Flux crystal growth of a new BaTa2O6 polymorph, and of the novel tantalum oxyfluoride salt inclusion phase [Ba3F]Ta4O12F: Flux dependent phase formation

A new hexagonal polymorph of BaTa2O6 and a novel salt inclusion phase, [Ba3F]Ta4O12F, were obtained via high temperature flux crystal growth using mixed alkali chloride/alkali fluoride fluxes. [Ba3F]Ta4O12F crystallize in the tetragonal space groups P6/mmm P42/mnm, respectively. The structure consists TaO6 octahedra that edge-share equatorial O(2) to form Ta2O10 dimers further connect 3D containing channels which barium cations are located. morphology this is substantially different from those three previously reported polymorphs BaTa2O6. slightly zig-zagging chains trans corner-sharing (via O(3) O(4)) corner-share their O(1) O(5) oxygens with TaO5F create framework for Ba3F inclusion. stability was assessed DFT calculations. (ΔfH0 K −2825.11 ​kJ/mol) has higher energy than other known phases 49.17 ​kJ/mol orthorhombic polymorph.