| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1330089 | Journal of Solid State Chemistry | 2013 | 6 Pages |
The structure of Ca8.4Bi1.6(PO4)6O1.8, isostructural with Fluoroapatite, was determined by X-ray powder diffraction methods. The results of Rietveld refinement revealed that the formula of this compound is [Ca4]4f[Ca4.4Bi1.6]6h(PO4)6[O1.8]2a, space group P63/m (a=9.468 (3) Å, c=6.957 (3) Å). A total substitution of Bi3+ ions in the (6h) sites was related particularly to the high polarizability of the Bi3+ ion compared to Ca2+.The observed frequencies in the Raman and infrared spectra were explained and discussed on the basis of unit-cell group analyses and in comparison with Fluoroapatite and other oxyapatites. The ionic conductivity over a wide range of temperature was investigated according to the complex impedance method. The highest overall conductivity values were found at σ700 °C =5.03×10−7 S cm−1 and Ea=0.50 eV.
Graphical abstractThe final Rietveld refinement plot of the Ca8.4Bi1.6 (PO4)6O1.8.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The Rietveld refinement revealed that the formula of this compound is Ca8.4Bi1.6(PO4)6O1.8. ► Vibrational spectroscopy supports the high symmetry P63/m space group for this apatite. ► This apatite contained channels where oxygen ions were located in 2a sites. ► The possibility of anionic conduction along these channels was considered.
