Partial Cu occupancy in uranium copper diantimonide,UCu0.60(4)Sb2

The title compound, UCu_0.60(4)Sb₂, crystallizes in the tetragonal space group P4/nmm. The U atom and one independent Sb atom have 4mm site symmetry, whereas the Cu atom and the other Sb atom have 2m site symmetry. Zigzag USb sheets stack perpendicular to the c axis. These sheets are separated by square‐planar nets of Sb atoms and Cu atoms. The length of the a axis for UCu_xSb₂ is invariant to x, whereas there is a linear relationship between Cu occupancy and the length of the c axis (following Vegard's Law) that holds for x between 0 and 1. This is explained in terms of the crystal structure.     

Präparation und Kristallstrukturanalyse von Ca(N3)2(C5H5N)2

Diazido-dipyridine-calcium was prepared by the reaction of Ca(N₃)₂ with pyridine. The crystals are tetragonal, space group I 2 m (121),N=2,a=699.7 (1),c=1 450.6 (5) pm. The crystal structure was determined by single crystal X-ray diffraction, 415 independent observed Mo-K-counter reflexions,R=0.049. The calcium atoms are sixcoordinated to four nitrogen atoms of azide groups and to two nitrogen atoms of pyridine. The coordination polyhedra are tetragonal bipyramids which are linked together by four azide groups to form sheets of composition Ca(N₃)₂. The pyridine rings are directed perpendicular to the sheets.

     

Das Zintl-Konzept als Syntheseprinzip: Darstellung und Kristallstrukturen von K2Ba3Sb4 und KBa4Sb3O

Starting from the Zintl-Concept: Syntheses and Crystal Structures of K₂Ba₃Sb₄ and KBa₄Sb₃O The black, metallic lustrous, air sensitive compounds K₂Ba₃Sb₄ and KBa₄Sb₃O were prepared from melts of mixtures of the elements, in case of KBa₄Sb₃O with a stoichiometric amount of Sb₂O₃. K₂Ba₃Sb₄ crystallizes in the orthorhombic system, space group Pnma (a = 870.5(1) pm, b = 1770.2(2) pm, c = 923.6(1) pm, Z = 4) and is the first Sb compound with only [Sb₂]^4– dumbbells in the anionic partial structure. The compound KBa₄Sb₃O crystallizes in the tetragonal system, space group I4/mcm (a = 882.4(1) pm, c = 1659.4(2) pm, Z = 4). In this structure antimony forms [Sb₂]^4–-dumbbells and isolated ions Sb^3–. Each antimony ion of the dumbbells – in K₂Ba₃Sb₄ as well as in KBa₄Sb₃O – is coordinated in form of a bicapped skew trigonal prism. The isolated Sb^3– ions in KBa₄Sb₃O center bicapped tetragonal antiprisms, the O^2– ions occupy tetrahedral voids.     

Darstellung und Kristallstruktur von CsSb2Se4

Preparation and Crystal Structure of CsSb₂Se₄ CsSb₂Se₄ was prepared by hydrothermal reaction of Cs₂CO₃ with Sb₂Se₃ at a temperature of 115°C. An X-ray structural analysis demonstrated that the compound contains polyselenoantimonate(III) anions (Sb₂Se₄^?)_n, which display both (Sb)Se? Sb and (Sb)Se? Se(Sb) bridges. A ψ-tetrahedral coordination is observed for one of the independent Sb atoms, a ψ-trigonal bipyramidal coordination for the other. The Sb? Se polyhedra are linked through joint corners and edges and in addition via direct Se? Se bonds into sheets.     

Methoxostibane. Struktur und Schwingungsspektren

Methoxostibanes. Structure and Vibrational Spectra The crystal and molecular structure of Sb(OMe)₃ ( 1 ) was determined by X-ray analysis. 1 forms layers in which the Sb atoms are coordinated by 6 O atoms. The halogenomethoxostibanes SbCl(OMe)₂ ( 2 ), SbCl₂(OMe) ( 3 ), SbBr(OMe)₂ ( 4 ), SbBr₂(OMe) ( 5 ), and SbI(OMe)₂ ( 6 ), which were partially prepared for the first time, as well as 1 were examinated by vibrational spectroscopy. The spectra were discussed in view of the structure in the solid state. 2, 4 , and 6 posses a structure similar to that of 1 with Sb₂O₂ and Sb₂Cl₂ ring systems. The coordination number of Sb is 6. In 3 and 5 there are also Sb₂O₂ and Sb₂Hal₂ rings, but the structures are probably different from those of 2 and 4 .     

