首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Single crystals of Pb2P2O7 have been grown by the Czochralski technique. They have the triclinic space group P1 with cell dimensions a = 6.9627 Å, b = 6.9754Å, c = 12.764 Å, α = 96.78°, β = 91.16°, γ = 89.68°. There are four molecules per unit cell. Dielectric properties for this compound have been measured and are discussed.  相似文献   

2.
Ammonium tetrametaphosphate-tellurate dihydrate, (NH4)4P4O12 · 2Te(OH)6 · 2H2O, is triclinic with the following unit cell dimensions: a = 11.845(6), b = 8.554(5), c = 7.433(5) Å, α = 66.28(5), β = 95.91(5), γ = 76.00(5)° space group: P1 and Z = 1. The crystal structure has been determined with a final R value of 0.021. As in the previously described phosphate-tellurates, monophosphate-tellurate and trimetaphosphate-tellurates, the phosphoric anion (here the P4O12 ring) is independent of the octahedral Te(OH)6 group. A complete pattern of the hydrogen bonds is given.  相似文献   

3.
The crystal and molecular structure of Fe3Te2(CO)9 has been determined by X-ray diffraction analysis. The compound crystallizes in the triclinic space group P1 with a 952.5(4), b 1314.3(8), c 694.7(2) pm, α 95.27(4), β 112.78(3), γ 81.44(4)° and Z = 2 (R = 0.036, using 2079 reflections).  相似文献   

4.
The system MgOSiO2H2O was investigated at pressures between 40 and 95 kbar and at temperatures between 500 and 1400°C. The reaction products were examined by X-ray, optical and thermal analysis techniques and the density of phase A discovered by Ringwood and Major was also measured. It was found that phase A was hydrated and its chemical formula was H6Mg7Si2O14. When the MgSi ratio of the system is 2, phase A + clinoenstatite, and forsterite are stable at temperatures lower and higher than a boundary curve T (°C) = 10P (kbar), respectively. When the MgSi ratio of the system is 3, phase A + phase D (which is completely different from the phases, A, B and C discovered by Ringwood and Major, and any other known phases of magnesium silicate) and phase D + brucite are stable at temperatures lower and higher than a boundary curve T(°C) = 10P (kbar) + 200. Phase A has approximately an hexagonal symmetry and the space group and the lattice parameters are determined as P63 or P63m and a = 7.866(2) Å and c = 9.600(3) Å, respectively. The measured density is 2.96 ± 0.02 g/cm3. The optical observations show that phase A is biaxial positive crystal with refractive indices α = 1.638 ± 0.001, β = 1.640 ± 0.002, and γ = 1.649 ± 0.001. Some interpretation is given on the inconsistency between the symmetry determined by the X-ray diffraction and the optical observation. The new phase D belongs to the space group P21c with lattice parameters a = 7.914(2)Å, b = 4.752(1) Å, c = 10.350(2) Å and β = 108.71(5)° and is a biaxial crystal with refractive indices α = 1.630 ± 0.002, β = 1.642 ± 0.002 and γ = 1.658 ± 0.001.  相似文献   

5.
Fe2P2O7 crystallizes in the C1 space group with lattice parameters a = 6.649(2)Å, b = 8.484(2)Å, c = 4.488(1)Å, α = 90.04°, β = 103.89(3)°, γ = 92.82(3)°, and ?cal = 3.86 g/cc. It is essentially isostructural with β-Zn2P2O7. As in the Zn compound, the bridging oxygen atom in the P2O7 group shows a high anisotropic thermal motion. It appears that the P-O-P bond angle is linear as a result of extensive π bonding with the p orbitals on the bridging oxygen atom. The high thermal motion is vibration of the atom into cavities in the structure.  相似文献   

6.
Nickel-ammonium tetrametaphosphate, Ni(NH4)2P4O12 · 7H2O is triclinic with a = 13.841(3); b = 9.621(5); c = 7.482(2)Å; α = 98.05(4); β = 97.25(4); γ = 103.01(4)°; M = 536.59; V = 947.9Å3; Z = 2; Dx = 1.879 g cm?3; μ = 14.524 cm?1, and space group P1. The crystal structure was solved using 1661 independent reflections measured on a single-crystal diffractometer (Mo). The final R value is 0.056. The two crystallographic independent nickel atoms Ni(1) and Ni(2) are octahedrally coordinated: Ni(1) by four oxygen atoms and two water molecules, Ni(2) by six water molecules. Ni(1), closely connected to two P4O12 rings, forms a complex anion [Ni(P4O12)2(H2O)2]6? which is associated to ammonium polyhedra and [Ni(H2O)6]2+ octahedra. Another interesting feature of this atomic arrangement is the presence of a large channel (10 × 4) Å2 parallel to the c axis. The internal surface of this channel is covered by six zeolitic water molecules.  相似文献   

