Rietveld Refinement of the Crystal Structure of Hydroxyapatite Using X-ray Powder Diffraction

Abstract

The stoichiometric hydroxyapatite, Ca10(PO4)6(OH)2 is prepared by an aqueous precipitation method at room temperature, the main reactants were Ca(OH)2 and H3PO4 without addition of ammonia solution. The sample was analyzed by Fourier transformed infrared spectroscopy (FTIR) which reveals the presence of a small amount of carbonate due to absorbance of carbon dioxide from the air during synthesis process. The crystal structure was carried out by X-ray powder diffraction data and the Rietveld method using FullPROF software. We confirmed that this material has a hexagonal structure (space group P63/m; Z = 1). Unit-cell parameters with higher precision (a = b = 9.4159(4) Å , c = 6.8819(3) Å, α = β = 90°; and γ = 120°).