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.
Preparation and Crystal Structure of (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Ce, Pr, Nd) The complex water containing chlorides (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Ce, Pr, Nd) were prepared for the first time, and the crystal structures of (4-Picolinium)[LnCl4(H2O)3] (Ln = La, Pr) were determined on single crystals by X-ray methods. The isotypic compounds crystallize with triclinic symmetry, space group P1 , Z = 2. Surprisingly there exist the dimeric complex anions [Ln2Cl8(H2O)6]2? (Ln = La, Pr).  相似文献   

2.
Synthesis and Crystal Structures of Lanthanide Bromide Thiosilicates Ln3Br[SiS4]2 (Ln = La, Ce, Pr, Nd, Sm, Gd) Single crystals of the bromide—thiosilicates Ln3Br[SiS4]2 were prepared by reaction of lanthanide metal (Ln = La, Ce, Pr, Nd, Sm, Gd), sulfur, silicon and bromine in quartz glass tubes. The thiosilicates crystallize in the monoclinic spacegroup C2/c (Z = 4) isotypically to the iodide analogues Ln3I(SiS4)2 and the A—type chloride—oxosilicates Ln3Cl[SiO4]2 with the following lattice constants: La3Br[SiS4]2: a = 1583.3(4) pm, b = 783.0(1) pm, c = 1098.2(3) pm, β = 97.33(3)° Ce3Br[SiS4]2: a = 1570.4(3) pm, b = 776.5(2) pm, c = 1092.2(2) pm, β = 97.28(2)° Pr3Br[SiS4]2: a = 1562.6(3) pm, b = 770.1(2) pm, c = 1088.9(2) pm, β = 97.50(2)° Nd3Br[SiS4]2: a = 1561.4(4) pm, b = 766.0(1) pm, c = 1085.3(2) pm, β = 97.66(3)° Sm3Br[SiS4]2: a = 1555.4(3) pm, b = 758.5(2) pm, c = 1079.9(2) pm, β = 98.28(2)° Gd3Br[SiS4]2: a = 1556.5(3) pm, b = 750.8(1) pm, c = 1074.5(2) pm, β = 99.26(2)° In the crystal structures the bromide ions form chains along [001] with trigonal planar coordination by lanthanide cations, while the [SiS4]4‐—building units display isolated distorted tetrahedra.  相似文献   

3.
4.
The First Pyridylbenzimidazolates of the Lanthanides: Syntheses, Crystal Structure and Thermal Decomposition of NH4[Ln(N3C12H8)4] with Ln = Nd, Yb Transparent yellow crystals of the compounds NH4 [LnIII (N3C12H8)4] with Ln = Nd, Yb were obtained by solvent‐free reactions of the lanthanides neodymium and ytterbium with 2‐(2‐Pyridyl)‐benzimidazole. The bulk syntheses lead to isotypic compounds despite the different ionic radii of NdIII and YbIII exhibiting nitrogen coordination of the lanthanides only. Both compounds were investigated IR‐ and Raman‐spectroscopically and in regard to their thermal behaviour. They are the first examples of completely solvent‐free (coordinating and non‐coordinating) compounds of the lanthanides with a complete N‐coordination that were obtained via a solid‐state reaction method.  相似文献   

5.
Preparation and Structure of LnNb7O19 (Ln = La, Ce) Two new ternary compounds, LaNb7O19 and CeNb7O19, could be prepared and characterized. At temperatures about 900°C already decomposition of both compounds will be initiated, but at lower temperatures (800°C) no reaction between the binary components occured. Single crystals could be obtained by chemical transport reactions (T2 → T1; T2 = 800°C; T1 = 780°C). Chlorine for mineralization or as transport agent is absolutely indispensable for preparation. Single crystal investigations on LaNb7O19 (R = 4.4%; Rw = 4.19%) result in the trigonal space group P3. The cell dimensions are a = 6.2531(2) A; c = 20.0685(10) Å; Z = 2. The structure can be described as to be build up by layers of 8-coordinated La and 6-coordinated Nb, alternating with layers of edge-sharing pentagonal NbO7-bipyramids. Corresponding to the unusual sequence of layers the structure of LnNb7O19 (Ln = La,Ce) is the first example of a trigonal member of a family of structures, which has been described in detail by Jahnberg. The most examples are represented by tantalates, but only a few niobates related to these structures are known.  相似文献   

