Growth units and nucleation: The case of calcium phosphates

摘要: Abstract Calcium phosphates are precipitated at 37°C from solutions the pH of which ranges 5.0 to 11.0. Despite fact that supersaturations hydroxyapatite HAP, octocalcium phosphate OCP and brushite B often in order HAP⪢OCP⪢B, nucleates more easily than HAP low pH, while mean high pH. These facts cannot be explained, as usually, by only differences surface free energies three solid phases. On other hand, they may explained assuming values kinetic coefficients change a function concentration proper growth units have integrate nuclei either phase. In model we propose, smaller 10 18 orders magnitude pH=6.5, reduce 3 pH=10.0. Accordingly, nucleation is favoured with increasing