Abstract
Dipole and quadrupole polarizabilities and shielding factors for 18-electron closed-shell ions from Cl to Ca++ have been calculated following the self-consistent perturbation procedure. Interpolation relations correlating these quantities with the radii of maximum electron density of the ions have been obtained. These relationships may be used to assess the true polarizabilities and nuclear shielding (or antishielding) factors for such ions in actual crystals.