Kristallstrukturen zweier Modifikationen von In5Mo18O28 und deren Zwillingsbildung

Crystal Structures of Two Forms of In₅Mo₁₈O₂₈ and Twinning In₅Mo₁₈O₂₈ is prepared from In, Mo and MoO₂ at 1 150°C in an evacuated quartz glass ampoule. X-ray investigations on single crystals show monoclinic symmetry (a = 1 323.13(9), b = 951.88(10), c = 989.48(8) pm, β = 100.976(4)°, space group P 2₁/c (No. 14)) for form 1 . The second form ( 2 ) crystallizes in the orthorhombic system (space group Pmcn (No. 62), a = 2 596.6(5), b = 952.0(2), c = 989.6(2) pm). Twinning and charge balances are discussed.     

Das System Gd/Co/B: Darstellung und röntgenographische Charakterisierung von GdCo4B,Gd3Co11B4, GdCoB4 und GdCo12B6

The System Gd/Co/B: Preparation and Characterization by X‐ray Diffraction of GdCo₄B, Gd₃Co₁₁B₄, GdCoB₄, and GdCo₁₂B₆ The compounds GdCo₄B, Gd₃Co₁₁B₄, GdCoB₄, and GdCo₁₂B₆ were characterized by X‐ray investigations of single crystals. GdCo₄B (P 6/mmm, a = 505.9(1) pm, c = 690.1(1) pm) crystallizes with the CeCo₄B structure type; Gd₃Co₁₁B₄ (P 6/mmm, a = 508.7(1) pm, c = 982.9(9) pm) with the Ce₃Co₁₁B₄ stucture type; GdCo₁₂B₆ ( , a = 949.5(1) pm, c = 747.4(1) pm) with the SrNi₁₂B₆ structure type and GdCoB₄ (P bam, a = 591.3(9) pm, b = 1145.1(6) pm, c = 346.2(3) pm) with the YbCoB₄ structure type.     

Über die Kristallstruktur von In3Mo11O17 sowie über physikalische Eigenschaften oligomerer Oxomolybdate

On the Crystal Structure of In₃Mo₁₁O₁₇ and the Physical Properties of Oligomeric Oxomolybdates In₃Mo₁₁O₁₇ is characterized by its molybdate framework Mo₂₂O₃₄^8? belonging to the general series Mo_4n+2O_6n+4^x? (with n = 5). The phase grows in star-like aggregates and crystallizes within the orthorhombic system (a = 988.0(2) pm, b = 951.2(2) pm, c = 3 176.7(4) pm). There are oligomeric clusters built from five trans edge-sharing Mo₆ octahedra, surrounded by O atoms over all empty edges according to the Aufbau principle Mo₂₂OOO. In the remaining structural channel one finds an In₆⁸⁺ polycation which is geometrically equivalent with the one of In₁₁Mo₄₀O₆₂. The Mo—O and Mo—Mo distances within the cluster are the same like in In₁₁Mo₄₀O₆₂, too, but there are shorter inter cluster distances (306 pm) in In₃Mo₁₁O₁₇. Disorder in the structure may be understood in terms of the presence of constitutional isomers. While the electrical resistivity of PbMo₅O₈ resembles the one of a strongly disturbed metal (with a local minimum around 120 K), the temperature characteristic of Tl_0.8Sn_0.6Mo₇O₁₁ is typical for a semiconductor. Oxomolybdates with even longer oligomers like In₁₁Mo₄₀O₆₂ and In₃Mo₁₁O₁₇ show metallic conductivity. This course corresponds with the sizes of the clusters and their electronic intercoupling which can be estimated from the specific lengths of the inter cluster distances. The effective magnetic moment grows with increasing cluster length from 0.97 μ_B (PbMo₅O₈) to 1.40 μ_B (In₁₁Mo₄₀O₆₂) per cluster (exception: In₃Mo₁₁O₁₂), and so does the contribution of the temperature-independent paramagnetism (from 890 to 2191 × 10^?6$ \frac{{{\rm emu}}}{{{\rm mol}}} $ per cluster). Thus, a single condensed octahedron carries roughly 440 × 10^?6$ \frac{{{\rm emu}}}{{{\rm mol}}} $ as a temperature-independent paramagnetism, similar to the M₆X₁₇ halide clusters. In₁₁Mo₄₀O₆₂ shows an interesting change in the temperature dependence of its magnetic suszeptibility.     

