The compounds [M(NH3)8]I2 (M = Eu, Yb) were obtained from reactions in anhydrous liquid ammonia solutions as side products. They were characterized by single-crystal X-ray diffraction and found to be isotypic to the compounds [Ca(NH3)8]X2 (X = Cl, Br, I). The coordination sphere of the lanthanoid(II) cations is not square-antiprismatic but much better described as bicapped trigonal-prismatic. In contrast, quantum-chemical gas-phase calculations show the square-antiprismatic coordination polyhedron (point group S8) to be energetically favored over the bicapped trigonal prism and the latter is not even a true local minimum. Obviously, hydrogen bonding and eventually other weak interactions have an impact on the observed bicapped trigonal-prismatic coordination sphere of the [M(NH3)8]2+ cations in the solid state.
|Journal||Zeitschrift fur Anorganische und Allgemeine Chemie|
|Early online date||10 Jun 2020|
|Publication status||E-pub ahead of print - 10 Jun 2020|
|MoE publication type||A1 Journal article-refereed|
- Liquid ammonia
- Quantum-chemical calculations
- Structure elucidation