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 711 毫秒
1.
Li6[TeMo6O24] · 18 H2O is triclinic (space group P1 , a = 1 041.7(1), b = 1 058.6(1), c = 1 070.8(1) pm, α = 61.08(1), β = 60.44(1), γ = 73.95(1)°). Single crystal X-ray structure analysis (Z = 1, 295 K, 317 parameters, 3 973 reflections, Rg = 0.0250) revealed an infinite branched chain of edge-sharing Li coordination polyhedra to be the prominent structural feature. One of the four crystallographically independent Li+ is coordinated octahedrally. The coordination polyhedra of the remaining Li+ are distorted trigonal bipyramids. Only three unique oxygen atoms (O(9), O(10), O(12)) of the centrosymmetric [TeMo6O24]6? anion are bound to Li+. The further positions in the coordination spheres of the Li+ are occupied by water molecules. Intermolecular hydrogen bonds involve mainly oxygen atoms of the [TeMo6O24]6? anion as nearly equivalent proton acceptors without regard to their different bonding modes to Te and Mo, respectively. Li6[TeMo6O24] · Te(OH)6 · 18 H2O crystallizes monoclinically in space group P21/n with Z = 4, a = 994.1(3), b = 2 344.8(10), c = 1 764.9(4) pm, and β = 91.36(4)°. Single crystal structure analysis with least squares refinement of 627 parameters (5 900 reflections, 295 K) converged to Rg = 0.0324. There are six unique Li+ cations. The coordination polyhedra of Li(1), Li(2), Li(3), and Li(4) are linked by common edges to yield an eight membered centrosymmetric strand. The coordination polyhedra of the remaining two Li+ sites (Li(5), Li(6)) are connected to a dimeric unit via a common corner. All oxygen atoms of the Te(OH)6 molecule are involved in the coordination of Li+. However, only three oxygen atoms (O(13), O(18), O(23)) of the [TeMo6O24]6? anion which lacks crystallographic symmetry are involved in the coordination of Li+. The oxygen atoms of the anion act as proton acceptors in hydrogen bonds of predominantly medium strength. Te(OH)6 molecules and [TeMo6O24]6? anions connected by strong hydrogen bonds form an infinite chain.  相似文献   

2.
On Tantalates ‘rich in Cations’ On Li7[TaO6] For the first time, colourless single crystals of Li7[TaO6] were grown by annealing intimate mixtures of Li2O and Ta2O5 (Li:Ta = 7,7:1) in closed Ni-cylinders (1 000°C, 156 d). [Trigonal-rhomboedral with a = 535.8(1) pm, c = 1 507.3(3) pm, c/a = 2.81/Guinier-Simon-powder data; Z = 3. Space group R3 for the part Li(1)6TaO6 and presumably P3 for Li7TaO6, including Li(2)]. The crystal structure was solved by four-cycle-diffractometer data [Mo? Kα , 331 from 331 Io(hkl), R = 1.99%, Rw = 1.96%], parameters see text. The positions of anions correspond to the motif of a hexagonal closest packing of spheres, obviously deformed (with MEFIR of O2? space filling corresponds to 69.8% instead of expected 73.2%. 1/3 of the octahedron holes are ordered occupied by Ta and Li(2), 1/2 of the tetrahedral holes likewise ordered by Li(1). All polyhedra of coordination of the anions are trigonal prisms. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, as well as charge distribution ‘CHARDI’ are calculated and discussed.  相似文献   

3.
Single crystals of fluoride hydrates Mn3F8 · 12 H2O and AgMnF4 · 4 H2O have been prepared and characterized by X-ray methods. Mn3F8 · 12 H2O crystallizes in the space group P1 (a = 623.0(3), b = 896.7(4), c = 931.8(4) pm, α = 110.07(2)°, β = 103.18(2)°, γ = 107.54(2)°, Z = 1); AgMnF4 · 4 H2O crystallizes in the space group P21/m (a = 700.9(2), b = 726.1(1), c = 749.4(3) pm, β = 107.17(3)°, Z = 2). Both structures contain Jahn-Teller-distorted [Mn(H2O)2F4]? anions as well as crystal water molecules and exhibit a complex hydrogen bond network between anions and cations, i. e. [Mn(H2O)6]2+ for the first and a polymeric [Ag(H2O)2]? cation for the second compound.  相似文献   

