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1.
A structural study of a nonstoichiometric niobium-zirconium oxyfluoride with the ReO3 type structure
Within the ZrNbOF quaternary system a nonstoichiometric compound of the ReO3 structure is formed with composition limits given by MX2.9MX3.14. Crystals at the lower end of this range with a composition of Nb0.55Zr0.45O1.1F1.8 (MX2.9) have been investigated by optical and electron microscopy and by powder and single crystal X-ray diffraction in order to determine the mode by which the nonstoichiometry has been accommodated in the structure. It was found that the material does not contain crystallographic shear planes or have a perovskite bronze type of structure but contains vacancies in the anion lattice. It seems likely that these defects are associated into clusters with a definite structure rather than being isolated from each other. 相似文献
2.
The crystal structure of KP8W40O136, the tenth member of the series KxP4O8(WO3)2m, has been resolved by three-dimensional single-crystal X-ray analysis. The space group is and the cell parameters are a = 19.589(3) Å, b = 7.5362(4) Å, c = 16.970(3) Å and β = 91.864(14)°. The framework is built up from ReO3-type slabs connected through pyrophosphate groups. The structure is compared to those of the other members of the series: although the ReO3-type slabs show a different type of tilting of the WO6 octahedra, the dispersion of WO distances is always higher for the octahedra linked to one or two P2O7 groups and decreases in proportion as W is farther from these groups. The perovskite cages of the slabs are described and compared to those encountered in the structures of WO3 and of the bronzes AxWO3. 相似文献
3.
Crystals of the trinuclear complex [(Me6C6)3Zr3Cl6][Al2Cl7]2 have been obtained from the reaction of ZrCl4, hexamethylbenzene, AlCl3, and Al in benzene. They are monoclinic, space group C2/2, with Z 4 and lattice parameters a 14.167(3), b 27.779(7), c 15.721(3) Å and β 94.27(4)°. The Zr atoms form a regular triangle. Each pair of Zr atoms is bridged by two Cl atoms. The fifth coordination site of each Zr atom is occupied by a h6-Me6C6 group. The cation is almost isostructural with the known trinuclear cation [(Me6C6)3Nb3Cl6]2+. Important distances are: ZrZr 3.35, ZrCl 2.56, and Zrcenter of C6 ring 2.17 Å. One of the two independent [Al2Cl7]? anions occurs in a staggered conformation and one occurs in an eclipsed conformation. 相似文献
4.
H. Vincent M. Ghedira J. Marcus J. Mercier C. Schlenker 《Journal of solid state chemistry》1983,47(1):113-121
Single crystals of the purple bronze K0.9Mo6O17 have been grown by a electrolytic reduction technique. Measurements of the electrical resistivity show that this compound is a quasi two-dimensional metal. A crystal structure determination is used to explain the strongly anisotropic resistivity. K0.9Mo6O17 is found to be trigonal with lattice parameters: a = 5.538 Å and c = 13.656 Å; Z = 1. The space group is . The K cations are surrounded by 12 oxygen anions which form icosahedral sites. One third of the Mo cations (Mo(1)) occupy tetrahedral sites, while the Mo(2) and Mo(3) cations have octahedral surroundings. The structure can be described as slabs of ReO3-type connected by KO12 icosahedra. Each slab is built up of 4 layers, parallel to the (001) plane, of Mo(2) and Mo(3) octahedra sharing corners. Two slabs are connected by K icosahedra which share 2 faces with the upper and lower neighboring Mo(3) octahedra. Each K icosahedron is edge linked to 3 upper and 3 lower Mo(1) tetrahedra. Each Mo(1) tetrahedron is itself corner linked to 3 Mo(3) octahedra of the neighboring layer. The deformations of the occupied polyhedra are a good illustration of the Pauling's third rule. There is no Mo(1)OMo(1) bonding, so that the MoOMo bonding, infinite in the a and b directions, is disrupted in the c direction. The Zachariasen's bond length-bond strength relation has been applied to the MoO bonds. The computed effective mean Mo valences are +6 for Mo(1) on tetrahedral sites and about 5.1 and 5.8, respectively, for Mo(2) and Mo(3) on octahedral sites. The 4d electrons of Mo atoms are so located in the two-dimensional infinite slabs of octahedra. The conduction band is expected to be an antibonding π1 band resulting from the hybridization of the Mo 4dt2g and oxygen pπ states. Thus, the structural properties should lead to a very anisotropic Fermi surface and thus, to a quasi two-dimensional electrical conductivity. 相似文献
5.
