The solid solutions in the system of Pb and Sr hydroxyapatite, Sr(10-x)Pb(x)HAp (x = 0-10), were successfully synthesized by high-temperature mixing method (HTMM) at 160 degrees C for 12 h under hydrothermal conditions. The samples were characterized by X-ray diffraction, chemical analysis and electron microscopic observation, and the site of the metal ions in the solid solutions was analyzed with the Rietveld method. The lattice constants, both a and c, of the solid solutions varied linearly with Pb content. It was found that Pb ions in the solid solutions preferentially occupied the M(2) site in the apatite structure. HTMM gives Sr-Pb HAp solid solutions much better crystallization. However, due to the formation of intermediate compound of Pb(3)O(2)(OH)(2) in the Pb(NO(3))(2)center dot 4H(2)O solution before mixing with (NH(4))(2)HPO(4) solution at 160 degrees C, HTIVIM causes the decrease of crystallization of the samples with high Pb content. (C) 2008 Elsevier Ltd. All rights reserved.