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 0 毫秒
1.
Structure, Twinning, and Properties of Ce4Br3C4 The new compound Ce4Br3C4 can be prepared from Ce metal, CeBr3 and C (3 : 3 : 2) at 1020 °C. It crystallizes in P 1 with a = 422.7(1) pm, b = 1103.4(3) pm, c = 1126.8(2) pm, α = 77.15(3)°, β = 90.13(2)° and γ = 84.42(3)°. The crystals are characteristically twinned, the twin law being (1 0 0, 1/2 –1 0, 0 0 –1). The crystal structure contains puckered layers of edge sharing Ce6C2 octahedra. The mean C–C distance in the C2 units is 133(5) pm. Ce4Br3C4 has at room temperature a specific resistivity of 100 mΩ cm and an effective magnetic moment of 2.55(3) μB (Ce3+).  相似文献   

2.
Crystal Structures of SeCl3+SbCl6?, SeBr3+GaBr4?, PCl4+SeCl5?, and (PPh4+)2SeCl42? · 2 CH3CN The crystal structures of the title compounds were determined by X-ray diffraction. SeCl3+SbCl6?: Space group P21/m, Z = 4, structure determination with 1795 observed unique reflections, R = 0.022. Lattice dimensions at ?80°C: a = 940.9, b = 1066.3, c = 1234.9 pm, β = 102.79°. The compound forms ion pairs with the structure of a double octahedron with linked surfaces. SeBr3+GaBr4?: Space group Pc, Z = 2, structure determination with 1461 observed unique reflections, R = 0.058. Lattice dimensions at ?60°C: a = 660.1, b = 655.3, c = 1431.3 pm, β = 101.177°. The compound crystallizes in the SCl3[AlCl4] lattice type. Between the ions there are two relatively short Se … Br? Ga contacts. PCl4+SeCl5?: Space group Ima2, Z = 8, structure determination with 1757 observed unique reflections, R = 0.029. Lattice dimensions at ?50°C: a = 1651.6, b = 1201.2, c = 1166.4 pm. The SeCl5? ions are associated to chains via interionic Se? Cl … Se contacts along the crystallographic c-axis. (PPh4+)2SeCl42? · 2CH3CN: Space group P21/n, Z = 2, structure determination with 2578 observed unique reflections, R = 0.050. Lattice dimensions at ?80°C: a = 1288.5, b = 726.0, c = 2585.8 pm, β = 101.65°. The compound includes planar-tetragonal SeCl42? ions, which almost meet D4h symmetry.  相似文献   

3.
Rare Earth Halides Ln4X5Z. Part 1: C and/or C2 in Ln4X5Z The compounds Ln4X5Cn (Ln = La, Ce, Pr; X = Br, I and 1.0 < n < 2.0) are prepared by the reaction of LnX3, Ln metal and graphite in sealed Ta‐ampoules at temperatures 850 °C < T < 1050 °C. They crystallize in the monoclinic space group C2/m. La4I5C1.5: a = 19.849(4) Å, b = 4.1410(8) Å, c = 8.956(2) Å, β = 103.86(3)°, La4I5C2.0: a = 19.907(4) Å, b = 4.1482(8) Å, c = 8.963(2) Å, β = 104.36(3)°, Ce4Br5C1.0: a = 18.306(5) Å, b = 3.9735(6) Å, c = 8.378(2) Å, β=104.91(2)°, Ce4Br5C1.5: a = 18.996(2) Å, b = 3.9310(3) Å, c = 8.282(7) Å, β = 106.74(1)°, Pr4Br5C1.3: a = 18.467(2) Å, b = 3.911(1) Å, c = 8.258(7) Å, β = 105.25(1)° and Pr4Br5C1.5: a = 19.044(2) Å, b = 3.9368(1) Å, c = 8.254(7) Å, β = 106.48(1)°. In the crystal structure the lanthanide metals are connected to Ln6‐octahedra centered by carbon atoms or C2‐groups. The Ln6‐octahedra are condensed via opposite edges to chains and surrounded by X atoms which interconnect the chains. A part n of isolated C‐atoms is substituted by 1‐n C2‐groups. The C‐C distances range between 1.26 and 1.40Å. In the ionic formulation (Ln3+)4(X?)5(C4?)n(C2m?)1?n·e? with 0 < n < 1 and m = 2, 4, 6 (C22?, C24? C26?), there are 1 < e? < 5 electrons centered in metal‐metal bonds.  相似文献   

