The determination of the calcium to phosphate ratio (Ca/P) in Ca-deficient hydroxyapatite [d-HAP; Ca10−x (HPO4) x (PO4)6−x (OH)2−x ] using X-ray diffraction analysis (XRD) is reported. At temperatures above 700°C HPO4 2- groups are transformed to PO4 3- groups, thereby producing β-tricalcium phosphate [β-TCP; Ca3(PO4)2]. Thus, the deviation from stoichiometry, x, can be calculated from the mass fraction of β-TCP, which in turn can be determined from quantitative XRD analyses. In this study d-HAP powders with various Ca/P ratios were prepared following several procedures. It is shown that the Ca/P ratio determined by quantitative XRD correlates well with that measured by chemical analyses.
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Ishikawa, K., Ducheyne, P. & Radin, S. Determination of the Ca/P ratio in calcium-deficient hydroxyapatite using X-ray diffraction analysis. J Mater Sci: Mater Med 4, 165–168 (1993). https://doi.org/10.1007/BF00120386
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DOI: https://doi.org/10.1007/BF00120386