Mg2 + and Mn2 + ions have a great difficulty being stabilized in the apatite lattice.
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Sr2 + ions can stabilize Mg2 + and Mn2 + in the hydroxyapatite structure.
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Except for Mn2 +, Sr2 + and Mg2 + obstruct the release of CO2.
Abstract
Samples of crystalline hydroxyapatite (HA) with and without the addition of individual Mg2 +, Mn2 + and Sr2 + 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 Sr2 + ions were easily incorporated into the HA crystal structure, whereas it was difficult to incorporate Mg2 + and Mn2 + ions into the HA lattice when these ions were individually introduced into the samples. The synthesis of HA with Mg2 + or Mn2 + 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 Sr2 + along with Mg2 + and Mn2 + ions into the samples allowed for the synthesis of HA with considerably higher concentrations of Mg2 + and Mn2 + in the crystal lattice.
Graphical abstract
Sr2 + ions were easily incorporated into the HA lattice, whereas Mg2 + and Mn2 + ions were hardly retained in the HA structure after heating to 1000 °C when they were individually incorporated in the samples. Nevertheless, co-substitution with Sr2 + ions allowed for better fixation of the Mg2 + and Mn2 + ions into the HA lattice.
