Solvated Ba2+ with square antiprismatic and cubic coordination geometries

Solvated metal cations represent fundamental and crucial mononuclear species in various research fields, including chemical, physical, and biochemical studies. However, controlling their coordination geometry poses a significant challenge. In this study, we successfully synthesized and structurally characterized solvated Ba2+ complexes. The coordination geometry of [Ba(CH3CN)8]2+ was a thermodynamically stable square antiprism, while that of [Ba{(CH3)2CO}8]2+ exhibited a rare cubic structure, demonstrating a unique approach to controlling coordination geometry solely by altering crystallization solvents.