The effect of the crystal environment on the metalndash;ligand interaction and the ligand field spectrum of CrF3minus;6

摘要

The octahedral CrF3minus;6cluster is studied in two different crystal environments. The available experimental data reveal that the cluster with the largest Crndash;F bond distance is at the same time characterized by the largest value of the spectrochemical strength. This paradoxical fact has been shown to be due to the effect of the two different Madelung potentials. In K2NaCrF6, the central Cr ion is situated at a maximum of the Madelung potential; in CrF3, it is situated at a minimum. For the different crystal environments it has also been shown that theincreasein covalency, that goes with the introduction of correlation, parallels the covalency that is present already at the Hartreendash;Fock level.