Notably, adding the elements as features did not affect the accuracy of the model (entries 1 vs. 2; median MAE = 0.68 vs. 0.69) suggesting that the necessary atom-based information is captured by the variables included to account for inductive and resonance effects (e.g., electronegativity, bond polarization). In fact, when the non-categorical atom and bond features are removed and replaced by elements, the error increased (entries 1 vs 4, median MAE = 0.73). However, either elements or atomic properties are needed as shown with entry 3 (median MAE = 0.80) compared to entries 1 and 4. Overall, our approach provides models (MAE = 0.68 ± 0.02) which are significantly more accurate than the RF and XGB baseline models mentioned above (MAE > 0.9).