Simulation of metal ion coordination sphere in crystals with fluorite structure

摘要

Using quantum-chemical methods, it has been found that the structure of fluorite coincides with the symmetry and coordination number of central calcium atom in the (O (h))-Ca7F14 cluster. The Ca-F and F-F interatomic distances in the cluster are 3-4% shorter than in the crystal. The symmetry of the (O (h))-(ScCa6F14)(+) cluster mimicking the cationic defect after the beta-decay of Ca-45 does not correspond to the energy minimum. The increase in the cation charge from 1.79 to 2.80 a. u. reduces the radius of the first coordination sphere by 0.14 . For ytterbium dihalides, the bond lengths Yb-F 2.344, Yb-Cl 2.897 and the cation charges 1.81, 1.64 a. u., respectively, have been found.