Synthesis and crystal structures of Ba6Mg11F34 and the solid solutions Ba6Mg11−xM(II)xF34 (M(II) = Mn, Fe) and luminescence of Ba6Mg11F34: Eu2+

Ba6Mg11F34, a new compound of the pseudobinary BaF2–MgF2 system, has been synthesized by solid state techniques from stoichiometric amounts of BaF2 and MgF2 and its crystal structure determined by single crystal X-ray diffraction (space group P1̄, a=7.5084(6), b=9.9192(8), c=10.0354(8) Å, α=81.563(2), β=72.402(2), γ=71.198(1)°, 3899 structure factors, 233 parameters, R(F2>2σ(F2))=0.018, wR(F2 all) = 0.046). It is isotypic with the copper(II) analogue, Ba6Cu11F34. The main features of the structure are a network of [MgF6] octahedra and three different [BaFx] polyhedra with x=12, 11+1 and 13. Ba6Mg11−xFexF34 and Ba6Mg11−xMnxF34 solid solutions were prepared and their composition determined by single crystal structure analyses. The luminescence properties of Ba6Mg11F34 doped with Eu2+ were studied using fluorescence spectroscopy. The observed luminescence was pale blue with a maximum at 465 nm.