BA3NB2O2F12 . 2H2O - SYNTHESIS AND CRYSTAL-STRUCTURE

Single crystals of Ba3Nb2O2F12 · 2H2O were grown by hydrothermal synthesis in HF aqueous solutions. The structure is established from single crystal X-ray diffraction data: S.G. Cmc21, Z = 4, a = 22.633(3) Å, b = 7.804(1) Å, and c = 7.748(1) Å (R = 0.0310, Rw = 0.0331 for 2619 independent reflections and 99 parameters). The tridimensional network is built up from NbOF6 pentagonal bipyramids connected by Ba2+ ions (in 9- and 11-fold coordination). The location of anions and water molecules is discussed from bond valence calculations. © 1993 Academic Press, Inc.