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Neven Strukan Marina Cindri Boris Kamenar 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):639-641
The crystal and molecular structure of dipotassium di‐μ‐oxo‐bis[aqua(oxalato‐O1,O2)oxomolybdenum(III)] trihydrate, K2[Mo2O4(C2O4)2(H2O)2]·3H2O, has been determined from X‐ray diffraction data. In the dimeric anion, which has approximate twofold symmetry, each Mo atom is in a distorted octahedral coordination, being bonded to one terminal oxo‐O atom, two bridging O atoms, two O atoms from the oxalato ligand and one from the water molecule. Bond lengths trans to the multiple‐bonded terminal oxo ligand are larger than those in the cis position, confirming the trans influence as a generally valid rule. 相似文献
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The 1/2V2O5-H2C2O4/H3PO4/NH4OH system was investigated using hydrothermal techniques. Four new phases, (NH4)VOPO(4).1.5H2O (1), (NH4)0.5VOPO(4).1.5H2O (2), (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O (3), and (NH4)2[VO(HPO4)]2(C2O4).H2O (4), have been prepared and structurally characterized. Compounds 1 and 2 have layered structures closely related to VOPO(4).2H2O and A0.5VOPO4.yH2O (A = mono- or divalent metals), whereas 3 has a 3D open-framework structure. Compound 4 has a layered structure and contains both oxalate and phosphate anions coordinated to vanadium cations. Crystal data: (NH4)VOPO(4).1.5H2O, tetragonal (I), space group I4/mmm (No. 139), a = 6.3160(5) A, c = 13.540(2) A, Z = 4; (NH4)0.5VOPO(4).1.5H2O, monoclinic, space group P2(1)/m (No. 11), a = 6.9669(6) A, b = 17.663(2) A, c = 8.9304(8) A, beta = 105.347(1) degrees, Z = 8; (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O, triclinic, space group P1 (No. 2), a = 10.2523(9) A, b = 12.263(1) A, c = 12.362(1) A, alpha = 69.041(2) degrees, beta = 65.653(2) degrees, gamma = 87.789(2) degrees, Z = 2; (NH4)2[VO(HPO4)]2(C2O4).5H2O, monoclinic (C), space group C2/m (No. 12), a = 17.735(2) A, b = 6.4180(6) A, c = 22.839(2) A, beta = 102.017(2) degrees, Z = 6. 相似文献
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I. V. Medrish E. V. Peresypkina A. V. Virovets L. B. Serezhkina 《Russian Journal of Coordination Chemistry》2006,32(12):910-914
The single crystals of (C2H7N4O)2[UO2(C2O4)2(H2O)] were studied by X-ray diffraction. The crystals are monoclinic, space group Pn, Z = 2, unit cell parameters: a = 9.4123(2) Å, b = 8.4591(2) Å, c = 11.8740(3) Å, β = 105.500(10)°, V = 911.02(4) Å3. The main structural units of the crystals of I are islet complex groups [UO2(C2O4)2(H2O)]2? corresponding to the crystal chemical group AB 2 01 M1 (A = UO UO 2 2+ , B01 = C2O 4 2? , M = H2O) of uranyl complexes. Uranium-containing mononuclear complexes are connected into a three-dimensional framework through the electrostatic interactions and hydrogen bonding system involving carbamyolguanidinium ions. 相似文献
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Clark RJ Firth S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(8):1731-1746
The Raman and infrared spectra of solid K2(12)C2O4 x H2O are reported together with, for the first time, the corresponding Raman and infrared spectra of solid K2(13)C2O4 x H2O. Raman spectra of aqueous solutions of both isotopomers are also reported. In the solid state the oxalate anion is planar with D2h symmetry in this salt, whereas in aqueous solution the Raman spectra of the anion are best interpreted on the basis of D2d symmetry. The Raman spectra of solid (NH4)2(12)C2O4 x H2O and (NH4)2(13)C2O4 x H2O, in which the oxalate anion is twisted from planarity by 28 degrees about the CC bond, have also been recorded. Several reassignments have been made. The harmonic force field for the oxalate anion in the D2h, D2 and D2d geometries has been determined in part, and approximate values of key valence force constants determined. All the observed band wavenumbers and 12C/13C isotopic shifts are well reproduced by the force fields. The potential energy distribution of the totally symmetric normal modes of planar oxalate indicates that each mode consists of extensively mixed symmetry corrdinates and that the labels previously used for the bands seen here at 475 and 879 cm(-1) would better be described as v(CC) and deltaS(CO2), respectively, putting them in the same wavenumber order as v(NN) and deltaS(NO2) for the isoelectronic and isostructural molecule N2O4. The stretching force constants of N2O4 and planar C2O4(2-) are established to be in the order f(NN) < f(CC) and f(NO) > f(CO), consistent with the known relative bond lengths. 相似文献
