The following section evaluates the correlation between ML predicted hydricities and QM computed hydricities for each descriptor. From Table , it is seen that the charge shell descriptor with six shells and values sorted according to the Cahn-Ingold-Prelog (CIP) rules best describes the hydricities when looking at MAE and RMSE values. However, we have chosen to proceed with the descriptors with the three numbers of shells. The reason is that the dimensions are up to a factor of 27 higher for six shells. We also expect a better overall performance as three shells better describe the local environment for each atom. We also note that the maximum absolute error is lower for the three-shell descriptor, which may improve the overall performance.