Half Antiperovskites: IV. Crystallographic and Electronic Structure Investigations on A2Rh3S2 (A = In,Sn, Tl,Pb, Bi)

The crystal and electronic structures of ordered half antiperovskites A₂Rh₃S₂ = ARh_3/2S (A = In, Sn, Tl, Pb, Bi) are investigated. From powder and single crystal data superstructures, rhodium site ordering, trends in bonding and coordination are analysed with respect to the A site atom. Comparisons address isotypic and isoelectronic relations to monoclinic parkerite (Bi₂Ni₃S₂) type superconductors, the trigonal half‐metal ferromagnet Sn₂Co₃S₂, and rhodium‐containing antiperovskites. Local structure and bonding is analysed with respect to the ordered occupation of half of S₂A₄ sites (= perovskite oxygen sites) and interlinking to 2D networks [Rh₃S₂]_∞^δ– by face‐, edge‐ and corner‐sharing. The theoretical part includes DFT band structure and ELF calculations, systematic comparisons to rhodium and antiperovskites, as well as spin‐polarised calculations on Sn₂Rh₃S₂ and Pb₂Rh₃S₂.     

Structure, ordering, and bonding of half antiperovskites: PbNi3/2S and BiPd3/2S

In a model study the crystal structures of shandite (Pb₂Ni₃S₂), parkerite (Bi₂Ni₃S₂) and their Pd homologues are investigated in terms of ordered half antiperovskites AM_3/2S (A = Pb, Bi; M = Ni, Pd). This addresses fundamental questions on the structural relations, ordering and chemical bonding. From crystal structure investigations a new cubic parkerite variant is presented for Bi₂Pd₃S₂ that fits in an ordering model equivalently to shandite and parkerite. Type–antitype relations to ordered oxygen deficit perovskites are presented. With the relation to the superconductor Ni₃MgC a model is deduced that provides the complete crystal structure and symmetry in terms of the Ni and Pd ordering in antiperovskite superstructures. Therein a systematic ab initio investigation on the relative stability of shandite and parkerite structures is carried out for the first time. From the DFT modelling results the preferences of the ordering variants and the distinct differences in the atomic coordination spheres are discussed. The bonding in the systems is investigated by site projected density of states and covalent bond energy calculations.     

Die trikline Kristallstruktur von Ag2Bi2S3Cl2: Pseudosymmetrie und Zwillingsbildung

Ruby‐red crystals of Ag₂Bi₂S₃Cl₂ were synthesized from AgCl and Bi₂S₃ by cooling a melt from 770 K to room temperature. X‐ray diffraction on powders and single‐crystals revealed a triclinic crystal structure with special lattice constants (P &1macr; (No. 2), a = 1085.0(2), b = 717.2(1), c = 1137.6(1) pm, α = 89.80(1)?, β = 74.80(1)?, γ = 87.81(1)?). In the structure [Bi^IIIS₃Cl₄] polyhedra form 2[BiS_3/2Cl_4/4]^‐ double‐layers by sharing common faces and edges. The silver(I) cations between the layers are coordinated either octahedrally by sulfide ions or tetrahedrally by sulfide and chloride ions. The deviations from the monoclinic space group P 1 2₁/c 1 are small and induce twinning along [010]. Further pseudosymmetry is based on the stacking of layer packages with the symmetry of the layer group P (2/c) 2₁/c 2/b.     

Synthese und Kristallstruktur von Bi2ErO4I

Synthesis and Crystal Structure of Bi₂ErO₄I Bi₂ErO₄I was prepared by solid‐state reaction of stoichiometric mixture of BiOI, Bi₂O₃ and Er₂O₃. Bi₂ErO₄I is a new compound and the first bismuth rare earth oxide iodide. The crystal structure was determined by the Rietveldmethod (P4/mmm, a = 3,8896(6) Å, c = 9,554(2) Å, Z = 1). In this structure [M₃O₄]⁺‐layers are interleaved by single I^–‐layers. Er and Bi atoms of Bi₂ErO₄I are 8‐coordinated. The structure can be derived from the LiBi₃O₄Cl₂‐structure type.     

