To achieve this goal, we first optimized our crystallization conditions using non-radioactive Ba 2+ as a surrogate for Ra 2+ . We selected DB30C10 as the chelator for Ra because it has been used previously to grow single crystals with other large, charge-diffuse metal ions such as divalent samarium (Sm 2+ ), Ba 2+ , and potassium (K + ) , and it bears similarity to the macrocyclic chelators employed in TAT. The Ba1 complex was synthesized using equimolar amounts of Ba(NO3)2 and DB30C10 in H2O or D2O (although compounds may contain either H2O or D2O from synthesis, H2O is used throughout this work for simplicity). To aid in our efforts, tetrabutylammonium tetraphenylborate (Bu4NBPh4, 2 equiv in CH3CN) was added to the reaction solution to promote the exchange of NO3 -for BPh4 -as the charge-balancing non-coordinating counteranion. The BPh4 -anion is commonly used to increase the crystallinity of compounds and adds significant mass to the resulting complex, which is favorable when attempting to crystallize an otherwise small amount of material. Colorless crystals formed after slow evaporation of the solution overnight (see methods) and were identified by scXRD as [Ba(DB30C10)][BPh4]2•MeCN (Ba1). Our initial reaction conditions were subsequently scaled down to a metal content of 330 ng Ba 2+ as Ba(NO3)2, from which we were able to consistently obtain single crystals.