- Synthesis and structure of an infinite-chain form of ZrI2 (α)
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The synthesis of a second polymorph of ZrI2 has been achieved by a transport reaction between ZrI4 and zirconium metal under a 750 850°C gradient in a sealed tantalum tube. The black lath-like crystals produced in the 775°C region occur in space group P21 m with a = 6.821(2) A, b = 3.741(1) A, c = 14.937(3) A, β = 95.66(3)°, Z = 4. A total of 669 independent reflections with 2θ ≤ 50° and I > 3σ(I) were measured at room temperature on a four-circle automated diffractometer with monochromatized MoKα radiation and were corrected for absorption (μ = 190 cm-1). The structure was solved by direct methods and full-matrix least-squares refinement of all atoms with anisotropic thermal parameters to give final residuals R = 0.064 and Rw = 0.079. This phase is isoelectronic and isostructural with β-MoTe2, a distorted CdI2-type structure in which the zirconium atoms are displaced 0.440 A from the octahedral centers along a to form infinite zigzag metal chains (dZrZr = 3.182(3) A) parallel to b. The phase is a diamagnetic semiconductor at room temperature (Eg ~ 0.1 eV).
- Guthrie, Dennis H.,Corbett, John D.
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- New Double Salts with Boron-Centered Zirconium Clusters: Syntheses and Structures of Cs[ZrCl5]·Cs2[(Zr6B)X 15] (X = Cl or Cl+I), and Anion Distribution in the Mixed Halide Phase
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Two new members of a double salt containing halide supported zirconium octahedra were obtained from solid state reactions. Single-crystal X-ray data refinements established the isotypic compounds as Cs[ZrCl5] ·Cs2[(Zr6B)Cl15] (I) (R?c, Z = 6, a = 12.765(2), c = 34.652(6) A?, R1(F) = 0.0339, wR2(F2) = 0.0770) and the mixed halide Cs[ZrCl5]·Cs2[(Zr 6B)Cl14.57(2)I0.43] (II) (R3?c, Z = 6, a = 12.777(2), c = 34.668(7) A?, R1(F) = 0.0459, wR2(F2) = 0.1279), respectively. The structure contains a network of boron centered [(Zr 6B)Cli12] clusters interbridged three-dimensionally by 6/2 Xa-a atoms at all zirconium vertices (X = Cl, or Cl+1, respectively). Within voids of the cluster network [ZrCl 5]- anions and Cs+ cations are located, allowing for the description as a double salt. The [ZrCl5] - anion (D3h-symmetry) has been found so far only in this structure type. The space requirement of a variety of transition metal complexes is estimated and compared with the volume of the [ZrCl 5]- anion in order to see if other double salts are geometrically possible. Besides the unusual [ZrCl5]- ion the mixed chloride-iodide structure reveals another interesting feature. Contrary to many other structures an ordered chlorine atom substitution by iodine is observed on the cluster interconnecting site. The phase width for Cs[ZrCl5]·Cs2[(Zr6B)Cl 15-XIX] has been found to cover 0 ≤ x ≤ 1.
- Rohm, Henning W.,K?ckerling, Martin
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- KINETICS OF FORMATION OF SOLID IODIDES ON ZIRCONIUM.
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The reaction of zirconium with gaseous ZrI//4 was studied in the temperature range 300-500 degree C. Specimens of zirconium were heated in sealed glass tubes with solid ZrI//4 which was kept at a lower temperature to maintain a fixed ZrI//4 pressure. The solid zirconium iodides that formed on the zirconium surface were examined by scanning electron microscopy. Initially, isolated clusters of ZrI crystals formed which subsequently coalesced into a layer of ZrI. A layer of diiodide formed on top of the layer of monoiodide in later stages. The amount of iodide on the surface was determined by chemical analysis.
- Cubicciotti,Scott
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- THERMODYNAMICS OF VAPORIZATION OF ZrI4 IN THE UNIVARIANT REGION: ZIRCONIUM MONOIODIDE/ZIRCONIUM.
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The pressures of gaseous ZrI//4 over solid zirconium iodides in the composition range ZrI to Zr were measured by a torsion-effusion method. A univariant region was observed between solids of composition ZrI//1//. //0//5 and Zr. The results extend literature information on the thermodynamics of vaporization in the ZrI//4/Zr region of the Zr-I system.
- Cubicciotti,Lau
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- Arene Derivatives of Zirconium(II) and Hafnium(II)
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The anhydrous tetrahalides MX4 (M = Zr or Hf, X = Br or I) were prepared by treating M(BH4)4 with dry HX in n-heptane as solvent, followed by sublimation under reduced pressure.The reaction of ZrCl4 with Al-AlCl3-aromatic hydrocarbon systems led to soluti
- Calderazzo, Fausto,Pallavicini, Piersandro,Pampaloni, Guido
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p. 1813 - 1818
(2007/10/02)
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