By focusing on atoms, Fig. reveals that the difficulties in CrO are very likely a feature of Cr more than the bond. Indeed, the Cr atom samples a greater spread in feature space than any of the other atoms shown. Given the lack of potential training data even from other transition metals, it is not surprising that DM21 did not learn how to model Cr bonds from its organic training set. What is remarkable is that atomic Cr converges at all, unlike atomic V and Fe that have similar (but less spread) features.