Björn Blaschkowski, Harald Balzer, H. Keller
Oct 1, 2008
Citations
0
Influential Citations
8
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Journal
Zeitschrift für anorganische und allgemeine Chemie
Abstract
BaN3Cl: Synthesis, Crystal Structure, Vibrational Spectra and Thermal Decomposition of Barium Azide Chloride BaN3Cl was yielded as colourless, lath-shaped and oftenly intergrown single crystals from concentrated aqueous solutions of equimolar quantities of BaCl2 and NaN3. This first example of a ternary metal(II) azide chloride crystallizes monoclinically in space group P 21/m (no. 11) with the lattice constants a = 557.46(5) pm, b = 452.07(4) pm, c = 780.81(7) pm and β = 101.835(6)° (Z = 2). Its crystal structure contains Ba2+ cations in a ninefold monocapped tetragonal antiprismatic environment of five triatomic azide dumbbells (N3−) together with four chloride anions. The Cl− anions themselves are surrounded by four Ba2+ cations tetrahedrally (d(Cl–Ba) = 311–316 pm), whereas N3− shows a fivefold distorted pyramidal Ba2+ coordination (d(N–Ba) = 295–297 pm). The participating ions are stacked in layers along the c-axis forming cationic sheets of which every rectangular face of four Ba2+ cations is capped with one N3− dumbbell. This arrangement of the involved ions corresponds to a monoclinically distorted variation of the matlockite-type structure of PbFCl and is therefore viewed as homeotypic. The azide dumbbell in barium azide chloride is strictly linear (∢(N–N–N) = 179.9(6)° and exhibits N–N bond lengths of 117 – 118 pm. The infrared and Raman spectra show vibration frequencies typical for a slightly asymmetric N3− unit (i. e. νas = 2070 cm−1, νs = 1352 cm−1 and δ = 644/634 cm−1). Thermal analyses revealed BaN3Cl to be stable up to 230 °C, before it decomposes to an amorphous solid under evolution of elemental nitrogen (N2).