4.
Sheets of La6(C2) Octahedra in Lanthanum Carbide Chlorides – undulated and plane The reaction of Ln, LnCl3 (Ln = La, Ce) and C yields the hitherto unknown compounds La8(C2)4Cl5, Ce8(C2)4Cl5, La14(C2)7Cl9, La20(C2)10Cl13, La22(C2)11Cl14, La36(C2)18Cl23 and La2(C2)Cl. The gold‐ resp. bronze‐coloured metallic compounds are sensitive to moisture. The reaction temperatures are 1030 °C, 1000 °C, 970 °C, 1020 °C, 1020 °C, 1080 °C and 1030 °C in the order of compounds given, which mostly crystallize in the monoclinic space group P21/c with a = 7.756(1) Å, b = 16.951(1) Å, c = 6.878(1) Å, β = 104.20(1)° (La8(C2)4Cl5), a = 7.669(2) Å, b = 16.784(3) Å, c = 6.798(1) Å, β = 104.05(1)° (Ce8(C2)4Cl5), a = 7.669(2) Å, b = 16.784(3) Å, c = 6.789(1) Å, β = 104.05(3)° (La20(C2)10Cl13), a = 7.770(2) Å, b = 47.038(9) Å, c = 6.901(1) Å, β = 104.28(3)° (La22(C2)11Cl14) and a = 7.764(2) Å, b = 77.055(15) Å, c = 6.897(1) Å, β = 104.26(3)° (La36(C2)18Cl23), respectively. La14(C2)7Cl9‐(II) crystallizes in Pc with a = 7.775(2) Å, b = 29.963(6) Å, c = 6.895(1) Å, β = 104.21(3)° and La2(C2)Cl in C2/c with a = 14.770(2) Å, b = 4.187(1) Å, c = 6.802(1) Å, β = 101.50(3)°. The crystal structures are composed of distorted C2 centered La‐octahedra which are condensed into chains via common edges. Three and four such chains join into ribbons, and these are connected into undulated layers with Cl atoms between them. The variations of the structure principle are analyzed systematically.  相似文献   

5.
6.
7.
Rb{Pr6(C)2}I12 was obtained from a mixture of RbI, PrI3, Pr and C as black single crystals at elevated temperatures. The black crystals are triclinic, (no. 2), a = 960.1(2), b = 957.0(2), c = 1003.4(2) pm, α = 71.74(2), β = 70.69(2), γ = 72.38(2)°, V = 805.6(3) 106 pm3, Z = 1; R1 = 0.0868 for all 2749 measured independent reflections. Rb{Pr6(C)2}I12 contains {Pr6(C2)} clusters isolated from each other, surrounded by twelve edge‐bridging and six terminal ligands. The [{Pr6(C)2}Ii12Ia6]? units are connected via i‐a/a‐i bridges according to {Pr6C2}Ii6/1Ii‐a6/2Ia‐i6/2 with rubidium ions occupying twelve‐coordinate interstices.  相似文献   

8.
A substitutional study of the layered, trinuclear metal cluster system, Ta3–xNbxTeI7 (0 ≤ x ≤ 3), has been performed. Synthetic, crystallographic, and spectroscopic results are presented for starting compositions corresponding to the x values: 1, 1.5, and 2. For the entire composition range studied, Ta(Nb) could readily substitute into the Nb(Ta)3TeI7 structure, but with changes in the observed stacking arrangements of the layers as x varies. For tantalum‐rich (x ≤ 1.8) phases, the structure conformed to the Nb3SeI7 structure type, also adopted by Ta3TeI7 and one polytype of Nb3TeI7. Niobium‐rich (i. e. x ≥ 1.7) phases were observed to adopt two structure types according to X‐ray powder diffraction, but crystals could only be obtained for the Nb3SBr7 structure type, which is a second modification of Nb3TeI7. Extended Hückel calculations are used to discuss the distribution of metal clusters in this system.  相似文献   

