Influence of foreign metal ions on crystal growth and morphology of brushite (CaHPO4, 2H2O) and its transformation to octacalcium phosphate and apatite

摘要: Abstract Brushite, forming tabular crystals, has been precipitated at 25 °C in the presence of each 14 different di- and trivalent metal ions. The influence these ions micromolar concentrations on solvent-mediated phase transformation brushite to more basic calcium phosphates studied as well. effect additives crystallization was pH-dependent, which could be related or absence amorphous precipitate. In latter case course process followed by recording pH function time. For half kinetic analysis possible showed that crystal growth mechanism is surface nucleation. Edge free energy lowered an additive. Zn favoured aggregates, transition metals with exceptions Mn(II), Co(II) Cu(II) irregular growth. inhibited lateral growth, did Cd Cr(III) low high pH. Most have a marked octacalcium phosphate (OCP) hydroxyapatite (HAP) both cases are strong inhibitors, whereas Pb(II) moderate promotor. Fe oxidation states, Co(II), Mn(II) Sr intermediate transformation. Inhibition may caused adsorbed foreign impeding nuclei poisoning substrate for heterogeneous nucleation, i.e. crystals. Promotion explained formation suitable structure, e.g. apatite/pyromorphite (Ca,Pb)5OH(PO4)3 Pb.