Synthesis,Spectral, Thermal Studies of Co(II), Ni(II), Cu(II) and Zn(II)‐arginato Complexes. Crystal Structure of Monoaquabis(arginato‐κO,κN)copper(II). [Cu(arg)2(H2O)].NaNO3

Transition metal complexes of arginine (using Co(II), Ni(II), Cu(II) and Zn(II) cations separately) were synthesized and characterized by FTIR, TG/DTA‐DrTG, UV‐Vis spectroscopy and elemental analysis methods. Cu(II)‐Arg complex crystals was found suitable for x‐ray diffraction studies. It was contained, one mole Cu^II and Na⁺ ions, two arginate ligands, one coordinated aqua ligand and one solvent NO₃^? group in the asymmetric unit. The principle coordination sites of metal atom have been occupied by two N atoms of arginate ligands, two carboxylate O atoms, while the apical site was occupied by one O atom for Cu^II cation and two O atoms for Co^II, Ni^II, Zn^II atoms of aqua ligands. Although Cu^II ion adopts a square pyramidal geometry of the structure. Co^II, Ni^II, Zn^II cations have octahedral due to coordination number of these metals. Neighbouring chains were linked together to form a three‐dimensional network via hydrogen‐bonding between coordinated water molecule, amino atoms and O atoms of the bridging carboxylate groups. Cu^II complex was crystallized in the monoclinic space group P2₁, a = 8.4407(5) Å, b = 12.0976(5) Å, c = 10.2448(6) Å, V = 1041.03(10) ų, Z = 2. Structures of the other metal complexes were similar to CuII complex, because of their spectroscopic studies have in agreement with each other. Copper complex has shown DNA like helix chain structure. Lastly, anti‐bacterial, anti‐microbial and anti‐fungal biological activities of complexes were investigated.     

Darstellung und Struktur einer Hochdruckmodifikation des Bariumthioplatinats(II), BaPt2S3

Synthesis and Structure of a High‐pressure Modification of the Bariumthioplatinate(II), BaPt₂S₃ BaPt₂S₃, obtained via the precursor BaPt(CN)₄·2H₂O, was found to undergo a high‐pressure phase transformation at 10 kbar and 600 °C. The structure of the high‐pressure modification was solved with single crystal data. (Space group P4₁2₁2, Z = 12, a = 11.058(1) Å, c = 13.125(1) Å). Two planar [PtS₄]‐units are linked by one common side forming [Pt₂S₆]‐groups, which built up a three‐dimensional framework. The barium ions are coordinated by seven sulfur neighbours.     

Beiträge zur Kristallchemie der Urantelluride. II. Die Kristallstruktur des Diuranpentatellurids U2Te5

Contributions to the Crystal Chemistry of Uranium Tellurides. II. The Crystal Structure of Diuranium Pentatelluride U₂Te₅ Via chemical transport reactions with TeBr₄ as transporting agent single crystals of the title compound up to a size of 5 mm were available from the elements. The analysis by atomic emission spectrometry gave UTe_2.52(4). By X-ray single crystal structure analysis we found that U₂Te₅ crystallizes monoclinic (space group C2/m, Z = 4) with a = 3443.3(5) pm, b = 418.65(3) pm, c = 607.97(6) pm and β = 95.35(1)º in a new structure type. The layer structure is built up by bicapped trigonal prisms, one half as isolated building units, the other connected via faces as fourfold capped biprisms. A structural relationship of diuranium pentatelluride to the adjacent phases in the phase diagram U? Te can be expressed by the formulation as UTe₂ · UTe₃.     

Darstellung und Kristallstruktur von Rb2Ni3Se4

Preparation and Crystal Structure of Rb₂Ni₃Se₄ The compound Rb₂Ni₃Se₄ was synthesized by heating a mixture of rubidium carbonate, nickel and selenium at 850°C in an atmosphere of hydrogen. The compound has a golden lustre and crystallizes with the K₂Pd₃S₄-type structure; a = 10.555(3) Å, b = 27.588(6) Å, c = 6.031(6) Å, Z = 8, Fddd (No. 70). The structure can be described as a stacking of layers of the composition Rb₂Ni₃Se₄ with a stacking sequence abcd. The electrostatic part of lattice energy (MAPLE) will be discussed for compounds of the compositions A₂M₃X₄ (A K, Rb, Cs; M Ni, Pd, Pt and X S, Se).     