Na2Mn2S3 was prepared by reacting manganese powder with an excess of anhydrous sodium carbonate and elemental sulfur at 870 K. Extraction of the solidified melt with water and alcohol yielded well developed, bright red crystals. Na2Mn2S3 crystallizes with a new monoclinic structure type, space group , with a = 14.942(2)Å, b = 13.276(2)Å, c = 6.851(2)Å, and β = 116.50(1)°. The crystal structure was determined from single crystal diffractometer data and refined to a conventional R value of 0.026 for 1613 observed reflections. The atomic arrangement shows sulfur-manganese-sulfur slabs which are separated from each other by corrugated layers of sodium atoms. A prominent feature of the crystal structure is the formation of short, four-membered zigzag chains built up by MnS4 tetradedra sharing edges. These chains are further connected by the remaining apices to form an infinite sheet. Short MnMn distances (3.02 and 3.05 Å, respectively) are found within the four membered chains. Susceptibility measurements show antiferromagnetic interactions between the Mn atoms. 相似文献
6.
The crystal and molecular structure of hexaphenylditin selenide (C6H5)3SnSeSn(G6H5)3 was determined by X-ray diffraction data and was refined to R 0.055. The compound is monoclinic, space group P21, with a 9.950(4), b 18.650(7), c 18.066(6) Å, β 106.81(4)°, Z 4. The two molecules in the asymmetric unit differ slightly in their conformations, both having approximate C2 symmetry. Bond lengths and angles are: SnSe 2.526 (2.521(3) ? 2.538(3)) Å; SnC 2.138 (2.107(16)?2.168(19)) Å; SnSeSn 103.4(1)°, 105.2(1)°. There are only slight angular distortions at the SnSeC3 tetrahedra (SeSnC angles: 104.3(5)?114.8(4)°). The bond data indicate essentially single bonds around the Sn atoms. 相似文献
7.
The structure of Rh2(CH3CO2)4(DMF)2 {DMF = HCON(CH3)2} has been determined by single crystal X-ray methods. The compound crystallizes with eight formula units in a cell of dimensions: a = 29.438(7) Å, b = 7.978(2) Å, c = 20.279(5) Å, β = 113.20(4)°, V = 4377.5 Å3, space group C2/c. The structure has been refined by full-matrix least-squares method to a final R = 0.030 for the 4156 observed data. Two Rh(II) atoms are linked by four acetate groups forming a dimeric unit, where the RhRh distance is 2.383(1) Å. The coordination sphere about each Rh atom is completed by a DMF molecule; the average RhO(DMF) distance is 2.296(3) Å. 相似文献
8.
Kunio Miki Masahiro Yama Yasushi Kai Nobutami Kasai 《Journal of organometallic chemistry》1982,239(2):417-428
The molecular structure of a three-coordinate palladium(II)-styrene complex, [Pd(η5-C5H5)(PEt3)(styrene)]BF4 has been determined by means of X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c, with four formula units in a cell of dimensions: a 10.229(3), b 11.262(3), c 18.760(5) Å and β 103.77(2)°. The structure was solved by the heavy atom method, and refined by the least-squares procedure to R = 0.050 for 3635 observed reflections. The palladium atom is surrounded by the cyclopentadienyl group, the triethylphosphine ligand and the olefinic bond of styrene in the cationic complex. In the palladiumstyrene bonding, the olefinic bond is inclined by 77.3° to the coordination plane defined by the Pd and P atoms and the center of the cyclopentadienyl ring (PdC(1) 2.176(6), PdC(2) 2.234(5) and C(1)C(2) 1.369(8) Å). 相似文献
9.
