A novel nitridogallate fluoride LiBa5GaN3F5 – Synthesis, crystal structure, and band gap determination

LiBa5GaN3F5 was obtained as red crystals by reaction of Ba, Ga, NaN3 and EuF3 in a Na/Li flux at 760 °C in weld-shut tantalum crucibles. The crystal structure (Pnma (no. 62), a = 15.456(3), b = 5.707(1), c = 12.259(3) Å, Z = 4) was solved on the basis of single-crystal X-ray diffraction data. In the solid there are trigonal planar [GaN3]6− ions and zigzag chains of vertex sharing LiF6 octahedrons surrounded by Ba2+ ions. Optical measurements and calculations of the electronic structure revealed a band gap of ≤1.9 eV. According to the calculations, the observed transition occurs from a nitrogen state into a hybrid Ba/N state.

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