Synthese,IR-Spektrum und Kristallstruktur von Sb12O18(OH)2Cl22 · 2CH2Cl2

Synthesis, IR Spectrum, and Crystal Structure of Sb₁₂O₁₈(OH)₂Cl₂₂ · 2CH₂Cl₂ The title compound has been prepared by the reaction of Sb₅O₇Cl₁₁ with dichloromethane at 20°C, forming colourless, moisture sensitive crystals. Sb₁₂O₁₈(OH)₂Cl₂₂ · 2CH₂Cl₂ crystallizes monoclinically in the space group P2₁/n with two formula units per unit cell. Structure solution with 2696 unique observed reflections, R = 0.042. Lattice dimensions at 19°C: a = 1350.2, b = 1466.7, c = 1392.9 pm, b? = 97.925°. The distorted octahedrally coordinated antimony atoms, bridged by oxygen atoms, exhibit a molecular array which may be seen as a fragment of the rutile type structure, isolated by terminal chloride ligands. The solvate molecule is associated by a hydrogen bridge OH···Cl.     

Cs5Sb8 und β‐CsSb: Zwei neue binäre Zintl‐Phasen

Cs₅Sb₈ and β‐CsSb: Two New Binary Zintl Phases The anion in the crystal structure of the new Zintl phase Cs₅Sb₈ synthesized from the elements (monoclinic, space group P2₁/c, a = 724.4(2) pm, b = 1135.2(3) pm, c = 2750.9(8) pm, β = 96.663(5)°, Z = 4) consists of two and three bonded Sb atoms, which are connected to form puckered nets with 5 and 28 membered rings. β‐CsSb (monoclinic, space group P2₁/c, a = 1519.4(3) pm, b = 734.0(2) pm, c = 1432.2(2) pm, β = 113.661(3)°, Z = 4) crystallizes with a superstructure of the LiAs structure type. As in the α phase (NaP type), twobonded Sb^‐ atoms form neary ideal 4₁ screx chains. In contrast to the α phase the helices have opposite chirality.     

Hydrothermalsynthese und Kristallstruktur des Diarsenates PbCuAs2O7

The monoclinic compound PbCuAs₂O₇ [a=5.553 (1),b=8.404 (1),c=13.011 (2) Å, =91.61 (2)° space group P2₁/n-C _2h ⁵ ;Z=4] was synthesized under hydrothermal conditions. The structure was solved by direct methods and was refined to anR value of 3.6%. The Pb atom is irregularly eight coordinated by O atoms, and the Cu atom tetragonal pyramidal [4+1] coordinated by O atoms. Each two AsO₄ tetrahedra share a common O atom corner building up As₂O₇ groups. These groups are connected with the CuO₄ polyhedra to sheets parallel (101). These sheets are combined by the PbO₈ polyhedra to a framework.

Herrn Prof. Dr.K. Komarek zum 60. Geburtstag gewidmet.     

Darstellung und Kristallstruktur von RbSb3Se5

Preparation and Crystal Structure of RbSb₃Se₅ RbSb₃Se₅ was prepared by methanolothermal reaction of Rb₂CO₃ with Sb₂Se₃ at a temperature of 175°C. An X-ray structural analysis demonstrated that the compound contains polyselenoantimonate(III) anions (Sb₃Se₅^?)_n. A ψ-tetrahedral coordination is observed for one of the independent Sb atoms, a ψ-trigonal bipyramidal coordination for the other two. The Sb? Se polyhedra are linked through joint edges into sheets.     

β-SrNH und β-SrND – Synthese und Kristallstrukturbestimmung mittels Röntgen- und Neutronenbeugung an Pulvern

β-SrNH and β-SrND – Synthesis and Crystal Structure Determination by X-Ray and Neutron Powder Diffraction By reaction of strontium with NH₃ in a flow tube at 750 °C a novel modification of strontium imide, β-SrNH, was obtained as a dark yellow powder. According to X-ray powder diffractometry und crystal structure determination by direct methods β-SrNH and β-SrND adopt a highly distorted variant of the NaCl type of structure (Pnma, a = 757.70(1), b = 392.260(4), c = 569.652(9) pm, Z = 4, wR_p = 0.098, R_p = 0.075, R_F = 0.044). Temperature dependent neutron powder diffraction of β-SrND revealed the position of the D atoms which in contrast to α-SrND are crystallographically ordered. At higher temperatures β-SrNH transforms to α-SrNH.     