4.
New Oxoterbates(IV) with Lithium: On Rb2Li14[Tb3O14] and Li6Tb2O7 For the first time we prepared Rb2Li14[Tb3O14] as yellow single crystals from Li8TbO6 and Rb2O (Tb:Rb = 1:2) [Ag-cylinder, 500°C, 30 d, then Au-tube, 700°C, 27 d]. The structure refinement [652 I0 (h kl), four circle diffractometer Philips PW 1100, ω-scan, MoKα, R = 4.69%, Rw = 3.24%, absorption considered, Immm with a = 1 283.07(10), b = 790.87(7), c = 736.87(7)pm, Z = 2, dx = 4.30 g · cm?3] confirms that it is isotypic with K2Li14[Pb3O14]. Furthermore we got for the first time Li6Tb2O7 as a bright yellow compound from Li2O2 and “Tb4O7*” [(Li:Tb = 3.4:1), Au-ube, 750°C, 13 d (powder), 850°C 22 d (single crystals)] and by thermal decomposition of Rb2Li14[Tb3O14] (Au-tube, 850°C, 25 d). Powder and single crystal data [1 327 I0 (h kl), four circle diffractometer PW 1100, ω-scan, AgKα, R = 9.38%, Rw = 5.23%, absorption not considered, P21/a, a = 1 056.30(10), b = 613.50(4), c = 546.56(5) pm, β = 109.668(7)°, Z = 2, dx = 4.67 g · cm?3 dpyc = 4.53 g · cm?3] reveal a new type of structure that may be deduced by the NaCl-type of structure. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.  相似文献   

5.
Preparation of Crystal Structure of K6[Al2O6] and Rb6[Al2O6] Colourless single crystals of K6[Al2O6] have been prepared from intimate mixtures of KAlO2 and K2O (550°C, 90 d). The structure determination from four-circle diffractometer data (MoKα , 742 Io(hkl), R = 2.2%, Rw = 2.1%) confirms the space group C2/m with Z = 2; a = 698.25 pm, b = 1 103.54 pm, c = 646.49 pm, β = 102.49°. Colourless single crystals of hitherto unknown Rb6[Al2O6] have been prepared from intimate mixtures of RbAlO2 and Rb2O (520°C, 120 d). The structure determination from four-circle diffractometer data (MoKα , 1 240 Io(hkl)) results in the residual values R = 7.2%, Rw = 4.9%; space group C2/m; a = 725.92 pm, b = 1 143.33 pm, c = 678.06 pm, β = 104.05°; Z = 2. K6[Al2O6] and Rb6[Al2O6] are isostructural with K6[Fe2O6]. A characteristic structure unit is the anion [Al2O6]6? consisting of two edge-sharing [AlO4] tetrahedra. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Madelung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHARDI) are calculated and discussed.  相似文献   

6.
Syntheses and Crystal Structures of the Nitrido‐chloro‐molybdates [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 and [Li(12‐Crown‐4)(NMoCl4)]2 · 2 CH2Cl2 Both the title compounds as well as [Li(12‐crown‐4)2]+MoNCl4 were made from MoNCl3 and the chlorides MgCl2 and LiCl, respectively, in dichloromethane suspensions in the presence of tetrahydrofuran and 12‐crown‐4, respectively. They form orange‐red moisture‐sensitive crystals, which were characterized by their IR spectra and partly by crystal structure analyses. [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 ( 1 ): space group C2/m, Z = 2, lattice dimensions at –50 °C: a = 1736.6(1), b = 1194.8(1), c = 1293.5(2) pm; β = 90.87(1)°; R1 = 0.037. In 1 the magnesium ion is coordinated octahedrally by the oxygen atoms of the four THF molecules and in trans‐position by the nitrogen atoms of the two [N≡MoCl4(THF)] ions. [Li(12‐crown‐4)(NMoCl4)]2 · 2 CH2Cl2 ( 2 ): space group P 1, Z = 1, lattice dimensions at –70 °C: a = 930.4(1), b = 957.9(1), c = 1264.6(1) pm; α = 68.91(1)°, β = 81.38(1)°, γ = 63.84(1)°; R1 = 0.0643. 2 forms a centrosymmetric ion ensemble in the dimeric cation of which, i. e. [Li(12‐crown‐4)]22+, the lithium ions on the one hand are connected to the four oxygen atoms each of the crown ether molecules in a way not yet known; and in addition, each of the lithium ions enters into a intermolecular Li–O bond with neighboring crown ether molecules under formation of a Li2O2 four‐membered ring. The two N≡MoCl4 counterions are loosely coordinated to one oxygen atom each of the crown ether molecules with Mo–O distances of 320.2 pm.  相似文献   

