The top left and top right panels of Fig. show scatter plots of the two angles for DFO and 4HMS, respectively, obtained from independent configurations sampled along the trajectory at the position of the free energy minimum. The colors correspond to different hydroxamate groups (group1-group3 for DFO and group1-group4 for 4HMS). Above and on the right side of each scatter plot, the probability distributions of the corresponding angles are also shown. In the case of DFO, we see that the angular distributions of group1 and group2 (the ones interacting with Zr 4+ ) are similar; for both groups, the peaks of the probability distributions are located at ≃ 1.5 radians for Zr 4+ -O-C angles and at ≃ 2.8 radians for Zr 4+ -O-C angles. Note that the peak positions do not correspond to the angles of the DFT-optimized structure (shown as a solid green circle in the left panel). On the other hand for group3, which doesn't interact directly with Zr 4+ , the distributions are flat, highlighting that this part of the DFO molecule has no preferred group-orientation. Since this group is next to a positively charged ammonium group, it prefers to be solvated and this, in turn, is more favorable than binding with the Zr 4+ .