6.
Syntheses and Crystal Structures of New Alkali Metal Rare‐Earth Tellurides of the Compositions KLnTe2 (Ln = La, Pr, Nd, Gd), RbLnTe2 (Ln = Ce, Nd) and CsLnTe2 (Ln = Nd) Of the compounds ALnQ2 (A = Na, K, Rb, Cs; Ln = rare earth‐metal; Q = S, Se, Te) the crystal structures of the new tellurides KLaTe2, KPrTe2, KNdTe2, KGdTe2, RbCeTe2, RbNdTe2, and CsNdTe2 were determined by single‐crystal X‐ray analyses. They all crystallize in the α‐NaFeO2 type with space group R3¯m and three formula units in the unit cell. The lattice parameters are: KLaTe2: a = 466.63(3) pm, c = 2441.1(3) pm; KPrTe2: a = 459.73(2) pm, c = 2439.8(1) pm; KNdTe2: a = 457.83(3) pm, c = 2443.9(2) pm; KGdTe2: a = 449.71(2) pm, c = 2443.3(1) pm; RbCeTe2: a = 465.18(2) pm, c = 2533.6(2) pm; RbNdTe2: a = 459.80(3) pm, c = 2536.5(2) pm, and CsNdTe2: a = 461.42(3) pm, c = 2553.9(3) pm. Characteristics of the α‐NaFeO2 structure type as an ordered substitutional variant of the rock‐salt (NaCl) type are layers of corner‐sharing [(A+/Ln3+)(Te2—)6] octahedra with a layerwise alternating occupation by the cations A+ and Ln3+.  相似文献   

7.
Synthesis and Crystal Structure of Tetrakis(pentafluorophenylamino)silane Colourless single-crystals of Tetrakis(pentafluorophenylamino) silane were obtained from the reaction of SiCl4 with monolithiated pentafluoroaniline at low temperatures. The aminosilane has been characterized by various spectroscopic methods and its crystal structure has been determined by x-ray diffraction (for details see “Inhaltsübersicht”). Thermal condensation has not been achieved. However, reaction of silicon(IV)-chloride with pentafluoroaniline in the presence of triethylamine yielded the respective tricyclosilazane.  相似文献   

8.
Fluoroplatinates(IV) of the Lanthanides LnF[PtF6] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er) For the first time fluorides LnF[PtF6] (Ln = Pr, Sm, Gd, Tb, Dy, Ho, Er), all yellow have been obtained. From single crystal data they crystallize monoclinic, space group P21/n?C (No. 14), Z = 4, Pr: a = 1 125.77(19) pm, b = 559.04(7) pm, c = 910.27(17) pm, β = 107.29(1)°; Sm: a = 1 114.63(31) pm, b = 552.70(12) pm, c = 898.02(20) pm, β = 107.24(2)°; Gd: a = 1 112.12(15) pm, b = 551.22(7) pm, c = 891.99(11) pm, β = 107.09(1)°; Tb (Powder data): a = 1 108.88(20) pm, b = 552.71(9) pm, c = 889.56(16) pm, β = 107.30(1)°; Dy: a = 1 100.28(23) pm, b = 547.77(8) pm, c = 882.41(13) pm, β = 107.32(1); Ho: a = 1 099.11(16) pm, b = 546.16(7) pm, c = 879.45(15) pm, β = 107.34(1)°; Er: a = 1 095.10(16) pm, b = 544.82(10) pm, c = 874.85(14) pm, β = 107.37(1)°.  相似文献   