7.
Ternary Hydroxides. I. Synthesis, Structure, and Properties of Li2[Sn(OH)6] · 2 H2O Colourless crystals of Li2[Sn(OH)6] · 2 H2O were synthesized by reaction of SnCl4 with LiOH in aqueous solution. The crystal structure was determined from single crystal data. Li2[Sn(OH)6] · 2 H2O: monoclinic, P21/n (Nr. 14), a = 502.3(1), b = 692.3(1), c = 1020.2(3) pm, β = 99.78(1)°, V = 349.6(2) · 106 pm3, Z = 2, R/Rw = 0.0192/0.0472, N(I) > 2σ(I) = 1527, N(Par.) = 54. Within the crystal structure only slightly distorted octahedrally [Sn(OH)6]2? ions are bonded via hydrogen bonds with water molecules forming layers, which themselve are linked by tetrahedrally coordinated Li ions; the structure is in accordance with the IR-data and the results of the 119Sn solid state NMR-spectroscopy; the hydrat water is eliminated at 117.1°C, the condensation reaction – forming the ternary oxide – takes place at 257.7°C.  相似文献   

8.
[Li7(CHPMe2NSiMe3)3(OSiMe2nBu)]2, a Mixed-Ligand-Li14 Cluster with the Carbdianion (CHPMe2NSiMe3)2? The title compound is formed as colourless moisture and oxygen sensitive crystals by the reaction of [LiCH2PMe2NSiMe3]4 with zinc or cobalt chloride in a toluene suspension in the presence of silicongrease (–OSiMe2–)n and n-butyllithium. It is characterized by multinucleus NMR spectroscopy and by crystal structure determinations of two different crystal individuals. 1. Space group P1 , Z = 1, lattice dimensions at ?70 °C: a = 1272.0, b = 1392.6, c = 1417.6 pm, α = 115.33°, β = 96.75°, σ = 106.81°; R = 0.042. 2. Space group P21/n, Z = 2, lattice dimensions at ?50 °C: a = 1424.8, b = 1457.1, c = 1997.0 pm, β = 90.32, R = 0.069.  相似文献   

9.
On Quaternary Oxotungstates (VI). Na6Li2[W2O10] — a Ditungstate For the first time, Na6Li2[W2O10] has been prepared by annealing mixtures of WO3, Na2O and Li2O with W:Na:Li = 1:3:1 [closed Pt-tube in quartz-glass ampoule, 840°C, 60 d (single crystals)]. The colourless crystals are of squatted shape. The structure determination [1813/I0(h kl), four-cycle diffractometer PW 1100 (Fa. Philips), ω-scan, AgKα, R = 8.32%, absorption not considered] confirms the space group P1 with a = 784.66(11), b = 602.53(7) c, = 563.81(11) pm α = 106.784(14)°, β = 114.548(14)°, γ = 91.082(13)°, Z = 2, dx = 4.92 g · cm?3, dpyk = 4.85 g · cm?3. The structure may be described as a distorted derivative of the NaCl-type. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.  相似文献   

10.
The Crystal and the Electronic Structure of La2Li1/2Au1/2O4 The single crystal X‐ray investigation of the compound La2Li1/2AuIII1/2O4 yields a T′‐type structure (Nd2CuO4) with an ordered distribution of LiI and AuIII on the sites with square‐planar coordination (space group Ammm; a = 5.768 Å, b = 5.762 Å, c = 12.466 Å; c/a(b) = 2.165; a(Au–O) = 2.013(3) Å). Though CuIII possesses the same low‐spin d8‐configuration as AuIII, La2Li1/2Cu1/2O4 adopts the ordered T‐structure with strongly elongated CuO6 octahedra. The electronic and structural causes of the different behaviour are discussed.  相似文献   

11.
On the Reaction of Macrocycles with Lanthanoids. I. The Crystal Structure of [Li(thf)][(C22H22N4)2Ce] · THF In THF CeBr3 forms with [(TMTAA)Li2] the paramagnetic doubledecker complex [Li(thf)][(TMTAA)2Ce]. The complex crystallizes with 1 Mol THF per formula unit. The structure was characterized by X-ray single crystal structure analysis (space group C2 (No. 5), z = 6, a = 1741.8(2) pm, b = 1622.1(2) pm, c = 2540.4(3) pm, β = 104.72(1)°). The sandwich-like arrangement of the heterocyclic ligands leads to a quadratic-prismatic coordination of the Ce3+ ion. One macrocyclic ligand is additionally coordinated by a [Li(thf)]+ fragment. The coordination of the Li ion is square pyramidal.  相似文献   

