13569-70-5Relevant articles and documents
Crystal structures of Ni(AlCl4)2, Ni(GaCl 4)2 and Na[Ni(AlCl4)3]
Ke?ler, Ulrich,Müller, Rainhard
, p. 1052 - 1058 (2007)
The crystal structures of Ni(AlCl4)2, Ni(GaCl 4)2 and Na[Ni(AlCl4)3] were determined by single crystal X-ray structure analysis. Ni(AlCl4) 2 and Ni(GaCl4)2 are isotypic and crystallize in the Co(AlCl4)2 structure type (I2/c, a = 1276.40(9)/1268.48(7), b = 771.41(5)/757,74(3), c = 1145.47(8)/1154.34(7) pm, β = 92.067(3)/91.778(4)°, Z = 4), The structure contains chains of NiCl6 octahedra and AlCl4/GaCl4 tetrahedra linked by corners and edges. Na[Ni(AlCl4)3] represents a new structure type (P21/c, a = 1356.34(6), b = 1200.82(6), c = 1213.31(6) pm, β = 105.647(6)°, Z = 4). Its characteristic feature is the chiral [Ni(AlCl4)3]- anion which is found here for the first time. The tetrachloroaluminate ions serve as bidentate ligands leading to an octahedral coordination of the nickel atom.
The preparation and properties of some pentachloroalkoxo complexes of niobium(IV)
Wentworth,Brubaker Jr.
, p. 551 - 554 (1963)
A number of complexes of the type (BH)2Nb(OR)Cl5 have been prepared by electrolytic reduction of NbCl5 in HCl-saturated alcohols, followed by the addition of alcoholic solutions of BH+ ions (B is an amine such as CH3NH2, pyridine, quinoline, etc.). All compounds show normal, spin-only paramagnetism for the d1 ion. Spectra of aromatic -inium salts are complicated and suggest that there is an interaction with the Nb(OR)Cl5- ion. The interaction seems to result in weakening of the aromatic C-H and the alkoxo C-O bonds and a distortion of the complex ion to greater tetragonality.
Niobium tetrahalide complexes with neutral diphosphine ligands
Benjamin, Sophie L.,Chang, Yao-Pang,Hector, Andrew L.,Jura, Marek,Levason, William,Reid, Gillian,Stenning, Gavin
, p. 8192 - 8200 (2016/06/01)
The reactions of NbCl4 with diphosphine ligands o-C6H4(PMe2)2, Me2PCH2CH2PMe2 or Et2PCH2CH2PEt2 in a 1 : 2 molar ratio in MeCN solution produced eight-coordinate [NbCl4(diphosphine)2]. [NbBr4(diphosphine)2] (diphosphine = o-C6H4(PMe2)2 or Me2PCH2CH2PMe2) were made similarly from NbBr4. X-ray crystal structures show that [NbCl4{o-C6H4(PMe2)2}2] has a dodecahedral geometry, but the complexes with dimethylene-backboned diphosphines are distorted square antiprisms. The Nb-P distances and 1) complexes were also characterised by microanalysis, magnetic measurements, IR and UV-visible spectroscopy. Using a 1 : 1 molar ratio of NbCl4 : diphosphine (diphosphine = Me2PCH2CH2PMe2, Et2PCH2CH2PEt2, Cy2PCH2CH2PCy2 and Ph2PCH2CH2CH2PPh2) afforded [NbCl4(diphosphine)], and [NbBr4(Me2PCH2CH2PMe2)] was obtained similarly. These 1 : 1 complexes are unstable in solution, preventing X-ray crystallographic study, but based upon their diamagnetism, IR, UV-visible and 31P{1H} NMR spectra, they are formulated as halide-bridged dimers [(diphosphine)X2Nb(μ-X)4NbX2(diphosphine)], with single Nb-Nb bonds and chelating diphosphines. The Nb(iv) complexes are prone to hydrolysis and oxidation in solution and the structures of the Nb(v) complexes [NbBr4(Me2PCH2CH2PMe2)2][NbOBr4(MeCN)] with a dodecahedral cation, and [{NbOCl3{Et2P(CH2)2PEt2}}2{μ-Et2P(CH2)2PEt2}] which contains seven-coordinate Nb(v) centres with a symmetrical diphosphine bridge, are reported. The structure of niobium tetrabromide, conveniently made from NbCl4 and BBr3, is a chain polymer with edge-linked NbBr6 octahedra and alternating long and short Nb-Nb distances, the latter ascribed to Nb-Nb bonds.