9.
Pr30Ti24I8O25Se58: A Highly Symmetric Structure with Isolated [Ti6(O)Se8]‐Cluster Units Black crystals of Pr30Ti24I8O25Se58 have been prepared by the reaction of Pr2Se3, Pr2O2Se, TiSe2–x, and I2 at 900 °C. Its crystal structure can be described as a variation of the NaCl structure type (space group Fm 3 m, a = 2319.91(15) pm, Z = 4). The compound contains the first example of a [Ti6(O)Se8] cluster. These clusters form a cubic close packing, where the octahedral and tetrahedral holes are occupied by “superoctahedral” and “supertetrahedral” building units, respectively.  相似文献   

10.
Structures of New Bis(pentafluorophenyl)halogeno Mercurates [{Hg(C6F5)2}3(μ‐X)] (X = Cl, Br, I) From the reactions of [PNP]Cl or [PPh4]Y (Y = Br, I) with Hg(C6F5)2 crystals of the composition [Cat][{Hg(C6F5)2}3X] (Cat = PNP, X = Cl ( 1 ); Cat = PPh4, X = Br ( 2 ), I ( 3 )) are formed. 1 crystallizes in the triclinic space group P1¯, 2 and 3 crystallize isotypically in the monoclinic space group C2/c. In the crystals the halide anions are surrounded by three Hg(C6F5)2 molecules. The reaction of [PPh4]Br with Hg(C6F5)2 under slightly changed conditions gives the compound [PPh4]2[{Hg(C6F5)2}3(μ‐Br)][{Hg(C6F5)2}2(μ‐Br)] ( 4 ).  相似文献   

11.
The first Te–Mn–CO clusters were obtained by the thermal reaction of K2TeO3 with [Mn2(CO)10] in MeOH. The basicity of the μ4-Te ligand in the octahedral cluster anion [(μ4-Te)2Mn4(CO)12]2− is demonstrated by its binding to the fragment [(TeMe2)Mn(CO)4]+ in an axial fashion to afford the novel cluster 1 .  相似文献   

12.
Ag3Bi14Br21: a Subbromide with Bi24+ Dumbbells and Bi95+ Polyhedra – Synthesis, Crystal Structure and Chemical Bonding Black crystals of Ag3Bi14Br21 = (Bi95+)[Ag3Bi3Br153?](Bi2Br62?), the first argentiferous bismuth subhalide, were obtained from a stoichiometric melt of Ag, Bi, and BiBr3. The compound crystallizes in the monoclinic space group P21/m with lattice parameters a = 1277.78(5) pm, b = 1466.87(6) pm, c = 1342.62(5) pm, and β = 108.47(1)° at 110(5) K. In contrast to all other bismuth subhalides that contain an electron‐rich transition metal, the silver atoms are not bonded to bismuth atoms. Instead they are integrated into the anionic bromometallate network, which consists of [MBr6]‐octahedra (M = Ag, Bi) that share edges and vertices. These corrugated sheets alternate with tessellated layers formed by Bi95+ polycations and hitherto unknown (BiII2Br6)2? groups. The latter anions contain Bi24+ dumbbells (299 pm) and can be represented by the structured formula [Br2BiII(μ–Br)2BiIIBr2]2?. The multi‐center bonding within the Bi95+ cluster and the bent single‐bond in the Bi2 dumbbell can be visualized using the electron localization indicator (ELI‐D).  相似文献   