The crystal structure and some properties of Eu2Sb3

The Mooser-Pearson phase Eu₂Sb₃ crystallizes in a new monoclinic structure type, space group $\text{P2}{}_1\text{c}$ (No. 14) with a = 6.570(1) Å, b = 12.760(2) Å, c = 15.028(2) Å, β = 90.04(1)°; Z = 8. The Sb atoms form six-membered twisted chain fragments oriented along the b-axis. The Eu atoms are eight- and nine-coordinated by Sb. The Eu₂Sb₃ structure is closely related to the structure of Ca₂As₃. The relations between their space-group symmetries are derived and hypothetical higher-symmetry structures are discussed. The semiconducting Eu₂Sb₃ is antiferromagnetic below T_N = 14.4°K. An Eu₂Sb₃-type structure was found also for Sr₂Sb₃.     

Zur Darstellung und Kristallstruktur von Rb2Sb4S7

On the Preparation and Crystal Structure of Rb₂Sb₄S₇ Rb₂Sb₄S₇ was prepared by methanolothermal reaction of Rb₂CO₃ with Sb₂S₃ at a temperature of 140°C. An X-ray structural analysis demonstrated that the compound contains polythioantimonate(III) anions (Sb₄S₇^2?)_n, for which the basic element is a ψ-trigonal (SbS₄)-bipyramid. Edge bridged SbS₄ polyhedra build vierer single chains (Sb₄S₈^4?)_n, which are linked via two symmetry related S atoms with neighbouring chains so that an (Sb₄S₇^2?)_n sheet is formed.     

Pentabromothio-diarsenat und -diantimonat: Darstellung,Schwingungsspektren und Kristallstrukturen von PPh4[As2SBr5] und PPh4[Sb2SBr5]

Pentabromothio-diarsenate and -diantimonate: Preparation, Vibrational Spectra, and Crystal Structures of PPh₄[As₂SBr₅] and PPh₄[Sb₂SBr₅] The title compounds were obtained in CH₂Br₂ from PPh₄Br, HBr and As₂S₃ or Sb₂S₃, respectively. Their i.r. and Raman spectra are reported. Their crystal structures were determined by X-ray diffraction. Crystal data: PPh₄[As₂SBr₅], monoclinic, space group P2₁/n, Z = 4, a = 1192.3, b = 1528.1, c = 1618.0 pm, β = 95.53°, isotypic with PPh₄[As₂SCl₅] (structure determination with 1539 observed reflexions, R = 0.052); PPh₄[Sb₂SBr₅], triclinic, space group P1 , Z = 2, a = 1044,8, b = 1207.1, c = 1307.8 pm, α = 104.77, β = 108.63, γ = 98.34° (2398 observed reflexions, R = 0.032). Both ions, [As₂SBr₅]^? and [Sb₂SBr₅]^?, have the same general structure: including the lone electron pairs, the As and Sb atoms have distorted trigonal-bipyrimidal coordination, two bipyramids sharing a common edge with sulfur and bromine as bridging atoms. The [As₂SBr₅]^? ions are associated to chains via As…Br contacts, the [Sb₂SBr₅]^? ions form pseudodimeric units by Sb…S and Sb…Br contacts. Whereas the crystal packing of the As compound is similar to that of other PPh₄⁺ compounds having a cation to anion ratio of 1:1, the Sb compound shows the packing principle known for 2:1 compounds.     

Crystal Structure and Magnetic Properties of SrNi2–xSb2

The intermetallic phase SrNi_2–xSb₂ was synthesized by arc melting mixtures of the elements and subsequent annealing under argon, and its structure was investigated by means of both powder and single‐crystal X‐ray diffraction methods. It crystallizes with the ThCr₂Si₂ type (tI10, I4/mmm) and has a homogeneity range of x = 0.15(1)–0.28(1), which does not include the exact stoichiometric 1:2:2 composition. The crystal structure of the phase SrNi_2–xSb₂ is built from layers of edge‐sharing Ni_1–xSb₄ tetrahedra, which are separated by Sr atoms along the c direction. Magnetic measurements of SrNi_2–xSb₂ showed no superconductive transition above 1.8 K.     

