  On basis of analysis of experimental results for more than 200 compounds with
3d and 4f elements we conjecture that atoms with unfilled 3d and 4f shells
preserve much of their atomic properties, manifested by the discrete electronic
structure, even then when they become the part of a solid. As a consequence,
electronic and magnetic properties of the 3d-ion containing compounds are
strongly affected by the existence of the atomic-like crystal-field fine
electronic structure.