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I. L. Botto E. J. Baran A. C. Garcia 《Journal of Thermal Analysis and Calorimetry》1986,31(6):1301-1308
The IR and Raman spectra and the thermal behaviour of the isomorphous compounds (NH4)3Ga(C2O4)3·3H2O and (NH4)3Al(C2O4)3·3H2O were investigated. Detailed stoichiometries, sustained by TG, DTA and IR spectroscopic analyses, were found in both cases. Different results, associated with the different polarizing powers of the metal cations, were obtained. The first evidence was found of the formation of basic gallium carbonates. 相似文献
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The reaction of ZrCl4 with [gamma-SiW10O36]8- in a potassium acetate buffer results in two different products depending on the reactant ratios. The trimeric species [Zr6O2(OH)4(H2O)3(beta-SiW10O37)3]14- (1) consists of three beta23-SiW10O37 units linked by an unprecedented Zr6O2(OH)4(H2O)3 cluster with C1 point group symmetry. The dimeric species [Zr4O2(OH)2(H2O)4(beta-SiW10O37)2]10- (2) consists of beta22- and beta12-SiW10O37 units sandwiching a Zr4O2(OH)2(H2O)4 cluster, which also has C1 symmetry. Polyanion 1 contains more zirconium centers than any other polyoxometalate known to date. 相似文献
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Masato Hashimoto Michiru Kubata Atsushi Yagasaki 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1411-1412
The title compound, triammonium cis‐diaqua‐cis‐dioxo‐trans‐disulfatovanadate 1.5‐hydrate, was obtained by oxidizing VIV to VV in a 2 M sulfuric acid solution of vanadyl sulfate and adding ammonium sulfate. Here, the V atom is sandwiched by two sulfate groups by corner‐sharing to form a discrete [VO2(SO4)2(OH2)2]3? anion. The water molecules occupy cis positions in the equatorial plane of the vanadium octahedron. 相似文献
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Formation of well-aligned and single-crystalline ZnGa(2)O(4) nanowires on sapphire (0001) substrates has been achieved via annealing of the Ga(2)O(3)/ZnO core-shell nanowires. Ga(2)O(3)/ZnO core-shell nanowires were prepared using a two-step method. The thickness of the original ZnO shell and the thermal budget of the annealing process play crucial roles for preparing single-crystalline ZnGa(2)O(4) nanowires. Structural analyses of the annealed nanowires reveal the existence of an epitaxial relationship between ZnGa(2)O(4) and Ga(2)O(3) phases during the solid-state reaction. A strong CL emission band centered at 360 nm and a small tail at 680 nm are obtained at room temperature from the single-crystalline ZnGa(2)O(4) nanowires. 相似文献
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Uwe Kolitsch 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):m129-m133
Rubidium chromium(III) dioxalate dihydrate [diaquabis(μ‐oxalato)chromium(III)rubidium(I)], [RbCr(C2O4)2(H2O)2], (I), and dicaesium magnesium dioxalate tetrahydrate [tetraaquabis(μ‐oxalato)magnesium(II)dicaesium(I)], [Cs2Mg(C2O4)2(H2O)4], (II), have layered structures which are new among double‐metal oxalates. In (I), the Rb and Cr atoms lie on sites with imposed 2/m symmetry and the unique water molecule lies on a mirror plane; in (II), the Mg atom lies on a twofold axis. The two non‐equivalent Cr and Mg atoms both show octahedral coordination, with a mean Cr—O distance of 1.966 Å and a mean Mg—O distance of 2.066 Å. Dirubidium copper(II) dioxalate dihydrate [diaquabis(μ‐oxalato)copper(II)dirubidium(I)], [Rb2Cu(C2O4)2(H2O)2], (III), is also layered and is isotypic with the previously described K2‐ and (NH4)2CuII(C2O4)2·2H2O compounds. The two non‐equivalent Cu atoms lie on inversion centres and are both (4+2)‐coordinated. Hydrogen bonds are medium‐strong to weak in the three compounds. The oxalate groups are slightly non‐planar only in the Cs–Mg compound, (II), and are more distinctly non‐planar in the K–Cu compound, (III). 相似文献
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The non-centrosymmetric microporous fluorinated iron phosphate, (H3O)2[Fe4(H2O)2F4(PO4)2(HPO4)2](H2O), is endowed with properties. In fact, the thermogravimetric analysis study shows a mass loss evolution as a temperature function. The optical study was also examined by UV–vis absorption. The magnetic results reveal the appearance of a ferromagnetic behavior at low temperature (Tc = 11.64 K). 相似文献