Solid state metathesis reactions in various applications
Gibson, Katharina,Stroebele, Markus,Blaschkowski, Bjoern,Glaser, Jochen,Weisser, Martina,Srinivasan, Radhakrishnan,Kolb, Heinz-Juergen,Meyer, Hans-Juergen
, p. 1863 - 1870 (2008/10/08)
Solid state metathesis reactions have been studied in fused silica tubes, by differential thermal analysis, and by X-ray powder diffraction. A selection of reactions between metal (La, Nb, and Ni) chlorides and lithium nitride or lithium acetylide were investigated to get more insight into reaction pathways and intermediate reaction stages that may be adopted on course of the formation of metal nitrides or carbides. Intermediate compounds are considered to be important because they can control the reactivity of a system. Such compounds were traced by changing the molar ratios of reaction partners away from the salt-balanced binary metal nitride or carbide target compositions. New preparative perspectives are discovered when metal chlorides were reacted with lithium nitridoborate or lithium cyanamide. Due to their reductive nature towards several d-block metal chlorides, (BN2)3- and (CN2)2- react to form metals or metal nitrides plus X-ray amorphous BN, and probably C3N4. With lanthanum chloride they can react to form nitridoborates and nitridocarbonates. The metathesis reaction between lithium cyanamide and cyanuric chloride (C3N 3Cl3) instead of metal chloride was studied for the synthesis of C3N4.
Thermal decomposition of niobium tetrachloride
Tsirelnikov,Bazhanova
, p. 63 - 68 (2008/10/09)
The thermal decomposition process of solid NbCl4 was studied by a tensimetric method using an ordinary and a two-zone membrane manometer. It was shown that the solid NbCl4 decomposed to the upper limit of a solid solution on the basis of a niobium trichloride crystal lattice and gaseous NbCl5. The homogeneity region of this solid solution is NbCl3.13-2.67 and it decomposes from an upper to a lower border with formation of the same gaseous product. After complete decomposition of the solid solution to its lower limit in the closed system the NbCl2.67 (cluster Nb3Cl8) form reacts with gaseous NbCl5 with formation of gaseous NbCl4. The thermodynamic characteristics of solid NbCl3.13 and NbCl2.67 and gaseous NbCl4 were calculated on the basis of experimental data:ΔfH°(NbCl3.13, s, 298.15 K) = -599 ± 10 kJ mol-1. ΔfH°(NbCl2.67, s, 298.15 K) = -536.4 ± 10.2 kJ mol-1 ΔfH°(NbCl4, g, 298.15 K) = -577.1 ± 8.5 kJ mol-1. ΔsH°(NbCl4, 298.15 K) = 128.4 ± 7.1 kJ mol-1.
Enthalpy of Formation of Niobium Tetrachloride
Bazhanova, L. M.,Efimov, M. E.,Medvedev, V. A.,Tsirel'nikov, V. I.
, p. 946 - 947 (2007/10/02)
The enthalpies of the reactions of NbCl5 (c), NbCl4 (c), NaNO3 (c), NaNO2 (sol., 48.6 H2O), HCl (sol., 17.1 H2O), and H2O (l) with a solution of 0.50 K2Cr2O7*0.454 HF*0.498 HCl*55.497 H2O (mole litre-1) have been determined in an LKB*8700 solution calorimeter with isothermal jacket at 298.15 K.From the results the standard enthalpy of formation ΔfH0 = -705.51 +/- 2.0 kJ mole-1 has been calculated.
Preparations, Properties, and Crystal and Molecular Structures of the Cyanomethane Adducts of Niobium(IV) Chloride and Di-μ-sulphido-bis
Benton, A. John,Drew, Michael G. B.,Hobson, Richard J.,Rice, David A.
