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.

The adsorption of bis­(acetylacetonato)­Cu­(II) on monoclinic scheelite bismuth vanadate forms an O2-bridged dimer complex on the surface resembling hemocyanin in the biosystems (Cu­(acac)2/ms-BiVO4). Visible-light irradiation of Cu­(acac)2/ms-BiVO4 in ethanol aqueous solution gives rise to a two-electron oxygen reduction reaction, whereas unmodified ms-BiVO4 is entirely inactive. The replacement of Cu­(acac)2 by bis­(hexafluoroacetylacetonato)­Cu­(II) drastically enhances the photocatalytic activity to yield H2O2 with an external quantum yield of 0.47% at λex = 470 nm. Electrochemical measurements show high selectivity (∼100%) for the two-electron reduction of O2. The compatibility of the high photocatalytic activity and selectivity can stem from the charge separation enhancement via the interfacial electron transfer from ms-BiVO4 to the surface complex and its O2-enriching effect near the ms-BiVO4 surface and excellent electrocatalysis for two-electron ORR.

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A triangular tungsten(IV) aqua ion with sulfur bridges, W3O2S24+ has been prepared and characterized. X-ray structure analysis of a derivative complex, [W3O2S2(Hnta)3]2−(H3nta = nitrilotriacetic acid) has revealed that its core is of structure of W3(μ2-O)2(μ2-S)(μ3-S). The electronic spectrum of the aqua ion has an absorption peak at 506 nm (ε = 381 M−1 cm−1 per trimer; 1 M = 1 mol dm−3).