An important inorganic phase for synthetic bone applications, calcium hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)), was prepared as a nano-sized (similar to 50 nm), homogeneous and high-purity ceramic powder from calcium nitrate tetrahydrate and diammonium hydrogen phosphate salts dissolved in modified synthetic body fluid (SBF) solutions at 37 degrees C and pH of 7.4 using a novel chemical precipitation technique. The synthesized precursors were found to easily reach a phase purity >99% after 6 h of calcination in air atmosphere at 900 degrees C, following oven drying at 80 degrees C. There was observed, surprisingly, no decomposition of HA into the undesired beta-TCP phase even after heating at 1600 degrees C in air for 6 h. This observation showed the superior high-temperature stability of such 'biomimetic' HA powders as compared to those reported in previous studies. The former powders were also found to contain trace amounts of Na and Mg ions, originating from the use of SBF solutions instead of pure water during their synthesis. Characterization and chemical analaysis of the synthesized powders were performed by X-ray powder diffraction, energy-dispersive X-ray spectroscopy, Fourier-transform infra-red spectroscopy, scanning electron microscopy, and inductively coupled plasma atomic emission spectroscopy. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.