7.
Ce6Mo10O39 crystallizes in the triclinic system with unit-cell dimensions (from single-crystal data) a = 10.148(5), Å, b = 18.764(6), Å, c = 9.566(5), Å, α = 103.12(7)°, β = 78.07(7)°, γ = 107.69(7)°, and space group P1, z = 2. The structure was solved using direct methods with 3113 countermeasured reflections (Mo radiation), and refined using Fourier and least-squares techniques to a conventional R of 0.039 (ωR = 0.047). Ce6Mo10O39 has a structure that consists of isolated MoO4 tetrahedra together with one corner-shared pair of tetrahedra, linked to irregular eight-coordinate Ce(III) polyhedra. The average MoO distance of 1.77 Å, and average CeO distance of 2.52 Å are in good agreement with previously reported values.  相似文献   

8.
A new ruthenium-rhodium mixed-metal cluster HRuRh3(CO)12 and its derivatives HRuRh3(CO)10(PPh3)2 and HRuCo3(CO)10(PPh3)2 have been synthesized and characterized. The following crystal and molecular structures are reported: HRuRh3(CO)12: monoclinic, space group P21/c, a 9.230(4), b 11.790(5), c 17.124(9) Å, β 91.29(4)°, Z = 4; HRuRh3(CO)10(PPh3)2·C6H14: triclinic, space group P1, a 11.777(2), b 14.079(2), c 17.010(2) Å, α 86.99(1), β 76.91(1), γ 72.49(1)°, Z = 2; HRuCo3(CO)10(PPh3)2·CH2Cl2: triclinic, space group P1, a 11.577(7), b 13.729(7), c 16.777(10) Å, α 81.39(4), β 77.84(5), γ 65.56°, Z = 2. The reaction between Rh(CO)4? and (Ru(CO)3Cl2)2 tetrahydrofuran followed by acid treatment yields HRuRh3(CO)12 in high yield. Its structural analysis was complicated by a 80–20% packing disorder. More detailed structural data were obtained from the fully ordered structure of HRuRh3(CO)10(PPh3)2, which is closely related to HRuCo3(CO)10(PPh3)2 and HFeCo3(CO)10(PPh3)2. The phosphines are axially coordinated.  相似文献   

9.
LLi2Mo4o13 crystallizes in the triclinic system with unit-cell dimensions a = 8.578 Å, b = 11.450 Å, c = 8.225 Å, α = 109.24°, β = 96.04°, γ = 95.95° and space group P1, Z = 3. The calculated and measured densities are 4.02 g/cm3 and 4.1 g/cm3 respectively. The structure was solved using three-dimensional Patterson and Fourier techniques. Of the 2468 unique reflections collected by counter methods, 1813 with I ? 3σ(I) were used in the least-squares refinement of the model to a conventional R of 0.031 (ωR = 0.038). LLi2Mo4O13 is a derivative of the V6O13 structure with oxygen ions arranged in a face-centred cubic type array with octahedrally coordinated molybdenum and lithium ions ordered into layers.  相似文献   

10.
The structure of a KxP2W4O16 (x ? 0.4) crystal was established by X-ray analysis. The solution in the cell of symmetry P21m, with a = 6.6702(5), b = 5.3228(8), c = 8.9091(8) Å, β = 100.546(7)°, Z = 1, has led to R = 0.033 and Rw = 0.036 for 2155 reflections with σ(I)I ≤ 0.333. This structure can be described as two octahedra-wide ReO3-type slabs connected through “planes” of PO4 tetrahedra. A new structural family KxP2W2nO6n+4 can be foreseen which is closely related to the orthorhombic P4W8O32 and the monoclinic RbxP8W8nO24n+16 series.  相似文献   

11.
Single crystals of the title compounds have been grown by the Czochralski technique. Pb4P2O9 crystallizes in the space group P21c with the parameters a = 9.4812 Å, b = 7.1303 Å, c = 14.390 Å, β = 104.51° and Pb8P2O13 in C2m with a = 10.641 Å, b = 10.206Å c = 14.342 Å, β = 98.34°.  相似文献   

12.
Diphenylcyclopropenethione reacts with Fe2(CO)9 in THF to give tetracarbonyl(diphenylcyclopropenethione)iron (C3Ph2S)Fe(CO)4. The crystal structure was determined by single crystal X-ray analysis. The compound crystallizes in the triclinic space group P1 with lattice constants a 1520.3(5), b 1026.1(3), c 933.5(2) pm; α 120.58(2), β 109.36(2), γ 111.72(2)°; Z 2. The molecule consists of an unchanged diphenylcyclopropenethione ligand coordinated via the sulphur atom to an Fe(CO)4 group in the axial position. The CS distance is 165.2(7) pm with an FeSC angle of 111.2(2)°.  相似文献   

