, and Li + decreases from 83% to 75% to 62%, respectively. Correspondingly, the proportion of N atoms increases from 12% to 23% to 29% in the K + to Na + to Li + sets (Supporting Information Figures and). Because the majority of complexes are energetically most favorable with their natively coordinated ion, this suggests the larger ions such as K + prefer O coordination and smaller ions such as Li + prefer N coordination. This is also consistent with our differential binding energies, where the 16 complexes in the native Li + set that have the strongest enthalpic penalty for exchange to the alternative ions (i.e., show highest selectivity to bind to Li + ) all are at least partially coordinated by N (Supporting Information Figure ). This is despite the fact that the most common coordinating atom (on average 62% of the coordinating environment) in the Li + set is O (Supporting Information Figure ).