M.N. Deschizeaux J.C. Joubert A. Vegas A. Collomb J. Chenavas M. Marezio 《Journal of solid state chemistry》1976,19(1):45-51
Single crystals of [ThCu3](Mn3+2Mn4+2]O12, a ferrimagnetic perovskite-like compound, have been synthesized by hydrothermal conditions at 600°C and 2 kbar. They have been found to be cubic, of space group Im3, with a = 7.359 Å, and isostructural with [NaMn3](Mn3+2Mn4+2)O12. The crystal structure has been refined by single-crystal X-ray diffraction data. The Th4+ cations are surrounded by slightly distorted icosahedra; the ThO distance is 2.556 Å. The Cu2+ cations are also surrounded by 12 oxygens, which are arranged as three mutually perpendicular rectangles of different size, the smallest and the largest of which are almost squares. The three sets of CuO distances are 1.973, 2.800, and 3.238 Å. The octahedral MnO distance is 1.950 Å. A test based on neutron diffraction powder data indicated that the square sites are occupied by only the Cu2+ cations. 相似文献
10.
Hydrocarbon solutions of Mo2(O—t-Bu)6 and PF3 (2 equiv) yield Mo4F4(O—t-Bu)8, I, and PF2(O—t-Bu). Compound I contains a bisphenoid of molybdenum atoms with two short MoMo distances, 2.26 Å, and four long MoMo distances, 3.75 Å, corresponding to localized MoMo triple bonding and non-bonding distances, respectively. The tetranuclear compound may be viewed as a dimer, [Mo2(μ2-F)2(O-t-Bu)4]2, and addition of PMe3 to hydrocarbon solutions of I yields Mo2F2(O—t-Bu)4(PMe3)2, II, which contains an unbridged MoMo triple bond of distance 2.27 Å. Each molybdenum atom is coordinated to two oxygen atoms, one fluorine atom and the phosphorus atom of the PMe3 ligand in a roughly square planar manner. The overall central Mo2O4F2P2 skeleton has C2 symmetry and NMR studies (1H, 19F and 31P) are consistent with the maintenance of this type of structure in solution. Infrared and electronic absorption spectral data are reported. These are the first compounds containing fluorine ligands attached to the (MoMo)6+ unit. 相似文献
11.
Kjell Waltersson 《Journal of solid state chemistry》1979,28(1):121-131
The crystal structure of has been determined and refined on the basis of three-dimensional X-ray diffractometer data (MoKα radiation). The structure is monoclinic, a = 7.710(2), b = 19.474(7), c = 7.216(2)Å, β = 116.75(1)°, V = 967.5Å3, Z =8, space group Cc (No. 9). The final R and Rw were 0.0295 and 0.0300, respectively, for 1356 independent reflections and 117 variables.The structure contains two crystallographically different VOF5 octahedra linked so as to form complex chains. Two non-equivalent octahedra share one FF edge, forming V2O2F8 doublets. Two F atoms, connected to different V atoms within the doublet, form an edge in the adjacent equivalent V2O2F8 unit thus continuing the chain. The VO distances are 1.583(7) and 1.595(7) Å. The VF distances are in the range 1.881-2.205 Å, mean value: 1.989 Å. The H2O group is a crystal water molecule. 相似文献
12.
Iwami Higashi Nobuhiro Shiotani M. Uda Tadashi Mizoguchi Hiroaki Katoh 《Journal of solid state chemistry》1981,36(2):225-233
The crystal structure of Mg51Zn20, a phase designated conventionally as “Mg7Zn3,” has been determined by the single-crystal X-ray diffraction method. It was solved by the examination of a Patterson synthesis, and refined by the ordinary Fourier and least-squares method; the R value obtained was 4.8% for 1167 observed reflections. The crystal is orthorhombic, space group Immm, with a = 14.083(3), b = 14.486(3), c = 14.025(3) Å, and Z = 2. There are 18 independent atomic sites, Zn1Zn6, Mg1Mg10, A, and B, and the last two sites are statistically occupied by Zn and Mg atoms with the occupancies; 0.46(2)Zn7 + 0.52(2)Mg11 and 0.24(2)Zn8 + 0.74(2)Mg12, for A and B, respectively. The structure of the crystal is described as an arrangement of icosahedral coordination polyhedra, to which all the atomic sites but Zn3 site belong. In this arrangement the Zn atoms other than the Zn3 and Zn8(B) center the icosahedral coordination polyhedra with coordination number 12. The Zn3, Zn8 atoms, and all the Mg atoms except Mg11(A) are located at the centers of various coordination polyhedra with the coordination numbers from 11 to 15. The distances between neighboring atoms are 2.71–3.07, 2.82–3.65, and 2.60–3.20 Å for ZnZn, MgMg, and ZnMg, respectively. 相似文献
13.