, p. 1304 - 1309 (2007/10/02)
The cyanomethane adduct of NbCl4 analyses for NbCl4*3CH3CN (1).A crystal-structure determination of this species shows that it contains cis octahedral and a solvent CH3CN molecule.The unique bond lengths are Nb-N 2.220(13) Angstroem and Nb-Cl 2.328(2),2.343(6), and 2.349(4) Angstroem.The crystals of (1) are orthorhombic with unit-cell dimensions a=10.437(11), b=13.883(12), c=9.828(9) Angstroem, Z=4, and space group Pnma.A total of 729 reflections above background have been collected on a diffractometer and refined to R 0.051.When the cyanomethane adducts of NbX4 (X=Cl or Br) are treated with Sb2S3 in cyanomethane, adducts of NbX2S (X=Cl or Br) are formed.The products contain 2> in which there is a ring.The crystal structures of two compounds, (2) and (3), containing the 2> dimeric unit have been determined.In (2) there are two molecules of occluded CH3CN for each dimer while (3) has one.Both (2) and (3) are triclinic with space group P, with (2) having a=9.031(7), b=9.367(6), c=8.360(8) Angstroem, α=108.72(9), β=94.93(7), γ=105.70(8) degree, Z=1 and (3) having a=14.965(18), b=8.838(17), c=9.543(23) Angstroem, α=112.42(18), β=84.39(28), γ=103.65(21) degree, z=2.For (2), 1434, and for (3), 1530, independent reflections above background have been collected on a diffractometer and refined to R 0.056 and 0.050 respectively.The dimer configurations in (2) and (3) are identical.The niobium atoms are in a pseudo-octahedral enviroment consisting of two cis sulphur, two trans chlorine , and two cis nitrogen atoms .In addition, in each dimer there is a Nb-Nb single bond .
A study of the stereochemistry and magnetic and spectral properties of coordination compounds of the niobium(IV) and tantalum(IV) chlorides and bromides and of the complex anions NbCl62- and NbBr62-
Fowles,Tidmarsh,Walton
, p. 631 - 638 (2008/10/08)
Coordination complexes of the types NbX4·2L and MX4·B, where M = Nb or Ta; X = Cl or Br; L = acetonitrile, tetrahydrofuran, tetrahydropyran, or 1,4-dioxane; and B = 2,2′-bipyridyl or 1,10-phenanthroline have been prepared from the tetrahalides. The acetonitrile complexes NbX4·2CH3CN are useful starting materials for the preparation of the hexahalo salts [(C2H5)4N]2NbX6. The far-infrared spectra (500-200 cm-1) of the solid complexes NbX4·2L and MX4·B have been recorded and the metal-halogen stretching frequencies assigned. Interpretation of the latter indicates that these complexes have a cis-octahedral structure; for MX4·B, the chelating nature of the ligand molecules would in any case make this the most likely structure. The diffuse-reflectance spectra and temperature range magnetic properties of all of the niobium(IV) complexes are compared with related measurements on the model octahedral species NbX62-. These spectral measurements allow a fairly straightforward assignment of the halogen(π) → Nb(d) and d ? d transitions whereas the behavior of the magnetic properties of the complexes over the temperature range 300-80°K is not generally well understood.
The preparation and properties of niobium(IV) compounds. I. Some niobium(IV) halides and their pyridine adducts
McCarley, Robert E.,Torp, Bruce A.
, p. 540 - 546 (2008/10/08)
Reaction of NbBr5 and niobium metal in a sealed tube under a temperature gradient from 410 to 350° gave NbBr4 in good yields. However, an increase in the higher temperature from 410 to 450° was sufficient to eliminate NbBr4 as a product and cause deposition of a lower bromide. The halides NbCl4 and NbBr4 are isomorphous solids of orthorhombic structure and lattice constants a = 8.12, b = 8.88, c = 6.84 A?. and a = 8.60, b = 9.31, c = 7.19 A?., respectively; both solids are diamagnetic over the range -195 to 25°. Formation of the tetrahalodi-(pyridine)-niobium(IV) complexes resulted from the reactions of the pure tetrahalides (Cl, Br, I) with pyridine at room temperature; at elevated temperatures a second form of NbBr4(py)2 crystallized from pyridine. Evidence bearing on the structure of the pyridine adducts was obtained from conductance, spectral, and magnetic susceptibility measurements. The complexes are paramagnetic and exhibit moments much lower than the spin-only value for one magnetic electron; the spectra of solutions in pyridine show intense bands in the visible region which have been attributed to charge transfer transitions.
