The Maximum Hardness Principle and the Composition of Zn(II) and Cd(II) Tetrafluoroborate Complexes with Nitrogen-Containing Organic Bases

The hardness/softness parameters of the central complexing ion, the donor nitrogen atom of the ligand, and the coordination bond were calculated for zinc and cadmium tetrafluoroborate complexes with nitrogen-containing organic bases of various composition (both experimentally determined and hypothetical). On the basis of the quantitative estimate of the hard/soft characteristics of the whole series of the coordination compounds considered, it was found that the hardest parameters are inherent in the complexes isolated in a pure state by a preparative method.