| Abstract: | About Irontribromide: Equilibrium Studies, Crystal Structure, and Spectroscopic Characterization Iron(III) bromide has been thoroughly characterized by thermal, x‐ray, and spectroscopic investigations on crystalline FeBr3 samples which were grown by CVD at higher bromine pressures. The thermodynamical data for equilibria between FeBr2, FeBr3 and Br2 obtained by pressure measurements are in agreement with chemical vapor transport experiments and confirm the statements of the literature to a high extent. Refinement of the crystal structure with single crystal data (a = 6.937(1) Å; c = 18.375(4) Å Z = 6) confirms the assignment to the rhombohedral BiI3 type (Spgr. R‐3). On this base, the UV‐VIS, FTIR and Raman spectra were interpreted. The totally symmetric stretching mode of FeBr3 (173 cm–1) in comparision to FeCl3 (282 cm–1) was found lower as to be expected by consideration of the mass influence alone. Impedance measurements on pure samples under ambient conditions showed low electronic conductivity (10–8 Ω–1 cm–1) but high capacitive contributions, resulting from displacement polarisation. The investigations gave no hints for neither a mixed valent “Fe3Br8” nor a substantial phase width of the solid compounds FeBr2 and FeBr3. |
