Abstract: | On Hexagonal Perovskites with Cationic Vacancies. VII. Vibrational Spectroscopie investigations on the Rhombohedral 12 L-Stacking Polytypes Ba4BII(Re2□O12) and Ba4B □1/3 (Re2 □ O12) For the rhombohedral 12 L stacking polytypes Ba4BII(Re2□O12) and Ba4B□1/3(Re2□O 12), space group R3 m, sequence (3)(1), the lattice consists of groups of three face sharing octahedra with the composition Re2□O12. They are isolated from each other by the Ba and B ions.The vibrational spectra are interpreted according to the factor group analysis. For the Re2□O12 unit (symmetry D3d) the results of a complete vibrational analysis and the calculation of the force constants are reported. |