Synthesis of the Bi-doped Apatite-type Phases La10-xBixSi6O27 (x= 0.5, and 1)by Hydrothermal Method

Lanthanum silicate apatites are attracting due to their considerable interest as an electrolyte of solid oxide fuel cells. In this paper, we reported synthesis of two Bi-doped apatites and one undoped one. Apatite were synthesized by hydrothermal at 200°C for 3 days from La2O3, Na2SiO3, and Bi2O3(for Bi-doped). Le Bail refinement of X-ray data showed that all apatites have a hexagonal cell (P 63/m space group). The lattice parameters of La9.5Bi0.5Si6O27 and La9Bi1Si6O27 are a = b = 9.718(1) Å, c = 7.190(1) Å, and a = b = 9.724(1) Å, c = 7.189(1) Å, r. There is increase in lattice parameters with increasing content of Bi.