9.
The crystal structures of the complex sulfides SrLnCuS3 (Ln = Sm, Gd, Er and Lu) have been determined and refined using powder X‐ray diffraction. The crystals are found to be orthorhombic, with the structure type changing consecutively in the order BaLaCuS3 → Eu2CuS3 → KZrCuS3 as the Ln3+ ionic radius decreases in the order La/Pr → Sm/Gd → Er/Lu. Variations of the structure parameters along the series of compounds studied are analyzed, and an effect caused by crystallochemical contraction on the stabilization of the respective structure types is demonstrated.  相似文献   

10.
Thioureato Brigded Binuclear Complexes of the Lanthanides Synthesis and Crystal Structure of [{PhC(NPh)NC(S)NEt2}{Et2NC(S)NH}LnBr(thf)]2 (Ln = Gd, Sm) The reaction of potassium-N-(diethylaminothiocarbonyl)-N′-phenyl-benzamidinat with LnBr3 (Ln = Gd, Sm) leads to the formation of the binuclear complexes [{PhC(NPh)NC(S)NEt2}{Et2NC(S)N}LnBr(thf)]2} (Ln = Gd 1 , Sm 2 ). The two bridging thiureatoligands are probably built during the reaction of potassium with the starting ligand. Coordination by one N-(diethylaminothiocarbonyl)-N′-phenylbenzamidinato-ligand, one Br-ion and one THF-ligand leads to square antiprismatic coordination of the lanthanoids. The structures of both compounds were characterized by X-ray analysis ( 1 : P1 (Nr.2), Z = 1, a = 12,006(4) Å, b = 12,245(4) Å, c = 13,612(3) Å, α = 70,55(3)°, β = 68,21(3)°, γ = 81,31(3)° 2 : P1 (Nr.2), Z = 1, a = 11,803(3) Å, b = 12,344(5) Å, c = 12,797(8) Å, α = 103,07(5)°, β = 101,76(3)°, γ = 114,13(3)°)  相似文献   

11.
Synthesis and Crystal Structure of NaBi2AuO5 NaBi2AuO5 was obtained by hydrothermal reaction of ‘Bi2O5’, Au2O3 · 2H2O and saturated aqueous NaOH solution at temperatures from 300 to 600°C and oxygen pressure from 3 × 108 to 6 × 108 Pa for the first time. The crystal structure (P4 b2; a = 1 220.02(6) pm; b = 386.68(3) pm; Z = 4; Rw = 0.022) consists of bisphenoidic distorted AuO4 groups, which are stacked in c-direction. They are connected by square pyramidal BiO5 units. Sodium is occupying holes within the Au/Bi/O framework thus formed.  相似文献   

12.
13.
Polycrystalline boratotungstates of composition Ln3BWO9 (Ln = Pr, Nd, Sm, Gd, Tb, Dy) are prepared by solid-phase synthesis and structurally studied. The structures are refined using the Rietveld method for hexagonal space group P63 (Z = 2). The boratotungstate structures are frameworks. The rare-earth cations in the structure are coordinated by an array of nine oxygen atoms (three oxygen atoms from borato groups BO3 and six from WO6 polyhedra). The nature of the optical nonlinearity in the hexagonal boratotungstates Ln3BWO9 is a direct consequence of the acentricity of both the tungstate and the rare-earth polyhedra in the structure. Dimorphism is discovered in polycrystalline La3BWO9.  相似文献   

