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1.
IrIn7GeO8 = [IrIn6](GeO4)(InO4) and Compounds of the Solid Solution Series [IrIn6](Ge1+xIn1?4x/3O8) (0 ≤ x ≤ 0.75): First Oxides containing [IrIn6] Octahedra The low valent indiumoxides IrIn7GeO8 = [IrIn6](GeO4)(InO4) and [IrIn6](Ge1+xIn1?4x/3O8) (0 x ≤ 0.75) are formed by heating intimate mixtures of Ir, In, In2O3 and GeO2 in corundum crucibles under an atmosphere of argon (1420 K, 70 h). The compounds are black and semiconducting. X‐ray powder diffraction patterns can be indexed on the basis of a face centered cubic unit cell with lattice parameters ranging from a = 1012.3(1) pm (x = 0) to a = 1007.3(1) pm (x = 0.75). Characteristic building units in [IrIn6](Ge1+xIn1?4x/3O8) are isolated [IrIn6]9+ octahedra with short Ir‐In distances of 253.5 pm, which are linked via [GeO4]4? and [InO4]5? tetrahedra to a three dimensional framework. Starting from IrIn7GeO8 = [IrIn6](GeO4)(InO4), the isoelectronic substitution of 4 In3+ ions by 3 Ge4+ ions and one Ge‐vacancy leads to the formation of a solid solution series [IrIn6](GeO4)1+x(O4)x/3(InO4)1?4x/3, which shows a slight decrease in the cubic lattice parameter with increasing x. According to Rietveld refinements the structure of [IrIn6](GeO4)(InO4) exhibits a statistical distribution of the tetrahedrally coordinated Ge and In atoms ( , R(prof.) = 4.4 %, R(int.) = 2.5 %). The crystal and electronic structures of [IrIn6](GeO4)(InO4) are discussed on the basis of first principles electronic structure calculations.  相似文献   

2.
The use of polymers containing metal salts as ceramic high‐temperature superconductor (HTSC) precursors may provide a relatively simple and rapid method for producing materials that can take advantage of advanced polymer processing and then be pyrolyzed to HTSCs. The mechanisms of thermal degradation in these precursors, which have not been characterized, can be used to optimize the pyrolysis conditions for HTSC production. This article describes the degradation of a precursor based on poly(acrylic acid) (PAAc) containing yttrium, barium, and copper nitrates in the proportions needed for the formation of the HTSC YBa2Cu3O7?x (YBCO). This article also describes the effects of the pyrolysis process on the resulting materials. The degradation of the precursor is a complex, multistage process. The presence of the metal ions and HNO3 reduces the thermal stability of PAAc and increases the degradation rate. The results indicate that the initial stages of the pyrolysis should be conducted in argon or nitrogen to inhibit BaCO3 formation and that the final stages should be conducted in air/oxygen to enhance oxidation. Optimization of the pyrolysis conditions produces a YBCO film with minimal contamination. © 2005 Wiley Periodicals, Inc. J PolymSci Part B: Polym Phys 43: 1168–1176, 2005  相似文献   

3.
Synthesis and Crystal Structures of (Ph4P)4[Bi8I28], (nBu4N)[Bi2I7], and (Et3PhN)2[Bi3I11] – Bismuth Iodo Complexes with Isolated and Polymeric Anions Solutions of BiI3 in methanol react with NaI and (nBu4N)(PF6) or (Et3NPh)(PF6) to form anionic bismuth iodo complexes (nBu4N)[Bi2I7] 1 and (Et3PhN)2[Bi3I11] 2 . In 1 Bi4I16 units, and in 2 Bi6I24 units are linked by common I-atoms to onedimensional infinite chains. Reaction of BiI3 with (Ph4P)(PF6) in methanol yields (Ph4P)4[Bi8I28] 3 . The anions of 1–3 consist of edge-sharing BiI6 octahedra. (nBu4N)[Bi2I7] 1 : Space group I2/m (No. 13), a = 1 082.3(5), b = 2 597.1(13), c = 1 206.1(6) pm, β = 93.17(2)°, V = 3 385(3) · 106 pm3; (Et3PhN)2[Bi3I11] 2 : Space group P1 (No. 2), a = 1 283.5(6), b = 1 345.9(7), c = 1 546.3(8) pm, α = 83.87(2), β = 74.24(2), γ = 68.26(2)°, V = 2 388(2) · 106 pm3; (Ph4P)4[Bi8I28] 3 : Space group P1 (No. 2), a = 1 329.3(4), b = 1 337.0(4), c = 2 193.1(5) pm, α = 104.20(2), β = 99.73(2), γ = 100.44(2)°, V = 3 622(2) · 106 pm3.  相似文献   

