The preservation of the individuality of 3d atoms in a solid
  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. 
R.J. Radwanski and Z.Ropka