataset may give rise to model bias. Another plausible explanation is that the effect of aliphatic eccentrity on the entropy of melting may lower the entropy of the solid phase more than it lowers the entropy of the liquid phase for the hydroquinones. The aromatic eccentricity ( ar ) also does not appear to be a reliable predictor for the hydroquinones, given that the confidence interval spans negative and positive values. Additionally, we see a larger magnitude for the values of g for the hydroquinone dataset, which indicates stronger dipole-dipole interactions in the hydroquinone dataset. This is expected due to the ability of the hydroxyl groups to form hydrogen bonds, which are stronger than ordinary dipolar interactions. For quinones and hydroquinones, the sign of the coefficient for the molecular symmetry (σ) number a is always negative, as expected. Both quinones and hydroquinones have a positive coefficient for molecular flexibility (τ ), indicating that τ increases the entropy of the liquid phase more than the entropy of the solid phase.