Driven by the long-standing challenge of chelating Ra 2+ and the desire to transform Ra into a targeted radiotherapeutic agent for a range of cancers, we sought to shed new light on the structural chemistry of Ra 2+ through single crystal X-ray diffraction (scXRD). This technique allows one to gain a complete picture of bond distances and angles, conformation, geometry, strain, and key binding interactions within a structure, descriptors that ultimately underly and dictate the overall stability of a metal-ligand complex. Until now, information on the structure and bonding of Ra 2+ complexes using this traditional characterization tool has not been accessible. Here, we describe how we overcame the hurdles of working with a macroscopic quantity of Ra to attain the first single crystal structure containing the Ra 2+ ion, to the best of our knowledge. This structure was obtained using the macrocyclic crown ether dibenzo-30-crown-10 (DB30C10). Analysis of the Ra 2+ complex in comparison to DB30C10 complexes of the smaller alkaline earth ion Ba 2+ reveals significant differences in their structural conformation and bonding interactions, underscoring the divergent chemistry of these congeners. The insight garnered here into the complexation behavior and preferences of the Ra 2+ ion will be valuable in establishing ligand design principles that promote the stabilization of 223 Ra 2+ for TAT. It also serves as guidance for handling, synthesizing, and crystallizing 226 Ra 2+ complexes to support future solid-state characterization efforts by researchers for this radioactive ion.