The Samsonov Configurational Model: Instructive Historical Remarks and the Extension of Its Application to Substituted Hydroxyapatite.

The Russian-Ukrainian scientist, G. V. Samsonov left an enormous legacy in materials science, even though a large portion of his and his group's work remained hidden behind the Iron Curtain. One of his crowning theoretical contributions that received but a slight tidbit of resonance in the west was the configurational model of the solid state based on the statistical weight of atoms with stable configuration (SWASC). Only a handful of papers employing this model were published in the western journals since the model was developed, in 1965. Here, the configurational model was tested for its ability to explain the effects of divalent transition elements on solubility of hydroxyapatite when they acted as dopants in it. It is shown that the SWASC values for half-filled d orbitals of transition elements in the ± 5 pm range of ionic radii centered around iron do correlate monotonously with the solubility change induced by the dopant ions relative to the solubility of stoichiometric hydroxyapatite synthesized and analyzed under the same conditions when the solubility values are extrapolated to identical atomic ratios between the dopant ions and the constitutive calcium ions. The effect of SWASC, however, competes with that of the dopant concentration, producing a complex plexus of mutually antagonistic effects. With this work, it is hoped that the interest in the work of G. V. Samsonov and the generation of his Soviet and Yugoslavian scientific contemporaries gets revived and their legacy in the west popularized. [ABSTRACT FROM AUTHOR]