6-氯-N,N-二甲基嘧啶-4-胺的晶体结构研究

X-射线单晶衍射结果表明,所合成的6-氯-N,N-二甲基嘧啶-4-胺的晶体结构属正交晶系,Pbca空间群,晶胞参数为a=10.922(2),b=7.386(3),c=17.861(6)。由于在其晶格内存在着潜在的C—H…N和C—H…Cl两类分子间弱相互作用力,形成了二维网络结构,化合物变得更加稳定。     

Synthese und Kristallstruktur von PbMo5O8; ein reduziertes Oxomolybdat mit Mo10O28-Oktaederdoppeln

Synthesis and Crystal Structure of PbMo₅O₈; a reduced Oxomolybdate with Mo₁₀O₂₈ Double Octahedra The crystal structure of the new phase PbMo₅O₈ contains oligometric Mo clusters which consist of two edge-sharing Mo₆ octahedra connected according to Mo₁₀OOO. The compound is isotypic with LaMo₅O₈. Isolated, divalent Pb atoms are located in the “channels” of the monoclinic structure (a = 999.3(2) pm, b = 924.7(1) pm, c = 753.6(2) pm, β = 109.39(2)°, P2₁/a. Compared to the compound In ₁₁Mo₄₀O₆₂ the Mo? O distances (average 206 pm) and the Mo? Mo distances within the octahedral units (average 275 pm) are slightly decreased by 1 and 4 pm, respectively. The very short Mo? Mo distances (278 pm) between the cluster units which are not observed in In₁₁Mo₄₀O₆₂ (320 pm) are due to excess electrons in these inter-cluster bonds which would otherwise occupy antibonding cluster states.     

Synthesis,Crystal Structure and Thermal Behavior of Gadolinium Dicyanamide Dihydrate Gd[N(CN)2]3 · 2 H2O

Gadolinium dicyanamide dihydrate Gd[N(CN)₂]₃ · 2 H₂O was prepared by ion exchange in aqueous solution followed by evaporation of the solvent at room temperature. Gd[N(CN)₂]₃ · 2 H₂O was characterized by single‐crystal structure analysis, FTIR spectroscopy and DSC analysis. In the crystal there are three crystallographically independent [N(CN)₂]^? ions and Gd³⁺ which are coordinated by six N atoms from six different [N(CN)₂]^? ions and two O atoms from two water molecules forming an irregular quadratic antiprism. Four H bonds have been identified in the structure of Gd[N(CN)₂]₃ · 2 H₂O, two of them running to terminal N atoms and two to the bridging N atoms of dicyanamide ions (Gd[N(CN)₂]₃ · 2 H₂O: P2₁/n (no. 14), a = 7.4845(15) Å, b = 11.529(2) Å, c = 13.941(3) Å, β = 93.98(3)°, Z = 4, 1948 reflections, 175 parameters, R1 = 0.0493). The DSC analysis indicates that Gd[N(CN)₂]₃ · 2 H₂O looses the crystal water at temperatures around 130 – 140 °C forming anhydrous Gd[N(CN)₂]₃, the structure of which has been refined by the Rietveld method based on X‐ray powder diffraction data. Gd[N(CN)₂]₃ was found to be isotypic with Ln[N(CN)₂]₃ (Ln = La, Ce, Pr, Nd, Sm and Eu) which previously have been described in the literature.     

The New Carbodiimide Li2Gd2Sr(CN2)5 Having a Crystal Structure Related to That of Gd2(CN2)3

The new carbodiimide compounds Li₂RE₂Sr(CN₂)₅ (RE = Sm, Gd, Eu, Tb) were prepared by a straight forward solid state metathesis reaction of REF₃, SrF₂, and Li₂(CN₂) at around 600 °C. The crystal structure of Li₂Gd₂Sr(CN₂)₅ was solved based on X‐ray single‐crystal diffraction data. Corresponding Li₂RE₂Sr(CN₂)₅ compounds were analyzed by isotypic indexing of their powder patterns. The crystal structure of Li₂Gd₂Sr(CN₂)₅ can be well related to that of Gd₂(CN₂)₃, because both structures are based on layered structures composed of close packed layers of [N=C=N]^2– sticks, alternating with layers of metal ions. The crystal structure of Li₂Gd₂Sr(CN₂)₅ can be considered to contain an ABC layer sequence of [N = C=N]^2– layers with the interlayer voids being occupied by (three) distinct types of cations.     

Ln2(ClO4)2(H2I2O10) · 8H2O (Ln = Sm,Gd), a Lanthanide Perchlorate Mesodiperiodate forming a Novel Layer Structure

By slow evaporation of solutions containing Ln(ClO₄)₃ (Ln = Sm, Gd), H₅IO₆ and an excess of HClO₄, crystals of the title compounds could be obtained. Their structures were determined by single‐crystal X‐ray diffraction. The compounds crystallize in the monoclinic crystal system, space group P2₁/c. They contain Ln³⁺ ions, which are coordinated by [H₂I₂O₁₀]^4— anions forming two‐dimensional, cationic networks. These are separated by perchlorate ions, forming a layered structure.     

Crystal Structure of LiClO4

Single crystals of LiClO₄ were obtained during attempts to prepare lithium containing rare earth perchlorates from a lithium perchlorate melt. In the crystal structure of LiClO₄ (ortho‐rhombic, Pnma, Z =4, a = 865.7(1), b = 691.29(9) pm, c = 483.23(6), R_all = 0.0273) the Li⁺ ions are in distorted octahedral coordination of oxygen atoms. The octahedra are linked via common edges to chains according to ¹[LiO_2/1O_4/2] which run in the [010] direction. The perchlorate ions are almost ideal tetrahedra.     