Paul S. Haradem Bertrand L. Chamberland Lewis Katz Alain Gleizes 《Journal of solid state chemistry》1977,21(3):217-223
A single crystal study of Ba3Pt2O7 shows that the structure tolerates a variable composition which can be written Ba3Pt2+xO7+2x. The crystal studied has a hexagonal cell of dimensions a = 10.108 ± 0.006 Å and c = 8.638 ± 0.009 Å, and a probable space group . The density determined by water displacement is 7.99 g/cm3; the theoretical density for Ba3Pt2O7 is 7.94 g/cm3. The structure was determined from the set of 401 observed independent reflections obtained from 5189 reflections measured by automated counter methods. Refinement on F was carried to a conventional R of 8.0%. The structure has barium-oxygen layers with an essentially four-layer stacking sequence of the double hexagonal (ABAB) type. Platinum is found mainly in face-sharing octahedra, but is also distributed over some sites in which the coordination is nearly square planar and other sites in which the coordination is trigonal prismatic with three PtO bond lengths of 2.00 Å and three long PtO distances of 2.65 Å. The platinum with planar coordination is 0.08 Å from the plane of the four oxygen atoms. 相似文献
14.
The ionic complex [(π-C5H5)2Zr(H2O)3]2+(CF3SO3?)2·THF, which corresponds to the 18-electron rule, is formed in the reaction of (π-C5H5)2Zr(CF3SO3)2(THF) with H2O in tetrahydrofuran. It crystallizes in the hexagonal space group P63 with Z = 6 and unit cell dimensions at ? 100°C of a 21.945(5) and c 8.711(3) Å. The geometry of the (π-C5H5)2Zr moiety (length of the vectors between Zr and the C5 ring centroids: 2.210 and 2.193 Å; angle between these vectors: 129.0°; angle between the C5 ring normals: 128.3°) agrees with that of neutral, four-coordinate (π-C5H5)2ZrX2 compounds. The three H2O ligands lie in the plane that bisects the angle between the C5 ring planes. The ZrO distances are 2.239(7), 2.195(7), and 2.261(7) Å. The CF3SO3? anions and the THF molecule of crystallization are packed around the complex cation in such a way that their oxygen atoms point towards the H2O ligands. The CF3 sides of the anion, on the other hand, are clustered together so as to produce hydrophobic domains in the crystal structure. 相似文献
15.
Jeffrey L. Petersen 《Journal of organometallic chemistry》1979,166(2):179-192
The hydrolysis of (η5-C5H5)2Zr(SC6H5)2 was shown previously by IR spectroscopy to produce an oxo-bridged complex. The molecular structure of this material has been determined by X-ray diffraction methods and consists of two (η2-C5H5)2Zr(SC6H5) units linked by an oxo bridge. The ZrOZr bond is nonlinear at 165.8(2)° with a Zr?Zr interatomic separation of 3.902(1)Å. The two independent SZrO bond angles of 98.7(1) and 103.3(1)° are consistent with a d° electronic structure for each zirconium atom. The relatively short ZrO distances of 1.968(3) and 1.964(3) Å support the presence of partial double-bond character arising from the donation of electron density from filled pπ-orbitals on the oxygen atom to unfilled d-orbitals on the electron deficient d0 metal atoms. This bonding feature requires based upon orbital symmetry arguments that the (ML)2O molecular core in [(η5-C5H5)2ML]2O complexes must be nonplanar with a dihedral angle between the two LMO planes less than 90°. For [(η5-C5H5)2Zr(SC6H5)]2O, dihedral angle of 61.7° was observed. The compound crystallizes in an orthorhombic space group, Pbca, with refined lattices parameters a 16.458(4), b 20.281(5), and c 17.016(4) Å. Full-matrix least-squares refinement of 2613 diffractometry data I > σ(I) led to a final discrepancy index R(F02) = 0.044. 相似文献
16.
