Synthesis and characterization of barium tetrafluoridobromate(III) Ba(BrF₄)₂

Alkali and alkaline earth metal tetrafluoridobromates M^IBrF₄, M^II(BrF₄)₂ (M^I = Na-Cs, M^II = Sr, Ba) can be synthesized from the respective fluorides and BrF₃. The reaction of BaF₂ with liquid BrF₃ under Freon-113 leads to the formation of Ba(BrF₄)₂ as a colorless microcrystalline powder. Here, we discuss its formation kinetics and thermodynamics. The compound crystallizes in the tetragonal space group I$\bar {4}$ with a = 9.65081(11) Å, c = 8.03453(13) Å, V = 748.32(2) ų, and Z = 4 at 27 C, and it is isotypic to Ba(AuF₄)₂. The structure contains square planar BrF₄ ^- anions. The compound is stable at ambient conditions excluding moisture and at temperatures up to approximately 200 C. Solid-state computational calculations of the Raman and IR spectra are in good agreement with the experimentally obtained ones, and in combination with its powder X-ray diffraction pattern, density measurement, thermodynamics, elemental and EDXRF analyses, this shows that the compound is pure.