Sol–gel synthesis and characterization of Sr/Mg, Mg/Zn and Sr/Zn co-doped hydroxyapatites

•Sr/Mg, Mg/Zn and Sr/Zn co-doped hydroxyapatites were prepared by sol–gel route.•The crystallinity decreases gradually with increasing amount of the co-dopants.•A gradual reduction in the lattice parameters was observed with increasing amount of co-dopants.

In the present work, a series of hydroxyapatite (HAp) samples co-doped with Sr/Mg, Mg/Zn, and Sr/Zn were synthesized using sol–gel method. The formation of the HAp phase was found to be in the range of 93.0–97.4%. Compared to the undoped HAp, with increasing amount of the co-dopants, a gradual decrease in the values of the crystallinity percent, lattice parameters and volume of the unit cell decrease were observed. B-type carbonate substitution was detected for all the samples. All the samples had the morphology consisting of the nanoparticles.