RESUMO
Samples of crystalline hydroxyapatite (HA) with and without the addition of individual Mg(2+), Mn(2+) and Sr(2+) ions and samples with the addition of all three ions simultaneously were prepared using the precipitation method in an aqueous medium. Chemical, structural, spectroscopic and thermophysical analyses of the synthesized samples were conducted. The obtained results indicate that Sr(2+) ions were easily incorporated into the HA crystal structure, whereas it was difficult to incorporate Mg(2+) and Mn(2+) ions into the HA lattice when these ions were individually introduced into the samples. The synthesis of HA with Mg(2+) or Mn(2+) ions is characterized by the formation of HA with a low concentration of doping elements that is outweighed by the amount of these atoms present in less biocompatible phases that formed simultaneously. However, the incorporation of Sr(2+) along with Mg(2+) and Mn(2+) ions into the samples allowed for the synthesis of HA with considerably higher concentrations of Mg(2+) and Mn(2+) in the crystal lattice.