4.
CF3S(O)F, (CF3)2SO, CF3SF3, (CF3)2SF2, and SF4 react in different manner with XeF+MF6? (M?As, Sb). An oxidative fluorination is observed by CF3S(O)F forming the persulfonium salt CF3S(O)F2+SbF6?, whereas by (CF3)2SO a simple addition product containing xenon can be isolated in form of the sulfonium salt (CF3)2SOXeF+SbF6?. On the contrary, the Lewis-acidic character of the XeF+-cation predominates against (CF3)nSF4?n (n = 0 ? 2) leading to the corresponding fluorosulfonium salts (CF3)nSF3?n +MF6? (M?As, Sb) and XeF2.  相似文献   

5.
Preparation of (C6F5)2SF+MF6? (M ? As, Sb) and Crystal Structure of (C6F5)2SF+SbF6? XeF+MF6? (M ? As, Sb) reacts with (C6F5)2S in HF to form (C6F5)2SF+MF6?. The deeply violet sulfonium salts can be kept without decomposition up to 24 h at room temperature. The hexafluoroantimonate salt crystallizes in the monoclinic space group P21/n with a = 1056.4(7) pm, b = 1446.3(10) pm, c = 1102.9(8) pm, β = 91.29(6)° und Z = 4. The SF-bond distance with 158.4(3) pm is of unusual length. Cations and anions are connected via interionic fluorine contacts to an infinite chain, in which cations and anions form to ABAB sequence along the chain.  相似文献   

6.
The novel compounds Sr13NbAs11 and Eu13NbAs11 have been synthesized from SrAs, Eu5As4, Sr, Nb and As in niobium ampoules at 1173–1273 K. The tetragonal tI 200 phases are defect variants of the Ca14AlSb11 structure (space group I41/acd (no. 142); Sr13□NbAs11: a = 1649.8(2) and c = 2214.1(3); Eu13□NbAs11: a = 1632.9(8) and c = 2197.3(8) pm; Z = 8). The structures are built from the cations Sr2+, and Eu2+, respectively, and from the anions [NbAs4]7?, As3?, and the linear polyanion [As3]7?. This polyanion (isosteric to I3?) is asymmetric with d(As? As) = 273.0 and 346.0 pm (Sr) and 274.7 and 335.6 pm (Eu), respectively. The bond lengths in the tetrahedral anions are d(Nb? As) = 250.8 and 251.1 pm. The complete structural arrangement is related to that of Cu2O by forming two interpenetrating networks. The oxygen atoms are substituted by niobium centered As4 tetrahedra, and the Cu atoms are substituted by As6 octahedra (centered by Sr, Eu). The central As atoms of the polyanions connect the nets. Both As networks are enveloped by the remaining cations forming cubes, tetragonal antiprisms and capped trigonal prisms.  相似文献   

7.
High Resolution Electron Microscopy Investigations of La2CeTaO6Cl3 and its Thermal Decomposition Product La2Ce Ce TaO6Cl3?x The thermal decomposition of the hexagonal La2CeTaO6Cl3 led to a mixed-valent product La2CeCe TaO6Cl3?x with a complicated monoclinic structure. The detailed inspection shows two subunits A and B, which form the monoclinic unit cell by a ABAB sequence. The subunit A is almost identical to the hexagonal cell of the starting material while subunit B has additional Ln- and Cl-positions. For this reason, the main structure features of the monoclinic compound and the starting material are related, which is clearly seen in the electron microscopy investigations. As might be expected from the relationship between the subunits A and B one can observe defects in the monoclinic compound arising from the various possibilities of combining these building elements. We also found structure defects in the hexagonal starting material, which are caused by the presence of the subunit B.  相似文献   