13.
14.
The novel mercury‐tellurium cluster [Hg8(μ‐n‐C3H7Te)122‐Br)Br3] is formed during the reaction of HgBr2 and (n‐C3H7Te)2Hg in DMSO. Its crystal structure has been elucidated showing [Hg8(μ‐n‐C3H7Te)122‐Br)]3+ units with a bromine‐centered distorted Hg8 cube. The mercury atoms are bridged by n‐C3H7Te ligands and the resulting clusters are linked to a three‐dimensional network by bromine atoms. The close packing of the cluster is mainly determined by the flexible n‐propyl residues of the telluride building blocks.  相似文献   

15.
The intermetalloid clusters [M2Bi12]4+ (M = Ni, Rh) were synthesized as halogenido‐aluminates in Lewis‐acidic ionic liquids. The reaction of bismuth and NiCl2 in [BMIm]Cl · 5AlCl3 (BMIm = 1‐butyl‐3‐methylimidazolium) at 180 °C yielded black, triclinic (P1 ) crystals of [Ni2Bi12][AlCl4]3[Al2Cl7]. Black, monoclinic (P21/m) crystals of [Rh2Bi12][AlBr4]4 precipitated after dissolving the cluster salt Bi12–xRhX13–x (X = Cl, Br; 0 < x < 1) in [BMIm]Br·4.1AlBr3 at 140 °C. In the cationic cluster [Ni2Bi12]4+, the nickel atoms center two base‐sharing square antiprisms of bismuth atoms (symmetry close to D4h). The valence‐electron‐poorer rhodium‐containing cluster is a distorted variant of this motif: the terminating Bi4 rings are folded to bicyclic “butterflies“ and the central square splits into two dumbbells (symmetry close to D2h). DFT‐based calculations and real‐space bonding analyses place the intermetalloid units between a triple‐decker complex and a conjoined Wade‐Mingos cluster.  相似文献   

16.
[PtIn6][GaO4]2 – The First Oxide Containing [PtIn6] Octahedra. Preparation, Characterisation, and Rietveld Refinement – With a Remark to the Solid Solution Series [PtIn6][GaO4]2‐x[InO4]x (0 < x ≤ 1) The novel oxides [PtIn6][GaO4]2–x[InO4]x (0 < x ≤ 1) are formed by heating intimate mixtures of Pt, In, In2O3, and Ga2O3 in the corresponding stoichiometric ratio in corundum crucibles under an atmosphere of argon (1220 K, 70 h). The compounds are black, stable in air at room temperature, reveal a semiconducting behaviour, and decompose only in oxidizing acids. X‐ray powder diffraction patterns can be indexed by assuming a face centered cubic unit cell with lattice parameters ranging from a = 1001.3(1) pm (x = 0) to a = 1009.3(1) pm (x = 1). According to a Rietveld refinement [PtIn6][GaO4]2 crystallizes isotypic to the mineral Pentlandite (Fm3m, Z = 4, R(profile) = 6.11%, R(intensity) = 3.95%). The characteristic building units are isolated [PtIn6]10+ octahedra which are linked via [GaO4]5– tetrahedra to a three dimensional framework. Starting from [PtIn6][GaO4]2 the substitution of Ga3+ ions by larger In3+ ions leads to the formation of a solid solution series according to the general formula [PtIn6][GaO4]2–x[InO4]x and becomes apparent in an increase of the lattice parameter.  相似文献   

17.
1,4‐Di(isopropyl)‐1,4‐diazabutadiene as a Reagent for the Trapping of Monomeric Fragments of the Tetragalliumcluster Ga4[C(SiMe3)3]4 – Formation of an Unsaturated GaN2C2 Heterocycle and an Oxidation Product Containing a Ga‐O‐O‐Ga Group The tetrahedral tetragallium cluster Ga4[C(SiMe3)3]4 ( 1 ) dissociates upon dissolution to yield the monomeric fragments Ga‐R [R = C(SiMe3)3]. These monomers could be trapped now by the treatment of their solutions with 1,4‐di(isopropyl)‐1,4‐diazabutadiene. The product of the cycloaddition reaction ( 2 ) possesses a five‐membered GaN2C2 heterocycle with a coordinatively unsaturated gallium atom and an endocyclic C=C double bond. 2 is rather sensitive towards oxidation by traces of air. The contact with oxygen yielded a digallium peroxide [(C2N2iPr2)RGa‐O‐O‐GaR(C2N2iPr2)] ( 3 ) which was isolated in a very low yield only and which has a gallium atom attached to each oxygen atom of the inner peroxo group. Both chelating ligands of 3 possess an unpaired electron.  相似文献   

