Characterization of intermediate stages in the precipitation of hydroxyapatite at 37 °C

► Precipitation of hydroxyapatite (HAp) at 37 °C was investigated. ► Low concentrations reagents were used. ► Different initial molar ratios Ca/P (1, 1.33 and 1.67) were studied. ► For Ca/P=1.33, a suspension of HAp nanoparticles stabilized at a pH close to 7. ► Precipitation of ACP and its subsequent conversion to HAp was verified.