An important inorganic phase of synthetic bone applications, calcium hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)), was prepared as a single-phase ceramic powder. Carbonated HA powders were formed from calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts dissolved in aqueous 'synthetic body fluid' (SBF) solutions, containing urea (H2NCONH2), at 37 degrees C and pH of 7.4, by using a novel chemical precipitation technique. These powders were also found to contain trace amounts of Na and Mg impurities in them, originated from the use of SBF solutions, instead of pure water, during their synthesis. The characterization and chemical analysis of the synthesized powders were performed by powder X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FT-IR), and inductively-coupled plasma atomic emission spectroscopy (ICP-AES). (C) 1999 Elsevier Science Ltd. All rights reserved.