12.
M(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O (M = Mn2+, Co2+) – Two Isotypic Coordination Polymers with Layered Structure Monoclinic single crystals of Mn(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O ( 1 ) and Co(H2O)2(4,4′‐bipy)[C6H4(COO)2]· 2H2O ( 2 ) have been prepared in aqueous solution at 80 °C. Space group P2/n (no. 13), Z = 2; 1 : a = 769.20(10), b = 1158.80(10), c = 1075.00(10) pm, β = 92.67(2)°, V = 0.9572(2) nm3; 2 : a = 761.18(9), b = 1135.69(9), c = 1080.89(9) pm, β = 92.276(7)°, V = 0.9337(2) nm3. M2+ (M = Mn, Co), which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted octahedral fashion by two water molecules, two oxygen atoms of the phthalate anions and two nitrogen atoms of 4,4′‐biypyridine ( 1 : M–O 219.5(2), 220.1(2) pm, M–N 225.3(2), 227.2(2) pm; 2 : Co–O 212.7(2), 213.7(2) pm, Co–N 213.5(3), 214.9(3) pm). M2+ and [C6H4(COO)2)]2? build up chains, which are linked by 4,4′‐biyridine molecules to yield a two‐dimensional coordination polymer with layers parallel to (001).Thermogravimetric analysis in air of 1 indicated a loss of water of crystallization between 154 and 212 °C and in 2 between 169 and 222 °C.  相似文献   

13.
Crystal Structures of the Polytellurides [Ca(DMF)6]Te4, [Sr(15-Crown-5)2]Te4 · H2O, {[BaCl(18-Crown-6)(DMF)2]2[BaCl(18-Crown-6)(DMF) (H2O)]2(Te4)2}, and [Ph3PNPPh3]2Te5 · 2 DMF The title compounds were formed by alkalimetal polytelluride solutions in dimethylformamide (DMF) in the presence of the corresponding counter ions as well as in the presence of 15-crown-5 or 18-crown-6. Single crystals were obtained upon using additional diethylether. [Ca(DMF)6]Te4: Space group C2/c, Z = 4, 1024 observed unique reflections, R = 0.055. Lattice dimensions at ?70°C: a = 1776.1; b = 813.0 c = 2545.9pm; β = 102.90°. The compound consists of centrosymmetric [Ca(DMF)6]2+ ions, in which the calcium ions are octahedrally coordinated by the six oxygen atoms of the DMF molecules, and chain-like Te [Sr)15-crown-5)2]Te4 · H2O: Space group C2/c, Z = 4, 3322 observed unique reflections, R = 0.058. Lattice dimensions at ?70°C: a = 1450.5; b = 1407.3; c = 1660.9 pm; β = 110.22°. The compounds forms centrosymmetric cations [Sr(15-crown-5) 2]2+, in which the Sr2+ ion is sandwich-like surrounded by the ten oxygen atoms of the crown ether molecules, and chain-like Te42? ions, which are associated in the lattice forming polymeric chains. {[BaCl(18-crown-6)(DMF) 2]2[BaCl(18-crown-6)(DMF)· (H2O)] 2(Te4)2}: Space group P1 , Z = 1, 3189 observed unique reflections, R = 0.054. Lattice dimensions at 19°C: a = 986.1; b = 1052.8; c = 2696.4 pm; α = 89.34°; β = 88.68°; γ = 89.56°. The compound consists of chain-like Te ions without symmetry and of the two somewhat different cations [BaCl(18-crown-6)(DMF) 2]22+, in which the Ba2+ ions dimerize via centroysmmetric rings. Along with the six oxygen atoms of the crown ether molecules and the oxygen atoms of the DMF molecules, the oxygen atoms of the DMF and water molecule, respectively, the Ba+ ions achieve coordination number ten. [Ph3PNPPh3]2Te5 · 2DMF: Space group Pc, Z = 2, 5971 observed unique reflections, R = 0.058. Lattice dimensions at 20°C: a = 20°C: a = 1085.2; b = 1287.0; c = 2715.9 pm; β = 90.19°. The compounds consists of [Ph3PNPPh3]+ ions, chain-like Te52? ions, and incorporate DME molecules without bonding interaction. The 52? ions are associate via polymeric chains in which left- and right handed individuals are alternating.  相似文献   