Synthese und Kristallstruktur von K2Mn3S4

Synthesis and Crystal Structure of K₂Mn₃S₄ Single crystals of K₂Mn₃S₄ have been prepared by a fusion reaction of potassium carbonate with manganese in a stream of hydrogen sulfide at 900 °C. K₂Mn₃S₄ crystallizes in a new monoclinic layered structure type (P2/c, a = 7.244(2) Å, b = 5.822(1) Å, c = 11.018(5) Å, β = 112.33(3)°, Z = 2) which can be described as a stacking variant of the orthorhombic Cs₂Mn₃S₄ structure type. Measurements of the magnetic susceptibilities show antiferro‐magnetic interactions.     

The role of Mn in the electronic structure of Ba3Ti2MnO9

The energy loss near edge structure (ELNES) of the O-K, Ti-L₂₃ and Mn-L₂₃ edges have been recorded in hexagonal Ba₃Ti₂MnO₉ with an energy resolution of 0.10-0.20 eV using a monochromator on a commercial transmission electron microscope (TEM) and compared with a tetragonal BaTiO₃ reference sample. The formal valency and symmetry of Mn have been determined using atomic multiplets calculations and its effect on the electronic structure of BaTiO₃ has been interpreted through a molecular-orbital model.     

Kristallstruktur des Zinkamids Zn[N(SiMe3)2]2

Crystal Structure of the Zinc Amide Zn[N(SiMe₃)₂]₂ X‐ray quality crystals of Zn[N(SiMe₃)₂]₂ (monoclinic, P2₁/c) are obtained by sublimation of the zinc amide Zn[N(SiMe₃)₂]₂ at —30 °C in vacuo (300 torr). According to the result of the X‐ray structural analysis, Zn[N(SiMe₃)₂]₂ contains an almost linear N‐Zn‐N unit with two short N‐Zn bonds.     

重费米子化合物LiV2 O4电子结构的第一性原理研究

用第一性原理的FP-LMTO能带计算方法研究了重费米子化合物LiV2O4的电子结构.结果表明:费米面附近的导带是由V原子的3d电子形成的宽度为2.5eV的窄能带,是3d态在立方晶体场中具有t2g对称性的子带;它与O的2p轨道构成的能带有近1.9eV的能隙.计算得出的费米能处电子态密度和线性电子比热系数分别是11.1 states/eV f.u.和26.7 mJ/molK2.费米面处的能带色散具有电子型和空穴型两种,呈现出一种复杂的费米面结构.LSDA以及LDA+GGA计算表明, LiV2O4有一个磁矩为每个钒原子1.13μB,总能比LDA基态低约148 meV/f.u.的铁磁性基态.由目前的能带结构计算的结果无法确定这一类Kondo体系的局域磁矩的来源,表明这一化合物中的重费米子行为可能有别于在含有4f和5f稀土的重费米子合金中观察到的局域磁矩与传导电子的交换作用机制,其中存在量子相变的可能.     

Darstellung,Kristallstruktur und Eigenschaften des Kupfer(II)‐Indium(III)‐Orthophosphats Cu3In2[PO4]4

Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXIV. Preparation, Crystal Structure, and Properties of Copper(II) Indium(III) Orthophosphate Cu₃In₂[PO₄]₄ Crystals of Cu₃In₂[PO₄]₄ were grown by chemical vapour transport (temperature gradient 1273 K → 1173 K) using chlorine as transport agent. The mixed metal phosphate forms a new structure type (P2₁/c, Z = 2, a = 8.9067(6), b = 8.8271(5), c = 7.8815(5) Å, β = 108.393(5)°, 13 atoms in asymmetric unit, 2549 unique reflections with F_o > 4σ, 116 variables, R(F²) = 0.065). The crystal structure shows a hexagonal closest packing of [PO₄]^3– tetrahedra. Close‐packed layers parallel (1 0 –1) are stacked according to the sequence A, B, A′, B′, A. The octahedral interstices in this packing are completely occupied by two In³⁺, one (Cu1)²⁺ and a “dumb bell” (Cu2)₂⁴⁺. In the latter case four of the six phosphate groups that belong to this octahedral void act as bi‐dentate ligands, thus forming dimers [(Cu2)₂O₁₀] with d_Cu–Cu = 3.032 Å. Cu₃In₂[PO₄]₄ is paramagnetic (μ_eff = 1.89 μ_B, θ_P = –16.9 K). The infrared and UV/Vis reflectance spectra are reported. The observed d‐electron levels of the Cu²⁺ cations agree well with those obtained from angular overlap calculations.     

