Effective nuclear charge of an ion

An analysis of the effective nuclear charge of ions based on linear relationships of the reciprocal of an ionic radius or the square root of ionisation energy and the nuclear charge of the ion has been carried out. It has been demonstrated that the effective nuclear charge of an ion is significantly different from its formal charge. The obtained character of the relationship indicates that the postulated parameter can be employed to determine differences in properties of ions. It has also been shown that the differences occurring in the calculated effective nuclear charges of the ion permit one to differentiate its states. Namely, values based on ionisation enthalpy characterise ions of a given coordination number in a crystal lattice.