No abstract

Lead hydroxyapatite (PbHAP) particles were prepared by a homogeneous precipitation reaction of Pb(NO 3 ) 2 and (NH 4 ) 2 HPO 4 using acetamide (AA) in aqueous media. The particles obtained under different conditions were examined by various methods, including XRD, FTIR, SEM, ICP, TG-DTA and N 2 adsorption. The crystal phase of the products depended on the concentration of AA ([AA]) and the ageing period (t a ). Large highly crystalline needle-like PbHAP particles were formed by ageing at [AA]=0.4-1.6 mol dm−3 and t a ≥1 day. At [AA]≥3.2 mol dm−3 a mixture of PbHAP and a-Pb 3 (PO 4 ) 2 was generated. The transformation of a-Pb 3 (PO 4 ) 2 to PbHAP in solution at [AA]≥3.2 mol dm−3 was hindered by CH 3 COOH, produced by hydrolysis of AA.is appropriate for the synthesis in a closed system.