8.
Preparation and Crystal Structures of Dipyridiniomethane Monohalogenohydro-closo-Dodecaborates(2?), [(C5H5N)2CH2][B12H11X]; X = Cl, Br, I [B12H12]2? reacts with dihalogenomethanes CH2X2 in presence of trifluoro acetic acid, yielding the monohalogenododecaborates [B12H11X]2? (X = Cl, Br, I), which are separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from the starting compound and higher halogenated products. The X-ray structure determinations of [(C5H5N)2CH2][B12H11Cl] · 2(CH3)2SO (orthorhombic, space group Pnma, a = 17.351(6), b = 16.034(5), c = 9.659(2) Å, Z = 4) and of the isotypic bromo and iodo compounds [(C5H5N)2CH2][B12H11X] (monoclinic, space group P21/n, Z = 4; for X = Br: a = 7.339(2), b = 15.275(3), c = 16.761(4) Å, β = 96.80(2)°; for X = I: a = 7.4436(8), b = 15.3510(8), c = 16.9213(16) Å, ß = 97.326(7)°) exhibit crystal lattices build up by columns of substituted boron clusters and angular dications [(C5H5N)2CH2]2+ orientated along the shortest axis which are assembled to alternating layers.  相似文献   

9.
Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVI [1] Reactions of [g2-{P–PtBu2}Pt(PPh3)2] and [g2-{P–PtBu2}Pt(dppe)] with Metal Carbonyls. Formation of [g2-{(CO)5M · PPtBu2}Pt(PPh3)2] (M = Cr, W) and [g2-{(CO)5Cr · PPtBu2}Pt(dppe)] [η2-{P–PtBu2}Pt(PPh3)2] 4 reacts with M(CO)5 · THF (M = Cr, W) by adding the M(CO)5 group to the phosphinophosphinidene ligand yielding [η2-{(CO)5Cr · PPtBu2}Pt(PPh3)2] 1 , or [η2-{(CO)5W · PPtBu2}Pt(PPh3)2] 2 , respectively. Similarly, [η2-{P–PtBu2}Pt(dppe)] 5 yields [η2-{(CO)5Cr · PPtBu2}Pt(dppe)] 3 . Compounds 1 , 2 and 3 are characterized by their 1H- and 31P-NMR spectra, for 2 and 3 also crystal structure determinations were performed. 2 crystallizes in the monoclinic space group P21/n (no. 14) with a = 1422.7(1) pm, b = 1509.3(1) pm, c = 2262.4(2) pm, β = 103.669(9)°. 3 crystallizes in the triclinic space group P1 (no. 2) with a = 1064.55(9) pm, b = 1149.9(1) pm, c = 1693.2(1) pm, α = 88.020(8)°, β = 72.524(7)°, γ = 85.850(8)°.  相似文献   

10.
Different from the case of the benzene dimer, the differences between the interaction energies are always less than 0.50 kcal/mol for face‐to‐face eclipsed, face‐to‐face staggered, and parallel‐displaced configurations of all investigated complexes C6H6···C6X6 (X = F, Cl, Br, and I). Hence, it is a great challenge for quantum chemists to accurately calculate the interaction energies for the three configurations of the complexes C6H6···C6X6. This work demonstrates that results obtained with the PBE0 density functional combined with the D3 dispersion correction (PBE0‐D3) and the basis set def2‐TZVPP are in excellent agreement with the estimates of the coupled‐cluster singles, doubles, and perturbative triples [CCSD(T)] complete basis set (CBS) limit. The other finding in this study is that, in comparison with the gold‐standard CCSD(T)/CBS benchmark, the spin‐component scaled (SCS) zeroth‐order symmetry‐adapted perturbation theory (SAPT0), when paired with the basis set aug‐cc‐pVDZ, performs also very well, and its performance is even better than that of the PBE0‐D3/def2‐TZVPP method or the conventional SAPT/aug‐cc‐pVQZ method. The findings of this study are very significant because both PBE0‐D3/def2‐TZVPP and SCS‐SAPT0/aug‐cc‐pVDZ can deal with the systems with more than 200 atoms.  相似文献   

11.
The intermolecular π‐hole···π‐electrons interactions between F2ZO (Z = C, Si, Ge) molecules and unsaturated hydrocarbons including acetylene, ethylene, 1,3‐butadiene and benzene were constructed to reveal the differences of tetrel bonds forming by carbon and heavier tetrel atoms. The ab initio computation in association with topological analysis of electron density, natural bond orbital, and energy decomposition analysis demonstrate that the strength of Si···π and Ge···π tetrel bonds is much stronger than that of C···π tetrel bonds. The Si···π and Ge···π tetrel bonds exhibit covalent or partially covalent interaction nature, while the weak C···π tetrel bonds display the hallmarks of noncovalent interaction, the electrostatic interaction is the primary influencing factor. The Si···π and Ge···π interactions are determined by both the σ‐ and π‐electron densities, while the C···π interactions are dominated mainly by the π‐electron densities. The π‐hole···π‐electrons tetrel bonds are dominated by electrostatic interaction, and polarization has a comparable contribution in the Si···π and Ge···π tetrel bonds.  相似文献   

