• nH2O (n ≤ 6) was transferred to a 20 mL glass scintillation vial which was then placed into the antechamber of an argon atmosphere glovebox and left under vacuum for 40 minutes. Once inside the glovebox, the AmI3 • xH2O powder was dissolved dropwise in acetonitrile with gentle stirring until completely dissolved. A pale-yellow solution formed. Separately, the cis-syn-cis isomer of dicyclohexano-18-crown-6 (7.8 mg, 0.021 mmol) was dissolved in in THF by dropwise addition of the solvent. Addition of the crown ether to the solution containing 243 Am resulted in a more intensely yellow colored solution. The solution was transferred to a 6 mL shell vial that was inserted into a 20 mL scintillation vial. The outer scintillation vial was filled to 75% capacity with diethyl ether and capped for vapor diffusion. Colorless, thin plate crystals of [Am(cis-syn-cisdicyclohexano-18-crown-6)(H2O)(CH3CN)I]I2 • CH3CN formed overnight in low yield (< 10%).