Thermodynamic Modeling of Integration of Strontium into Bone Tissue Hydroxyapatite

Abstract

Th is study analyzes the Ca 10 (PO 4 ) 6

New Solid-Solutions of Substitution Strontium (Sr) for Lead (Pb) in Apatite Structure

“…In addition to the ionic nature of the Na -O, Sr -O bonds and the covalent nature of the Pb -O bond, the most likely situation is when Na + and Sr 2+ ions are localized in the M1 cationic position and Pb 2+ ions are localized in the M2 cationic position. 39,40 When refining Pb (8-x) Sr x Na 2 (PO 4 ) 6 crystal structure, different variants to fixate the occupations of cations M (1) and M (2) positions were used, and "adequate" results were obtained in the following cases: Assumption 1: in the structure of solid solution Pb (8-x) Sr x Na 2 (PO 4 ) 6 sodium atoms are distributed in the same way as in the Pb 8 Na 2 (PO 4 ) 6 structure, and the occurrence of strontium ions does not affect the redistribution of sodium ions; Assumption 2: Sr 2+ ions are localized only in position M (1) of apatite structure, and the Na + and Pb 2+ ions are distributed between two cation sites. It should be noted that the given assumptions (the position M (1) is occupied only with Na + and Sr 2+ ions and Na + ions or Sr 2+ ions are localized exclusively in the М (2) position in the compositions with x = 2.00 and 2.75) did not give a positive result in calculations.…”