12.
To provide theoretical insight into the structures and properties of Sc3N@C80, which has been isolated in high yield and purity as a new stable endohedral metallofullerene, density functional calculations are carried out for the Sc3?nLanN@C80 (n=0–3) series. Because of electron transfer from Sc3N to C80, the electronic structure of Sc3N@C80 is formally described as (Sc3N)6+C$_{80}^{6-}$. The encapsulated Sc3N cluster takes a planar structure with long Sc–Sc distances and is highly stabilized inside the Ih cage of C80, which rotates rapidly. As the number of La atoms increases, the Sc3?nLanN cluster is forced to maintain a pyramidal structure in Sc3?nLanN@C80. In addition, the C80 cage takes an open‐shell electronic structure due to an increase in the number of electrons transferring from Sc3?nLanN. These make the endohedral structure less stable and more reactive. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1353–1358, 2001  相似文献   

13.
Bis(disulfide)bridged Nb(+4) cluster halide complexes [Nb2S4X8]4– (X = Cl, Br) were prepared by acid hydrolysis of [Nb2S4(NCS)8]4– in concentrated aqueous HCl or HBr, solution from which they can be isolated as double salts Cs5[Nb2S4X8]X (X = Cl, 1 ; X = Br, 2 ). The crystal structures of 1 and 2 were determined. The isolation and X-ray structure of oxonium salt (H3O)5 [Nb2S4Cl8]Cl ( 3 ) is also reported. 1 – 3 contain new [Nb2S4X8]4– anions which can also be viewed as excised building blocks of polymeric solids NbS2X2. The extra halogen resides in the center of octahedron formed by six Cs+ or H3O+ ions. All the three salts are isostructural and crystallize in tetragonal space group Immm with the following parameters: a = 10.269(2), b = 16.343(2), c = 7.220(1) Å for 1 , a = 10.934(1), b = 16.613(2), c = 7.470(1) Å for 2 , a = 9.639(1), b = 16.031(1), c = 7.071(1) Å for 3 . The parameters of the Nb2S4 core are only slightly affected by the change from Cl to Br.  相似文献   

14.
Capability of [ReIII(tu-S)6]Cl3, where tu = thiourea, as a precursor to other ReIII complexes by ligand substitution in aqueous medium is studied. For the decomposition of [Re(tu-S)6]Cl3, experiments suggest pseudo first order kinetics and observed rate constants vary from 1.3 × 10–2 to 9.6 × 10–2 min–1 in the pH range 2.80–5.04. Experiments in presence of incoming ligand (ethylendiaminetetraacetic acid or diethylentriaminepentaacetic acid) show that ligand substitution is significantly slower than decomposition of the precursor, even when pH and temperature are modified. Similar results were obtained working with [ReIII(Metu-S)6]Cl3, where Metu = N-methylthiourea. Molecular structure of [ReIII(Metu-S)6](PF6)3 · H2O was determined by single crystal X-ray diffractometry. The coordination polyhedron around the Re ion is a distorted octahedron. The six methylthiourea ligands are bonded to the metal through the sulfur atoms [bond lengths range from 2.409(2) to 2.451(2) Å].  相似文献   

15.
19F NMR Spectroscopic Evidence and Calculation of the Statistical Formation of Mixed Cluster Anions [(Mo6I Cl )F ]2?, n = 0–7, and Preparation of (TBA)2[(Mo6I )F ] The octa-μ3-iodo-hexafluoro-hexamolybdate(2?)ion [(Mo6I)F]2? is prepared for the first time. The system of the 21 innersphere mixed clusters (Mo6ICl)4+, n = 0–7 is formed by exchange of innersphere bound Cli against outersphere bound Ia on tempering solid [(Mo6Cl)I] at 400°C. Prolonged tempering leads to increasing average n values of the mixture, which is converted into the tetrabutylammonium salt (TBA)2[(Mo6ICl)F]. Using increments of chemical shifts and integral peak intensities the 54 19F-nmr signals of the 21 species (compound n = 8 is absent) are assigned and confirmed by the 2 D-19F/19F-COSY spectrum. From the measured intensities the distribution of the different compounds is determined and proves significant deviation from statistical occupation, revealing the preference of isomers with iodine atoms occupying edges of the innersphere cube and discrimination of those sharing diagonals of the faces. Moreover all compounds with n = 3 and 4 are present overaverage in comparison to the others.  相似文献   