18.
Cs10Tl6TtO4 (Tt = Si, Ge) and Cs10Tl6SnO3 were synthesized by the reaction of appropriate starting materials at 623–673 K, followed by fast cooling or quenching to room temperature, in arc‐welded tantalum ampoules. According to single‐crystal X‐ray analyses, the compounds crystallize in new structure types (Cs10Tl6TtO4 (Tt = Si, Ge), P21/c and Cs10Tl6SnO3, Pnma), consisting of [Tl6]6– clusters, which can be characterized as distorted octahedra compressed along one of the fourfold axes of an originally unperturbed octahedron, and [SiO4]4–, [GeO4]4– or [SnO3]4– anions. The oxotetrelate thallides can be regarded as “double salts”, which consist of Cs6Tl6 on one side and respective oxosilicates, ‐germanates and ‐stannates on the other, showing almost not any direct interaction between the two anionic moieties, as might be expressed e.g. by the formula [Cs6Tl6][Cs4SiO4]. In contrast to the silicon and germanium compounds, where the oxidation state of the tetrel atom is unambiguously 4+, for the threefold coordinated tin atom in Cs10Tl6SnO3 an oxidation state of 2+ has to be assumed. Thus, the latter reveal further evidence that the so called “hypoelectronic” [Tl6]6– cluster does not require additional electrons and is intrinsically stable. The distortion of [Tl6]6– can be understood in terms of the Jahn–Teller theorem. According to magnetic measurements all title compounds are diamagnetic.  相似文献   

19.
Cs4[Sc6C]Cl13 and Cs4[Pr6(C2)]I13 — Two Examples for the Missing Link in the Connectivity of [M6Z]X X Building Units Cs4[Sc6C]Cl13 (tetragonal, I41/amd, a = 1 540.5(4), c = 1 017.9(7) pm, c/a = 0.661, Z = 4, R = 0.038, Rw = 0.026) and Cs4[Pr6(C2)]I13 (a = 1 804.9(3), c = 1 259.5(3) pm, c/a = 0.698, R = 0.106, Rw = 0.068) are obtained as green-black and blue-black single crystals with brass-like metallic lustre through metallothermic reduction of ScCl3 and PrI3, respectively, with cesium in the presence of carbon in sealed tantalum containers. The, overall, isotypic compounds contain isolated [Sc6C] and [Pr6(C2)] clusters, respectively, that are surrounded by 18 halide (X) ligands (12 Xi and 6 Xa; X = Cl or I). The connection is carried out via the motif [M6Z]XXXX (M = Sc and Pr; Z = C and C2, respectively) and is thereby the missing link of the motifs of connection for the composition Ax[M6Z]X13. Analogous interconnection of [TiO6] octahedra is found in the anatase-type of structure of TiO2.  相似文献   

20.
[Li(THF)4][[NN]2Nd2Cl25-O)Li3] ( 2 ) ([NN]3– = ([Me3SiNCH2CH2)3N]3–) was prepared by transmetallation of Li3[NN] with anhydrous neodymium trichloride in THF. After recrystallization from diethylether/pentane (1 : 2) light blue crystals of 2 were obtained, which were characterized by single crystal X-ray diffraction. Space group: P21/n, Z = 4, lattice dimensions at 203 K: a = 1260.8(3), b = 3832.5(8), c = 1569.2(3) pm, β = 106.07(3)°, R1 = 0.0541. In the anion of 2 a nearly trigonal bipyramidal [Nd2Li35-O)]7+ unit is observed.  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