Predicted energies and structures associated with the mixed calcium strontium fluorapatites

Atomic scale local density functional simulations and configurational averaging are used to predict the energies and lattice parameters associated with mixed calcium/strontium fluorapatites, CaxSr10−x(PO4)6F2. In particular, the partition of Sr2+ and Ca2+ ions between the 6h and 4f cation sites is established across the entire compositional range. Lattice parameters and lattice volume are also analyzed as a function of Ca2+ to Sr2+ concentration and their cation site distribution. The predicted internal energy of mixing between the end members is used to discuss the available experimental data.

Graphical abstractQuantum mechanical simulations rationalize the distribution of strontium and calcium over 6h and 4f cation sites in fluorapatite across the entire CaxSr10−x(PO4)6F2 solid solution. Lattice parameters and lattice volume are also analyzed as a function of Ca2+ and Sr2+ cation site distribution and concentration.Figure optionsDownload full-size imageDownload as PowerPoint slide