Phase relations and structural properties of the ternary narrow gap semiconductors Zn5Sb4In2−δ (δ=0.15) and Zn9Sb6In2

A systematic study of the Zn-rich corner of the ternary system Zn-Sb-In revealed the presence of two ternary compounds: stable Zn₅Sb₄In_2−δ (δ=0.15) and metastable Zn₉Sb₆In₂ with closely related crystal structures. Their common motif is a tetragonal basic structure of 3²434 nets formed by the Sb atoms. The nets are stacked in antiposition to yield layers of square antiprisms sharing edges plus intervening tetracapped tetrahedra (tetreadersterns). The majority of Zn atoms occupy peripheral tetrahedra of such tetraedersterns, which produces frameworks with a composition “ZnSb”. These frameworks represent orthorhombic superstructures: (2×1×1) for Zn₅Sb₄In_2−δ (Z=4) and (2×3×1) for Zn₉Sb₆In₂ (Z=8) with respect to the tetragonal arrangement of Sb atoms. The In and remaining Zn atoms are distributed in the channels formed by the square antiprisms. Phase relations in the Zn-Sb-In system are complex. Crystals of metastable Zn₉Sb₆In₂ are regularly intergrown with various amounts of Zn₅Sb₄In_2−δ. Additionally, a monoclinic variant to orthorhombic Zn₉Sb₆In₂ could be identified. Zn₉Sb₆In₂ decomposes exothermically into a mixture of Zn₅Sb₄In_2−δ, Zn₄Sb₃ and elemental Zn at around 480 K. Both Zn₅Sb₄In_2−δ and Zn₉Sb₆In₂ are poor metals with resistivity values that are characteristic of heavily doped or degenerate semiconductors (0.2−3 m Ω cm at room temperature).     

Towards Antimonene and 2D Antimony Telluride through Electrochemical Exfoliation

Two-dimensional (2D) layered antimony (Sb) and antimony telluride (Sb₂Te₃) are two valuable materials for optoelectronic devices and thermoelectric applications. Preparing high-quality sheets of these materials is the initial phase to promote their expected issues. Herein, micrometer-sized few-to-multilayered sheets of Sb and Sb₂Te₃ have been obtained by electrochemical exfoliation. The layered rhombohedral Sb was exfoliated in Na₂SO₄ and Li₂SO₄ electrolytes by anodic–cationic intercalation, and Sb₂Te₃ was exfoliated in Na₂SO₄. These findings are important contributions for the solution-based room-temperature electrochemical exfoliation, which is stable under glove-box-free conditions, to further improve the production of high-quality exfoliated sheets.     

Structural investigation of Cr2B3, Cr3B4, and CrB by single-crystal diffractometry

The crystal structures of Cr₂B₃, Cr₃B₄, and CrB, of which Cr₂B₃ is a new compound, were investigated by single-crystal X-ray diffractometry. Cr₂B₃ crystallizes in the orthorhombic space groupCmcm witha = 3.0264(5), b = 18.115(4), c = 2.9542(4)A˚, Z = 4. The intensity data were collected on a four-circle diffractometer with graphite-monochromatizedMoKα radiation. The structure was solved by the Patterson method and refined with a full-matrix least-squares program to anR value (= Σ|ΔF|Σ|F_o|) of 0.021 for 1310 reflections. The structures of Cr₃B₄ and CrB were refined starting from published data; theR values were 0.032 (Cr₃B₄) and 0.022 (CrB). The structure of Cr₂B₃ can be described by stacking sheets of the AlB₂ structure type in the same manner as in the cases of Cr₃B₄ and CrB. The fusion of two neighboring sheets is performed by a 5Cr tetragonal pyramid and a Cr-B direct bond at their boundary. The essential difference between the structures of these compounds is only in the widths of the sheets. The relations of the widths of the sheets to the bond distances and angles of boron atoms are discussed.     