16.
Single crystals of [Cu(ATSC)]NH2SO3 ( 1 ) (ATSC –4‐allylthiosemicarbazide) were obtained by electrochemical synthesis using alternating current. Compound ( 1 ) crystallizes in P212121 sp. gr., a = 6.8284(2), b = 9.3054(3), c = 16.1576(11) Å, Z = 4. ATSC moiety acts as tetradentate ligand, chelating two symmetrically related copper atoms. The Cu atom possesses trigonal pyramidal coordination, formed by two sulphur atoms (one of them at the apical position), nitrogen atom and C=C bond. Sulfamate anion is associated via hydrogen bonds. By slow hydrolysis of 1 crystals of [Cu2(ATSC)2]SO4 ( 2 ) were obtained: P 1 sp. gr., a = 9.526(2), b = 12.687(2), c = 14.7340(10) Å, α = 95.119(10), β = 89.903(12), γ = 109.113(14)°, Z = 4. The asymmetric unit of 2 contains two formula units, which are related by pseudosymmetry via a glide plane a. One half of four ATSC molecules act as in 1 , the rest as tridentate ligands, which coordinate the two copper atoms in apical positions with sulfate anions. This Cu–S coordination was to date unknown. The structure of the ATSC ligands contributes to the unexpected competitiveness of C=bond in the coordination sphere of CuI inspite of strong donor atoms.  相似文献   

17.
Iron-57 Mössbauer spectroscopy confirms a high sensitivity of the three-dimensional magnetic ordering temperature (TNéel) for a series of new intergrowth phases to both oxygen stoichiometry and the partial substitution of iron by copper and aluminium in the Ruddlesden-Popper phase LaSr3Fe3010?δ. The chemical isomer shifts suggest that significant covalent electron delocalization exists in these phases. Spectra for the paramagnetic phases indicate two distinct iron coordination environments consistent with x-ray and neutron diffraction structure determinations. The Mössbauer spectra at 4.8 K exhibit the overlap of two magnetic hyperfine patterns corresponding to cooperative magnetic order at the iron sites with internal fields of 45 and 27 Tesla for nominal Fe3+ and Fe4+ sites respectively.  相似文献   

18.
Preparation and Spectroscopic Characterization of the Persulfonium Salts (CH3)(CF3)SF3+SbF6? and (CH3)(CF3)2SF2+SbF6? and Crystal Structure of CF3SF2+SbF6? [1] . The preparation of the persulfonium salts (CH3)(CF3)SF3+SbF6? and (CH3)(CF3)2SF2+SbF6? by methylation of the sulfuranes CF3SF3 and (CF3)2SF2 with CH3OSO+SbF6? in liquid SO2 is reported. The thermolabile compounds are characterized by IR, Raman, 1H, 13C, and 19F NMR spectroscopy. CF3SF2+SbF6? crystallizes in the space group C2/c with a=16.889(8) Å, b=7.261(4) Å, c=13.416(7) Å, β=91.08° with 8 formula units per unit cell at 167 K. Cations and anions are connected via short SF contacts forming a Ψ-octahedral surrounding of the central S atom which is in close analogy to the already known CF3SF2+AsF6?.  相似文献   

19.
The title compound [Cu2(phen)2(C9H14O4)2] · 6 H2O was prepared by the reaction of CuCl2 · 2 H2O, 1,10‐phenanthroline (phen), azelaic acid and Na2CO3 in a CH3OH/H2O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR2 = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu2(phen)2(C9H14O4)2] complexes and hydrogen bonded H2O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.  相似文献   

20.
Crystal Structure of Tetraphenylphosphonium Monothiocyanatohydro-closo-Decaborate, [P(C6H5)4]2[2-(SCN)B10H9] · CH3CN The X-ray structure determination of [P(C6H5)4]2[2-(SCN)B10H9] · CH3CN (monoclinic, space group P21/n, a = 10.6040(10), b = 13.8880(9), c = 33.888(3) Å, β = 94.095(8)°, Z = 4) reveals the S coordination of the SCN substituent with a B? S distance of 1.913(6) Å and a B? S? C angle of 105.3(3)°. The SCN group is nearly linear (178.2(7)°).  相似文献   

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