La4N2S3: Ein neues Nitridsulfid des Lanthans mit beispielloser Kristallstruktur

La₄N₂S₃: A New Nitride Sulfide of Lanthanum with Unprecedented Crystal Structure The oxidation of lanthanum powder with sulfur and cesium azide (CsN₃) in the presence of lanthanum tribromide (LaBr₃) yields lanthanum nitride sulfide with the composition La₄N₂S₃ when appropriate molar ratios of the reactants are used. Additional cesium bromide (CsBr) as a flux secures fast reactions (7 d) at 900 °C in evacuated silica tubes as well as the formation of almost black single crystals. The orthorhombic crystal structure (Pnnm, Z = 2) was determined from single crystal X‐ray diffraction data (a = 641.98(4), b = 1581.42(9), c = 409.87(3) pm). Two crystallographically different La³⁺ cations are present, La1 resides in sixfold coordination of two N^3? and four S^2? anions forming a trigonal prism and La2 is coordinated by two N^3? and five S^2? in the shape of a monocapped trigonal prism. However, the main feature of the crystal structure comprises N^3?‐centred (La³⁺)₄ tetrahedra which arrange as pairs [N₂La₆]¹²⁺ of edge‐shared [NLa₄]⁹⁺ units and which are further connected via four vertices to form double chains . They get bundled along [001] like a hexagonal rod packing and are held together by two crystallographically different S^2? anions. Further motifs for the connectivity of [NM₄]⁹⁺ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare‐earth elements (M = Sc, Y, La; Ce – Lu) with ratios of N : M = 1 : 2 are presented and discussed for comparison.     

Die Synthese und Kristallstruktur von K2UTe3

The Synthesis and Crystal Structure of K₂UTe₃ Syntheses of K₂UTe₃ were performed via polytelluride fluxes from K₂Te₃ and metallic uranium in the molar ratio 2 : 1 at 600 to 800 °C. Well-formed crystals were isolated by washing the reguli with liquid ammonia. One-phase powder samples of K₂UTe₃ are also available by reactions of stoichiometric mixtures of K₂Te₃ and uranium. K₂Te₃ was prepared in liquid ammonia from the elements using a glass apparatus specially designed for the synthesis of alkali metal chalcogenides. By x-ray structure analyses of single crystals we found K₂UTe₃ to crystallize monoclinic (space group C2/m, Z = 4) with the lattice parameters a = 800.41(3) pm, b = 1387.67(5) pm, c = 851.63(4) pm and β = 108.495(3)°. The crystal structure of the compound may be regarded as a stuffed AlCl₃-type structure. The existence of an analogous compound Rb₂UTe₃ crystallizing isotypically to K₂UTe₃ has been shown by x-ray powder investigations.     

钒硫团簇V2S2+、V3S4+的结构和稳定性

用ab initio分子轨道方法(RHF,UHF)和密度泛函(DFT)方法研究了团簇V2S2+、V3S4+的各种可能的几何构型和电子结构,所得理论计算能较好地解释有关实验结果.     

Synthesis,Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H2O)2(MoO4)2·H3O,NaCo2(MoO4)2(H3O2)and Mn2(MoO4)3·2H3O

Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray...     

Co(II), Ni(II) and Cu(II) complexes of new [1+1] and [2+2] macrocyclic ligands derived from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and cis-1,2-diaminocyclohexane

Two new macrocyclic ligands, L¹ (14-membered N₂O₂) and L² (28-membered N₄O₄) from [1+1] and [2+2] condensation, respectively, have been obtained in a one-pot synthesis starting from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and cis-1,2-diaminocyclohexane.