14.
Unusual Coordination Polyhedra around Oxygen in Li4Cl(OH)3 The pseudobinary system LiOH/LiCl was investigated by X-ray methods. Two compounds, Li4Cl(OH)3 and Li2Cl(OH), were obtained. The crystal structure of Li4Cl(OH)3 solved by single-crystal methods is delt with. For Li2Cl(OH) powder diffraction data are given: Li4Cl(OH)3: P21/m, Z = 2, a = 5.4096(8) Å, b = 7.382(2) Å, c = 6.2076(8) Å, β = 94.40(1)°, Z(Fo) with (Fo)2 ≧ 3σ(Fo)2 = 483, Z (parameter) = 50, R/Rw = 0.022/0.025 Li2Cl(OH): Pmma, Z = 2, a = 7.680(8) Å, b = 4.001(7) Å, c = 3.899(6) Å The hydroxide rich compound crystallizes in a new type of structure which contains puckered layers [Li4(OH)3+] connected via chloride ions.  相似文献   

15.
The First Diniobate with ‘Isolated’ Anions: KLi4[NbO5]=K2Li8[Nb2O10] [1] . By heating of well ground mixtures of the binary oxides [K2O, Li2O, Nb2O5, K:Li:Nb=1.1:4.4:1, Pt-tube, 1100°C, 3d] colourless, triclinic single crystals of KLi4NbO5 have been prepared for the first time: space group P1 (Nr. 2) with a=816.9(2) pm, b=592.2(2) pm, c=589.7(2) pm, α=121.00(2)º, β=91.78(2)°, γ=99.23(2)°, Z=2. The crystal structure was solved by four-cycle diffractometer data [Mo-Kα , 1386 from 1386 Io(hkl), R=3.4%, Rw=2.6%], parameters see text. Characteristic for this structure are “isolated” groups of [Nb2O10] and the tetrahedral coordination of Li(1), Li(2), and Li(3). Li(4) has a tetragonal-pyramidal coordination. The structural relations are deduced by Schlegel Diagrams. The Madelung Part of Lattice Energy, MAPLE, the Effective Coordination Numbers, ECoN and the charge distribution have been calculated and discussed.  相似文献   

16.
The crystal structures of two new copper weberites Na2CuGaF7 and Na2CuInF7 have been determined. Na2CuGaF7 has the monoclinic space group C2/c: a = 1232.5(5) pm, b = 731.8(1) pm, c = 1278.0(5) pm, β = 109.29(2)° and Z = 8. Na2CuInF7 crystallizes in the orthorhombic space group Pmnb: a = 731.8(1) pm, b = 1060.2(2) pm, c = 771.2(1) pm and Z = 4. The structures have been refined from 1175 reflections to R = 0.043 (wR = 0.035) for Na2CuGaF7, and from 1917 reflections to R = 0.034 (wR = 0.025) for Na2CuInF7. The structures consist of [CuF5]n3n? chains which are parallel the a-axis in Na2CuInF7 and oriented in two alternating directions in Na2CuGaF7. Sodium atoms exhibit either seven-fold or eight-fold coordination. Although strong antiferromagnetic interactions are observed inside the chains, there is no evidence for three-dimensional ordering.  相似文献   

17.
Synthesis and Structure of [(Ph3C6H2)Te]2, [(Ph3C6H2)Te(AuPPh3)2]PF6 and [(Ph3C6H2)TeAuI2]2 [(2,4,6-Ph3C6H2)Te]2 reacts with Ph3PAu+ to yield [2,4,6-Ph3C6H2TeAuPPh32]PF6 which can be oxidized by I2 to form the gold(III) complex [(2,4,6-Ph3C6H2)TeAuI2]2. [(2,4,6-Ph3C6H2)Te]2 crystallizes in the monoclinic space group P21/c with a = 810.6(2); b = 2026.5(5); c = 2260.6(7) pm; β = 99.23(3)° and Z = 4. In the crystal structure the ditelluride exhibits a dihedral angle C11? Te1? Te2? C21 of 66.1(2)°. The distance Te1? Te2 is 269.45(6) pm. In the cation of the triclinic complex [(2,4,6-Ph3C6H2)Te(AuPPh3)2]PF6 (space group P1 ; a = 1197.4(3); b = 1457.2(4); c = 1680.0(6) pm; α = 84.69(3)°; β = 85.11(3)°; γ = 75.54(3)°; Z = 2) a pyramidal skeleton RTeAu2 with distances Te? Au = 259.2(1) and 257.8(2) pm and Au? Au = 295.3(1) pm is present. [(2,4,6-Ph3C6H2)TeAuI2]2 crystallizes in the triclinic space group P1 with a = 1086.3(3); b = 1462.9(6); c = 1654.2(2) pm; α = 85.25(2)°; β = 87.44(1)°; γ = 80.90(3)°; Z = 2. In the centrosymmetrical dinuclear complex [(2,4,6-Ph3C6H2)TeAuI2]2 the Au atoms exhibit a square-planar coordination by two iodine atoms and two tellurolate ligands. The tellurolate ligands form symmetrical bridges with distances Te? Au = 260.0 pm. The distances Au? I are in the range of 260.3(1) and 263.7(1) pm.  相似文献   

