where X is a coordinating atom, d denotes distance, r ion denotes the ionic radius of the ion and r X denotes the covalent radius of the coordinating atom. For each complex, we take the average d rel of all coordinating atoms. While larger ions predictably have larger coordination numbers, the relative ion-coordinating atom distances when normalized for relative ion sizes are surprisingly smaller for larger ions. Smaller but distinct differences in distributions are also observed for coordinating atom charge and ESP, which highlight the preferred electronic behavior of the coordinating environment for different ions. To assess the selectivity of each of the complexes, we compare properties of complexes when bound to the ion they natively contained in the CSD to properties when bound to the two other ions. This will also enable the development of ML models that can potentially learn the difference between these quantities more efficiently than learning to predict the absolute quantities.