The structure of primitive-cubic YbZrF7 has been determined using X-ray and neutron diffraction techniques. A unit cell (a = 4.07 Å, space group Pm3m) contains one formula unit of Yb0.5Zr0.5F3.5, with no ordering of cations, in materials prepared by rapid quenching from 1000°C. Metal and fluorine displacements from ideal sites are in accord with results previously obtained on Zr0.8Yb0.2F3.2O0.3. The separation between FF pairs bridging neighboring metal ions is similar to those observed in other complex zirconium fluorides. The metal displacements, metal-fluorine distances and fluorine-fluorine distances are discussed with respect to the formation and stability of disordered fluorine-excess ReO3-type phases. These materials are intermediate in character between phases such as monoclinic YbZrF7, with perfect order on both metal and nonmetal sublattices, and ZrF4-based glasses where there is disorder on the metal as well as on the fluorine sublattice. No ordering effects are observed on heating to near 200°C, but near 400°C there is a slow transformation to the monoclinic YbZrF7 structure. 相似文献
17.
M. Leblanc G. Ferey P. Chevallier Y. Calage R. De Pape 《Journal of solid state chemistry》1983,47(1):53-58
(H2O)0.33FeF3, grown by hydrothermal synthesis, crystallizes in the orthorhombic system with cell dimensions a = 7.423(3) Å, b = 12.730(4) Å, c = 7.526(3)Å, and space group Cmcm, Z = 12. The structure, derived from single crystal X-ray diffraction data (605 independent reflections) is refined to R = 0.019 (Rω = 0.021). The framework of the FeIIIF6 octahedra is related to that of hexagonal tungsten bronze (HTB) Rb0.29WO3. At 122°C, zeolithic water is evolved from hexagonal tunnels without any noticeable change of the fluorine skeleton. The related anhydrous compound represents a new form of iron trifluoride which is denoted HTBFeF3; at 525°C, it transforms into the cubic form of ReO3-type. (H2O)0.33FeF3 and HTBFeF3 are antiferromagnetic, with Néel temperatures of TN = 128°7 ± 0.5 K and TN = 97 ± 2 K, respectively. 相似文献
18.
S.Candeloro de Sanctis N.V. Pavel L. Toniolo 《Journal of organometallic chemistry》1976,108(3):409-421
For the class of compounds mentioned in the title it is difficult to the stucture unambiguously on the molecular and crystal structure of CH3-p)]2 by single crystal X-ray analysis. The crystal data are: M == 743 a.m.u. Space group P21/c. a = 8.510(2), b = 40.652(9), c = 9.762(2) Å, β = 103.61(2)° Dc = 1.50 g/cm3. R = 0.041, R = 0.060, based on 3978 independent reflections. The two π-allylpalladium residues are bridged azenido groups, gaining an approximate square planar coordination around each heavy atom. The two allyl units are stereochemically equivalent, with the central carbon atoms pointing outwars. The rigid triazenido groups force the two palladium atoms into close contact (2.86 Å). The aromatic rings are somewhat rotated with respect to the bonded NNN planes, but some π-conjugation over the whole ligand is still retained. 相似文献
19.
The crystal structure of NbS3 was determined from single-crystal diffractometer data obtained with MoKα radiation. The compound is triclinic, space group , with: a 4.963(2) Å; b = 6.730(2) Å; c = 9.144(4)Å; α = 90°; β = 97.17(1)°; γ = 90°. The structure is closely related to the ZrSe3 structure type; it shows that the compound can be formulated as Nb4+(S2)2?S2?, in agreement with XPS spectra. The main difference with ZrSe3 is that the Nb atoms are shifted from the mirror planes of the surrounding bicapped trigonal prisms of sulfur atoms to form NbNb pairs (NbNb = 3.04 Å); this causes a doubling of the b axis relative to ZrSe3 and a decrease of the symmetry to triclinic. 相似文献
20.
Dimethylaluminium- and dimethylgallium-N,N′-dimethylacetamidine (I and II) are doubly associated forming a puckered eight-membered ring. They crystallize isostructurally in the monoclinic space group P21/c with two dimers per unit cell. The lattice constants of I are a 8.187, b 7.266, c 14.778 Å, β 103.58° and those of II a 8.163, b 7.277, c 14.835 Å, β 103.46°. The MN and the NC bond lengths within the rings are nearly equal, their mean values are for I: AlN 1.925 Å, CN 1.330 Å and for II: GaN 1.979 Å, CN 1.335 Å. This is also true for the exocyclic bond lengths with average values AlC 1.975 Å, NC 1.474 Å, CC 1.509 Å (for I) and GaC 1.998 Å, NC 1.484 Å and CC 1.507 Å (for II). The metal atoms are tetrahedrally coordinated, and the distortion is only slight. The final R-values are 0.034 and 0.056, respectively. 相似文献