18.
Crystal Structures of the Polyselenides [Cs(18-Crown-6)]2Se5 · DMF, [Rb(222-Crypt)]2Se6, [Ba(15-Crown-5)2]Se6 · DMF, and [Na(12-Crown-4)2]Se7 . The title compounds have been prepared by reactions of the corresponding diselenides with excess selenium in the presence of crown ethers in dimethylformamide solutions, forming black crystals. [Cs(18-Crown-6)]2Se5 · DMF: Space group P21/m, Z = 2, 2 194 observed unique reflections, R = 0.119. Lattice dimensions at 20°C: a = 1 041.2; b = 1 496.3; c = 1 459.7 pm; β = 100.39°. The compound forms an ionic triple with Cs…Se-contacts between 374 and 381 pm. [Rb(222-Crypt)]2Se6: Space group P1 , Z = 2, 7 405 observed unique reflections, R = 0.056. Lattice dimensions at – 70°C: a = 1 106.8; b = 1 460.8; c = 1 718.8 pm; α = 89.22°; β = 86.65°; γ = 71.53°. The compound contains Se62? chains without direct contact with each other. [Ba(15-Crown-5)2]Se6 · DMF: Space group P21/n, Z = 4, 2 680 observed unique reflections, R = 0.055. Lattice dimensions at – 80°C: a = 1 051.9; b = 1 322.4; c = 2 729.9 pm; β = 100.93°. The compound contains Se62? chains, which are isolated from each other by the cations and the included DMF molecules. [Na(12-Crown-4)2]2Se7: Space group P1 , Z = 2, 7 313 observed unique reflections, R = 0.042. Lattice dimensions at – 70°C: a = 1 260.9; b = 1 433.6; c = 1 462.9 pm; α = 80.27°; β = 78.60°; γ = 69.34°. The compound contains Se72? chains without direct contacts with each other.  相似文献   

19.
A New Oxouranate(VI): K2Li4[UO6]. With a Remark about Rb2Li4[UO6] and Cs2Li4[UO6] For the first time K2Li4UO6 has been prepared by an exchange reaction of α-Li6UO6 with K2O [K:U = 2.0:1, sealed au-tube; 750°C; 30 d single crystals; 680°C, 10 d powder]. The irregular shaped single crystals, which are of yellow color and sensitive to moisture crystallize in P3 m1 (Z = 1) with a = 619.27(5), c = 533.76(6) pm. The structure determination (PW 1100, AgKα R = 4.80%, Rw = 4.81% for 220 unique reflexions) reveals a new type of structure. The characteristic elements are the isolated group [UO6] and the C.N. = 12 for K+. While Li(1) has a nearly regular square of 4 O2? as coordination polyhedron, Li(2) is octahedrally surrounded. The Madelung Part of Lattice Energy (MAPLE) is calculated and discussed. In addition to K2Li4[UO6] the new oxides Rb2Li4[UO6] and Cs2Li4[UO6] are prepared as pale yellow powders which are little sensitive to moisture (both: au-tube, 680°C, 10 d). According to powder datas both compounds are isotypic with K2Li4[UO6] [Rb2Li4[UO6]: a = 622.91(5), c = 535.93(6) pm; Cs2Li4[UO6]: a = 626.70(6), c = 539.92(6) pm].  相似文献   

20.
On Barium Hexahydroxoplatinate BaPt(OH)6 · H2O The crystal structure of BaPt(OH)6 · H2O, monoclinic, space group P21/m, a = 628.4, b = 624.6, c = 857.4 pm, β = 108.19°, Z = 2, contains octahedral Pt(OH)6 groups and ninefold-coordinated barium. The water molecules are not coordinated to metal atoms but connected with Pt(OH)6 groups only by very weak hydrogen bonds with oxygen-oxygen distances of 292—296 pm. The compound is dehydrated readily when dried gently. This explains contradictory evidence concerning its water content.  相似文献   

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