14.
Ln3UO6Cl3 (Ln=La, Pr, Nd) — The First Oxochlorouranates of the Rare Earths . The new compounds Ln3UO6Cl3 (Ln=La, Pr, Nd) were prepared by heating stoichiometric amounts of LnOCl/Ln2O3/U3O8 (7 : 1 : 1) (Ln=La, Nd) and PrOCl/Pr6O11/U3O8 (12 : 1 : 2) in silica ampoules (5 d, 1000°C, Ln=La; 9 d 800°C, Ln=Pr, Nd) in the presence of an excess of chlorine [p(Cl2, 25°C)=1 atm]. Single crystals were obtained by chemical transport reactions using chlorine [p(Cl2, 25°C)=1 atm] as transport agent [T2=1000°C→T1=900°C (Ln=La); T2=840°C→T1=780°C (Ln=Pr, Nd)]. Crystals of Ln3UO6Cl3 (Ln=La, Pr, Nd) were investigated by X-ray diffraction methods and La3UO6Cl3 additionally by high resolution electron microscopy. The compounds Ln3UO6Cl3 crystallize in the hexagonal spacegroup P63/m (No. 176) with Z=2 formula units per unit cell. Isotypical structure refinements resulted in R=3.04% respectively Rw=1.91% (Ln=La), R=4.72% respectively Rw=3.80% (Ln=Pr) and R=3.99% respectively Rw=2.49% (Ln=Nd). Uranium is coordinated with six oxygen atoms forming a trigonal prism. Lanthanide ions are 10-coordinated (6 oxygen atoms, 4 chlorine atoms).  相似文献   

15.
Synthesis, Crystal Structure and Thermal Behaviour of Cs1,5[Re3I3Cl7,5(H2O)1,5] Dark brown tetrahedra of Cs1,5[Re3I3Cl7,5(H2O)1,5] crystallize on slow cooling of a hot saturated solution of ReI3 and CsCl in conc. hydrochlorid acid. The crystal structure (cubic, P4 3m (No. 215), a = 1241.06(3)pm, Vm = 287.8(1) cm3mol?1, Z = 4, R = 0.067, Rw = 0.037) is built up from isolated building units [Re3I3Cl7,5(H2O)1,5]1,5? with statistical distribution of chloride ions and water molecules in the in plane, terminal positions. Consistent with the result based on the X-ray analysis, the IR-spectrum shows one band for the OH stretching frequencies of the water molecules coordinated to the Re3 triangle at 3240 cm?1. The anions are arranged in the fashion of a cubic closest packing with the cesium ions occupying all octahedral and one quarter of the tetrahedral interstices. Temperature-dependent Guinier-Simon photographs in connection with DTA/TG investigations reveal that Cs1,5[Re3I3Cl7,5(H2O)1,5] releases water at 190°C accompanied with a structural transition and the dehydration product decomposes at 370°C to Cs2ReCl6?xIx, Re3I3+yCl6?y and rhenium metal.  相似文献   

16.
A thermodynamic model of liquid was suggested and Ln-Ba (Ln = Gd, Pr, Nd, and Sm) phase diagrams were calculated on the basis of generalization of literature data on thermodynamic properties and phase equilibria in lanthanide-barium metallic systems. The interaction parameter of Gd1 ? x Ba x regular melt was estimated on the assumption of a proportionality between the particle-particle interaction energies of liquid lanthanide and liquid barium, on the one hand, and the lanthanide radius, on the other.  相似文献   

17.
Preparation, Crystal Structure, and IR-spectroscopic Investigation of Phosphorus Nitride Imide, HPN2 Pure and fine crystalline phosphorus nitride imide (HPN2) is obtained by heterogeneous ammonolysis of P3N5 with gaseous NH3 (T = 580°C, p = 30 bar, 6 d). X-ray powder diffraction data has been used to refine the crystal structure of HPN2 by the Rietveld full-profile technique (I4 2d; a = 461.82(2) pm, c = 702.04(3) pm; Z = 4; 41 reflections observed, 17° < 2Θ < 125°, CuKα1, germanium monochromator; R(wp) = 0.072, R(I,hkl) = 0.048). In the solid HPN2 contains a three-dimensional framework of corner-sharing PN4-tetrahedra (P N: 159.9(4) pm; P N P: 130.1(4)°. The hydrogen atoms are covalently bonded to half of the nitrogen atoms. The IR spectrum exhibits six vibrational modes v(N H): 3224; vas(PNP): 1330, 1223; vas(PNHP): 971, 901: δ(PNP): 531 cm−1).  相似文献   