13.
The new compound Tl6[Ge2Te6] was prepared by thermal synthesis from the elements. The material is triclinic, space group P1, with a = 9.471(2), b = 9.714(2), c = 10.389(2) Å, α = 89.39(1), β = 97.27(1), γ = 100.79(1)°, and Z = 2. The crystal structure was determined from single-crystal intensity data measured by means of an automated four-circle diffractometer and refined to an R value of 0.053 for 1831 observed reflections. Tl6[Ge2Te6] is characterized by Ge2Te6 units with GeGe bonds which are linked into a three-dimensional structure by Tl atoms coordinated to essentially six Te atoms. The most important mean distances are dGeGe) = 2.456 Å, d(GeTe) = 2.573 Å, and d(TlTe) = 3.515Å. The lone 6s electron pairs of the thallium(I) atoms exhibit significant stereochemical activity. Tl6[Ge2Te6] represents a new structure type.  相似文献   

14.
Three anhydrous polymorphs of cupric iodate, two hydrates, and the basic iodate salesite have been investigated. α-Cu(IO3)2 is monoclinic, space group P21, with a = 5.551 ± 0.008, b = 5.101 ± 0.004, c = 9.226 ± 0.010 Å and β = 95°4′ ± 11′, with two formulas in the unit cell. Below ΘN = 8.5 K, α-Cu(IO3)2 is antiferromagnetic and also pyroelectric. β-Cu(IO3)2 is triclinic, space group P1, with a = 11.230 ± 0.006, b = 11.368 ± 0.009, c = 10.630 ± 0.009 Å, α = 99°18.3′ ± 0.3′, β = 107°0.4′ ± 0.2′ and γ = 114°23.8′ ± 0.2′ and eight formulas per unit cell: the crystal is paramagnetic to 1.4K. γ-Cu(IO3)2 is monoclinic, space group P21m, with a = 4.977 ± 0.004, b = 6.350 ± 0.004, c = 8.160 ± 0.004 Å and β = 92°20′ ± 4′, with two formulas per unit cell; γ-Cu(IO3)2 becomes antiferromagnetic below ΘN = 5 K. Cu(IO3)2·2H2O is monoclinic, space group P21c, with a = 6.725 ± 0.005, b = 4.770 ± 0.007, c = 11.131 ± 0.013 Å and β = 103°1′ ± 4′, with two formulas per unit cell; Cu(IO3)2·2H2O is paramagnetic to 1.4 K. Cu(IO3)2·23H2O (mineral bellingerite) is triclinic, space group P1, with a = 7.197 ± 0.005, b = 7.824 ± 0.004, c = 7.904 ± 0.004 Å, α = 105°2′ ± 2′, β = 97°7′ ± 2′ and γ = 92°54′ ± 2′ with three formulas per unit cell; this crystal is paramagnetic to 1.4 K, with a moderate antiferromagnetic Cu-Cu interaction. Cu(OH)IO3 (mineral salesite) is orthorhombic, with a = 10.772 ± 0.004, b = 6.702 ± 0.002 and c = 4.769 ± 0.002 Å and four formulas per unit cell. The magnetic susceptibility indicates the possibility of antiferromagnetic ordering at 162 K; strong antiferromagnetic interactions give Θp = ?340 K. The only copper iodate studied that generates second harmonics is α-Cu(IO3)2. Indexed powder patterns are given for all six compounds.  相似文献   

15.
The crystal structure of KxP4W14O50 (x = 1.4) has been solved by three-dimensional single crystal X-ray analysis. The refinement in the cell of symmetry A2m, with a = 6.660(2) Å, b = 5.3483(3) Å, c = 27.06(5) Å, and β = 97.20(2)°, Z = 1, has led to R = 0.036 and Rw = 0.039 for 2436 reflections with σ(I)I ≤ 0.333. This structure belongs to the structural family KxP4O8(WO3)2m, called monophosphate tungsten bronzes (MPTB), which is characterized by ReO3-type slabs of various widths connected through PO4 single tetrahedra. This bronze corresponds to the member m = 7 of the series and its framework is built up alternately of strands of three and four WO6 octahedra. The structural relationships with the P4O8(WO3)2m series, called M′PTB, are described and the possibility of intergrowth between these two structures is discussed.  相似文献   

