Use case 1: Visualizing attributions to free hydration energy predictions using SHAP values In this use case, we explored the predictions of a model that was trained on the hydration free energy of a set of compounds. Hydration energy is one component in the quantitative analysis of solvation. It is a particular special case of water and describes the amount of energy released when one mole of ions is covered by water molecules. If the hydration energy is greater than the lattice energy, then the enthalpy of solution is negative (heat is released), otherwise it is positive (heat is absorbed). The more negative the hydration free energy, the more soluble in water the compound. Hydration free energy is an important physicochemical property to assess properties such as the bioavailability of small molecules.