18.
Structure and Thermal Degradation of Bis(1,3-diketonato)cobaltbisimidazoles The crystal structure of Co(bzac)2(HIm)2. 2MeOH ( I ) and Co(acac)2(HIm)2 ( II ) were determined by x-ray diffraction. II : triclinic, space group P1 , Z = 2, a = 746.3(1), b = 948.2(1), c = 1396.7(2)pm, α = 85.18(1)°, β = 88.96(1)°, γ = 80.72(1)°, R = 3.0% for a total of 2194 observed reflections. I : monoclinic, P21/c, Z = 2, a = 964.2(3), b = 864.5(2), c = 1769.8(4)pm, β = 98.87(2)°, R = 4.7% for a total of 967 observed reflections. In both compounds centrosymmetric molecules with two bidentate diketonato groups and two imidazole ligands in trans-position are present. The molecules of II are linked by N? H…?O-bridges within layers, while in the lattice of I by the interaction with methanol molecules N-H…?O-H…?O-bridges are formed. The nature of the H-bridges is the deciding factor for the first step of the thermal degradation of the complexes. The N-H…?O-bridges of II relieves the change of the acidic protons of the imidazole to the acetylacetonato ligands. Therefore in the first step acetylacetone is eliminated. No such bridges are present in the complex I . Therefore, in the first step, imidazole and methanol are removed. On heating in O-donor solvents the reaction of I is quite analogous, and this is the reason for the application of this complex as a latent initiator of the epoxide polymerisation.  相似文献   

19.
Rb3LnCl6 · 2 H2O (Ln = La? Nd): Preparation, Crystal Structure, and Thermal Behaviour The compounds Rb3LnCl6 · 2 H2O (Ln = La? Nd) were prepared from acetic acid as powders. The preparation from aqueous solutions does not yield the pure products because RbCl precipitates as first compound. The structure of Rb3LaCl6 · 2 H2O was determined by X-ray analysis of a single crystal obtained from aqueous solution. The compounds with Ln = La? Nd are isotypic. They crystallize hexagonally in the space group P63/m (Rb3LaCl6 · 2 H2O: a = 1 220.4(2) pm, c = 1 688.6(3) (pm) with Z = 6. Anionic trimeric units [Ln3Cl12(H2O)6]3? are stacked along the c-axis over the corners of the unit cell. In the stacking frequency the units are rotated by 60° with respect to each other around the c-axis. The coordination number (C. N.) of Ln3+ is 8, which is satisfied by four bridging and two terminal chloride ions and two water molecules. The coordination spheres of the three rubidium ions in the different atomic positions are composed differently, their C.N. are 9, 8(+1) and 6(+6). The thermal dehydration of the compounds occurs in one step. The hydrates decompose at ca. 100°C to form the anhydrous compounds Rb2LnCl5 und RbCl since the anhydrous chlorides Rb3LnCl6 are thermodynamically stable above ca. 400°C only.  相似文献   

20.
Synthesis and Crystal Structure of Calcium Imide, CaNH Single-crystals of calcium imide were obtained for the first time by the reaction of a mixture of calcium amide with sodium amide at 850°C in an autoclave for salt melts. After cooling the autoclave to room temperature the crystals are embedded in solid Na which was extracted by liquid ammonia. The structure of calcium imide was determined from single-crystal diffractometer data: space group Fm3 m, Z = 4, a = 5.143(1) Å, R/Rw = 0.032/0.028 mit N(F º 2 ? 3σ(F º 2 )) = 26, N(Var.) = 5. Ca and N atoms are arranged in the motif of the NaCl structure type. The hydrogen atoms of the imide groups are disordered within the Ca octahedra, and they occupy a six fold split position.  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