16.
Ce2(MoO4)2(Mo2O7) crystallizes in the triclinic system with unit cell dimensions (from single-crystal data) a = 11.903(8), b = 7.509(5), c = 7.385(5) Å, α = 94.33(8), β = 97.41(8), γ = 88.56(7)°, and space group P1, z = 2. The structure was solved using Patterson (“P1 method”) and Fourier techniques. Of the 8065 unique reflections measured by counter techniques, 6314 with I ≥ 3σ(I) were used in the least-squares refinement of the model to a conventional R of 0.035 (Rw = 0.034). The structure of Ce2(MoO4)2(Mo2O7) consists of dimolybdate chains of the K2Mo2O7 and (NH4)2Mo2O7 type separated by isolated MoO4 tetrahedra and cerium(III) polyhedra.  相似文献   

17.
The carbido dianion [Os10C(CO)24]2? reacts with NOBF4 in MeCN to give [OS10C(CO)242-NO)]? (1) in which the nitrosyl ligand adopts a novel bonding mode bridging the wingtips of a “butterfly” indentation of metal atoms. The anion 1 undergoes rearrangement and CO loss in solution to give [OS10C(CO)23(NO)]? (2); the overall molecular geometry of 2 is close to that previously found for the dianion [Os10C(CO)24]2? with the nitrosyl ligand bonded in a terminal fashion to the tetrahedral Os10 metal skeleton. Crystals of the [(Ph3P)2N]+ salt of 1 are triclinic, space group P1, with a 20.389(4), b 14.670(3), c 12.333(3) Å, α 99.55(3), β 94.43(3), γ 103.03(3)°, Z = 2, refinement of atomic parameters using 2699 absorption corrected data converged at R = 0.0952. The [(Ph3P)2N]+ salt of 2 crystallises with one molecule of CH2Cl2 in the triclinic space group P1, with a 19.374(3), b 16.813(3), c 11.791(2) Å, α 85.00(3), β 101.81(3), γ 99.43(3)°, Z = 2, refinement of atomic parameters using 8736 absorption corrected data converged at R = 0.0943.  相似文献   

18.
Ba2V2O7 is triclinic with a = 13.571(3), b = 7.320(2), c = 7.306(2) Å, α = 90.09(1), β = 99.48(1), β = 99.48(1), γ = 87.32(1)°, V = 7.15.1 Å3, Z = 4, and space group P1. The crystal structure was solved by Patterson and Fourier methods and refined by full-matrix least-squares analysis to a Rw of 0.034 (R = 0.034) using 2484 reflections measured on a Syntex P1 automatic four-circle diffractometer. The structure has two unique divanadate groups that are repeated by the b and c lattice translations to form sheets of divanadate groups parallel to (100). These sheets are linked by four unique Ba atoms that lie between these sheets. Ba(1) and Ba(3) are coordinated by eight oxygens arranged in a distorted biaugmented triangular prism and a distorted cubic antiprism, respectively. Ba(2) is coordinated by 10 oxygens arranged in a distorted gyroelongated square dipyramid and Ba(4) is coordinated by nine oxygens arranged in a distorted triaugmented triangular prism. These coordination numbers are substantiated by a bond strength analysis of the structure, and the variation in 〈BaO〉 distances is compatible with the assigned cation and anion coordination numbers. Both divanadate groups are in the eclipsed configuraton with 〈VO(br)〉 bond lengths of 1.821(4) and 1.824(4) Å and VO(br)V angles of 125.6(3) and 123.7(3)°, respectively. Examination of the divanadate groups in a series of structures allows certain generalizations to be made. Longer 〈VO(br)〉 bond lengths are generally associated with smaller VO(br)V angles. When VO(br)V < 140°, the divanadate group is generally in an eclipsed configuration; when VO(br)V > 140°, the divanadate group is generally in a staggered configuration. Nontetrahedral cations with large coordination numbers require more oxygens with which to bond, and hence O(br) is more likely to be three coordinate, with the divanadate group in the eclipsed configuration. In the eclipsed configuration, decrease in VO(br)V promotes bonding between O(br) and nontetrahedral cations, and hence smaller nontetrahedral cations are generally associated with smaller VO(br)V angles.  相似文献   

19.
The crystal structure of β-BiNbO4 has been determined from three-dimensional X-ray data. The crystals are triclinic with a = 7.611 Å, b = 5.536 Å, c= 7.919 Å, α = 89.88°, β = 77.43°, γ = 87.15°, Z = 4, space group P1. Full-matrix least-squares refinement using isotropic temperature factors has reached R = 0.122 for 642 visually estimated reflections.The structure contains unusual sheets of formula [NbO4] in which the NbO octahedra are joined at four vertices such that the two free ones are cis. NbO distances range from 1.80 to 2.31 Å. The bismuth atoms hold these sheets together and are coordinated to eight oxygens in the form of a very distorted square antiprism.Structurally, β-BiNbO may be considered an antiferroelectric, ferroelastic member of the BaMF4 prototype family.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号