Darstellung und Kristallstruktur der Pnictidoxide Na2Ti2As2O und Na2Ti2Sb2O

Preparation and Crystal Structure of the Pnictide Oxides Na₂Ti₂As₂O and Na₂Ti₂Sb₂O Na₂Ti₂As₂O and Na₂Ti₂Sb₂O were synthesized in form of very easily hydrolysed metallic-grey powders by reaction of Na₂O and TiAs resp. TiSb in sealed tantalum tubes under argon. The tetrahedral bodycentered crystallizing compounds from a modified anti-K₂NiF₄ structure type [1] (also called Eu₄As₂O-type [2,3]), space group I4/mmm (no. 139), with the lattice constants for Na₂Ti₂As₂O: a = 407.0(2) pm, c = 1528.8(4) pm and for Na₂Ti₂Sb₂O: a = 414.4(0) pm, c = 1656.1(1) pm. Magnetic measurements of powder samples of Na₂Ti₂Sb₂O show antiferromagnetic interaction within the Ti—O-layers. Superconductivity was not found by ac-shielding method down to 4 K.     

Synthese und Kristallstrukturen der Thiochloroantimonate(III) PPh4[Sb2SCl5] und (PPh4)2[Sb2SCl6] · CH3CN

Syntheses and Crystal Structures of the Thiochloroantimonates(III) PPh₄[Sb₂SCl₅] and (PPh₄)₂[Sb₂SCl₆]. CH₃CN (PPh₄)₂Sb₃Cl₁₁, obtained from Sb₂S₃, PPh₄Cl and HCl, reacts with Na₂S₄ in acetonitrile forming PPh₄[Sb₂SCl₅]. From this and Na₂S₄ or from (PPh₄)₂[Sb₂Cl₈] and Na₂S₄ or K₂S₅ in acetonitrile (PPh₄)₂[Sb₂SCl₆] · CH₃CN is obtained. Data obtained from the X-ray crystal structure determinations are: PPh₄[Sb₂SCl₅], monoclinic, space group P2₁/c, a = 1002.9(3), b = 1705.6(5), c = 1653.7(5) pm, β = 99.12(2)°, Z = 4, R = 0.068 for 1283 reflextions; (PPh₄)₂[Sb₂SCl₆] · CH₃CN, triclinic, space group P1 , a = 1287.8(7), b = 1343.6(9), c = 1696.5(9) pm, α = 69.82(5), β = 85.08(4), γ = 71.54(6)°, Z = 2, R = 0.059 for 6409 reflexions. In every anion two Sb atoms are linked via one sulfur and one ore two chloro atoms, respectively. Paris of [SbSCl₅]^? ions are associated via Sb …? S and Sb …? Cl contacts forming dimer units. In both compounds every Sb atom has a distorted octahedral coordination when the lone electron pair is included in the counting.     

Kristallstrukturen und chemische Bindung von AM2GeSe4 (A = Sr,Ba; M = Cu,Ag)

New Noncentrosymmetric Selenogermanates. I. Crystal Structures and Chemical Bonding of AM ₂GeSe₄ ( A = Sr, Ba; M = Cu, Ag) Three new quaternary selenogermanates were synthesized by heating the elements at 983–1073 K. Their crystal structures were determined by single crystal X‐ray methods. The dark red semiconductors crystallize in noncentrosymmetric space groups. SrCu₂GeSe₄ (Ama2, a = 10.807(4) Å, b = 10.735(4) Å, c = 6.541(2) Å, Z = 4) forms a new structure type, whereas BaCu₂GeSe₄ (P3₁, a = 6.490(1) Å, c = 16.355(3) Å, Z = 3) and BaAg₂GeSe₄ (I222, a = 7.058(1) Å, b = 7.263(1) Å, c = 8.253(2) Å, Z = 2) crystallize in structures known from thiostannates. Main structural features are almost regular GeSe₄‐, but distorted CuSe₄‐ or AgSe₄‐tetrahedra sharing corners or edges. Eight selenium atoms coordinate the alkaline earth atoms in the voids of these three dimensional tetrahedral networks. Chemical bonding and the electronic structure are elucidated by self‐consistent band structure calculations and the COHP method. The electron density and the electron localization function ELF of SrCu₂GeSe₄ reveal a significant stronger covalent character for the Ge–Se bonds compared with the Cu–Se bonds. For this reason the GeSe₄ tetrahedra appear as quasi molecular entities, arranged spatially according to the motifs of closest packing. The metal atoms occupy the tetrahedral and octahedral voids of these “tetrahedra packing”. This concept allows to derive the structures of AM₂GeSe₄‐compounds from simple binary structure types as Li₃Bi or Ni₂In.