Synthesis,Crystal Structure and Magnetic Behaviour of the new Tetrameric Gadolinium Carboxylate [Gd4(OH)4(CF3COO)8(H2O)4] · 2.5 H2O

The novel tetrameric gadolinium(III) compound [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was synthesized and structurally characterized by X‐ray crystallography. The Gd³⁺ ions are bridged by hydroxide ions and carboxylate groups to tetramers with Gd³⁺‐Gd³⁺ distances between 384.2(2) and 388.1(2) pm. The compound crystallizes in the monoclinic space group C2/c (Z = 4). The magnetic behaviour of [Gd₄(OH)₄(CF₃COO)₈(H₂O)₄] · 2.5 H₂O was investigated in the temperature range of 2 to 300 K. The magnetic data of this compound indicate antiferromagnetic interactions (J_ex = ?0.0197 cm^?1).     

三乙四胺六乙酸钆单核配合物的合成及晶体结构

在水溶液中合成了三乙四胺六乙酸(H₆ttha)钆单核配合物(NH₄)₂[Gd(Httha)]·6H₂O,获得了单晶,并测定了其结构.晶体属单斜晶系,P2₁/c空间群.晶胞参数a=1.0400(4)nm,b=1.2761(4)nm,c=2.3132(4)nm,β=90.89(3)°,V=3.070(2)nm³,Z=4,D_c=1.709g/cm³.R₁=0.0394,F(000)=1612.配合物是单核分子,每个钆离子与来自同一个三乙四胺六乙酸的4个氮原子和5个羧基氧原子配位,配位数为9,形成单帽四方反棱柱型配位多面体.     

[C6N2H18]2[Mo5O15(HPO4)2]·H2O的水热合成与结构表征

通过水热法合成了一个新化合物[C6N2H18]2[Mo5O15(HPO4)2]·H2O,并通过IR光谱、ICP、元素分析、差热与热重分析和X射线单晶衍射分析等手段进行了表征.结果表明,晶体属三方晶系,P3(2)21空间群,a=1.1231(1)nm,c=2.2802(5)nm,V=2.4911(7)nm3,Dx=2.835Mg/m3,Z=6,最后的一致性因子R=0.0227,wR=0.0675.阴离子中Mo5O15构成一环状结构,2个HPO4一个连在环的下方,一个连在环的上方,形成类似于“飞碟”状的结构,阳离子为2个质子化的四甲基乙二胺.     

Synthesis and Crystal Structure of CuIIMoIVF6 and CrIINbIVF6 (LT Form)

The fluorides CuMoF₆ and CrNbF₆ are triclinic, isostructural with CuSnF₆. Their crystal structures were solved in the space group P1, by the Rietveld method using the data of their X-ray powder patterns. Both crystal structures can be described as a three-dimensional framework of alternating 6 corner-sharing [M^IIF₆] and [M′^IVF₆] octahedra (M^II = Cr, Cu; M′^IV = Nb, Mo) with ferrodistortive Jahn-Teller ordering.     

Crystal Structure of Rubidium Tetraiodothallate(III) Dihydrate,RbTlI4·2H2O

The crystal structure of RbTlI₄·2H₂O (cubic, , Nr. 226, Z = 24, a = 1993.5(2) pm, 327 unique reflections with I_o > 2σ(I_o), R₁ = 0.0305, wR₂ = 0.0702, GooF = 1.1199, T = 298(2) K) is characterized by an ReO₃ analogous arrangement of rubidium centered [TlI₄] tetrahedra. The cuboctahedral cavities of this structure are filled with crystal water molecules and additional disordered rubidium cations.     

The Crystal Structure of Ni21Sn2P6

During an investigation of the phase equilibria in the ternary system Ni/P/Sn, the existence of a new phase Ni₂₁Sn₂P₆ with a composition close to the known Ni₁₀P₃Sn phase was found. The crystal structure of the new phase was determined using single crystal X‐ray diffraction. The structure was solved employing Patterson and Difference Fourier Analysis. Ni₂₁P₆Sn₂ (space group , a = 1112.2 pm) crystallizes in an ordered variant of the C₆Cr₂₃ structure common to many carbides, borides and phosphides. The relation between Ni₂₁Sn₂P₆ and other C₆Cr₂₃ type phases and to Ni₁₀P₃Sn was established.     

Crystal Structure Analysis by Neutron Diffraction II

This second part of the article “Crystal Structure Analysis by Neutron Diffraction” deals with the diffraction of neutrons by magnetically ordered crystals. Neutron diffraction is at present the only reliable method for the determination of the magnitude, direction, and spatial distribution of magnetic moments in crystalline substances. Since the magnetic moments are essentially due to the unpaired electrons, the distribution of these electrons in the crystal can be measured in this way.     

Kristallstruktur von BaGdCl5

Crystal Structure of BaGdCl₅ Colourless single crystals of BaGdCl₅ are obtained from a 1 : 2 molar mixture of BaCl₂ and GdCl₃. It crystallizes with the monoclinic space group C2/c with a = 552.1(2), b = 1925.7(5), c = 687.4(2) pm, β = 93.25(4)° in a new structure. Ba²⁺ and Gd³⁺ have coordination numbers of 8 + 2 and 8, respectively.