Die Kristall- und Molekülstrukturen von (Me2SiNCN)4 (1) und Me3SiNCNSiMe3 (2)

Crystal and Molecular Structures of (Me₂SiNCN)₄ (1) and Me₃SiNCNSiMe₃ (2) Synthesis, spectroscopic characterization (NMR, IR, Raman and MS) and crystal structure of the novel compound 1 are described. The molecules form almost planar 16 membered rings with four SiMe₂-groups connected to four NCN groups. The corresponding compound 2 exhibits a phase transition from the HT phase 2a to the LT phase 2b at 131 K. Consecutive X-ray structure determinations of the molecular structures of both modifications were performed on a crystal, grown in situ on the diffractometer at 231 K.     

Struktur und magnetische Eigenschaften von Cs2Mn3S4 und Cs2Co3S4

Structure and Magnetic Properties of Cs₂Mn₃S₄ and Cs₂Co₃S₄ The atomic arrangements of the isotypic compounds Cs₂Mn₃S₄ and Cs₂Co₃S₄ were determined by X-ray investigations on single crystals (space group Ibam, Z = 4). To interprete the magnetic properties of Cs₂Mn₃S₄ mixed crystals of the series Cs₂(Mn_xZn_1-x)₃S₄ have been examined. Additionally neutron diffraction experiments were carried out and yielded the spin structures of Cs₂Mn₃S₄ and Cs₂Co₃S₄ (Shubnikov space group Ibam'). The deviations of the magnetic moments from those expected for high-spin d⁵ ions are explained by means of crystal field calculations.     

PPh4[As3S3Cl4] und PPh4[As3S3Br4]

PPh₄[As₃S₃Cl₄] and PPh₄[As₃S₃Br₄] When As₂S₃ reacts with PPh₄X and HX in 1,2-C₂H₄X₂ (X = Cl, Br), the title compounds are obtained as minor products; the main products are PPh₄[As₂SX₅]. Their crystal structures were determined by X-ray diffraction. PPh₄[As₃S₃Cl₄]: a = 1187.7, b = 1090.9, c = 1191.8 pm, α = 82.91, β = 88,93, γ = 88.52°; twins with twin plane (100); R = 0.109 for 1618 observed reflexions of one twin crystal. PPh₄[As₃S₃Br₄]: a = 1119.7, b = 1177.5, c = 1204.1 pm, α = 81.59, β = 85.88, γ = 88.25°; R = 0.061 for 2331 observed reflexions. Both compounds crystallize in the space group P1 , Z = 2, and can be considered to be isotypic. Nevertheless, PPh₄[As₃S₃Br₄] does not form twins as PPh₄[As₃S₃Cl₄]. The crystals consist of PPh₄⁺ and [As₃S₃X₄]^? ions. In the anions, the three As atoms of an As₃S₃ ring in the chair conformation are commonly joined to an X atom and each As atom is bonded to one further terminal X atom. Cations and anions are packed in alternating layers.     

Darstellung und Kristallstruktur von Ba3CdSn2S8 mit einer Anmerkung über Ba6CdAg2Sn4S16

Preparation and Crystal Structure of Ba₃CdSn₂S₈ Including a Notation about Ba₆CdAg₂Sn₄S₁₆ Ba₃CdSn₂S₈ (A) and Ba₆CdAg₂Sn₄S₁₆ (B) were prepared for the first time and the crystal structure was determined using single crystal data of (A). (A) and (B) are isotypic. Space group and lattice constants see “Inhaltsübersicht”. The crystal structure is described and discussed.     

Synthese und Kristallstrukturen der quaternären Chalkogenidchloride AgBi2S3Cl und AgBi2Se3Cl

Synthesis and Crystal Structures of the Quaternary Chalcogenide Chlorides AgBi₂S₃Cl and AgBi₂Se₃Cl Grey crystals of AgBi₂S₃Cl and AgBi₂Se₃Cl were synthesized from AgCl and Bi₂S₃ or Bi₂Se₃by cooling stoichiometric melts from 790 K to room temperature. X‐ray diffraction on powders and single‐crystals revealed that the compounds crystallize isostructural with space group type P 2₁/m. In the crystal structure of AgBi₂S₃Cl the bismuth(III) cations have a capped trigonal prismatic coordination of sulfide and chloride ions. The prisms constitute a three‐dimensional framework by sharing common edges and faces. Silver(I) cations, which have a distorted octahedral coordination of sulfide ions, fill linear channels. Parallels to the crystal structures of Cu₃Bi₂S₄Cl and Pr₂Br₅ can be seen.     

Kristallstruktur und Phasenumwandlungen von As(CH3)4I

Crystal Structure and Phase Transitions of As(CH₃)₄I The crystal structure of α-As(CH₃)₄I at room temperature was determined using single crystal data: cubic, space group Pa3 , a = 1 198.0(2) pm. Therefore α-As(CH₃)₄I displays a novel crystal structure, which is not comparable to known AB-Typ structures with respect to the arrangement of anions and the baricenters of the complex cations. Differential thermal analysis showed three phase transitions at 103, 175 and 215°C. The lattice parameters of the high temperature phases (temperature dependent Guinier measurements) are: β-As(CH₃)₄I (tetragonal): a = 845.2(2) pm, c = 615.0(2) pm; γ-As(CH₃)₄I (hexagonal): a = 737.7(2) pm, c = 1 082.2(3) pm; and to δ-As(CH₃)₄I (hexagonal): a = 705.8(2) pm, c = 1 147(1) pm. β-and γ-As[(CH₃)]₄I are isotypic to N(CH₃)₄Cl and As(CH₃)₄Br, respectively.     

Synthese und Kristallstrukturen von (PPh4)2[In(S4)(S6)Cl] und (PPh4)2[In(S4)Cl3]

Synthesis and Crystal Structures of (PPh₄)₂[In(S₄)(S₆)Cl] and (PPh₄)₂[In(S₄)Cl₃] InCl and PPh₄Cl yield (PPh₄)₂[In₂Cl₆] in acetonitrile. This reacts with Na₂S₄ in presence of PPh₄Cl, forming (PPh₄)₂[In(S₄)(S₆)Cl]. Its crystal structure was determined by X-ray diffraction (R = 0.075, 2 282 observed reflexions). It is isotypic with (PPh₄)₂[In(S₄)(S₆)Br] and contains anions with trigonal-bipyramidal coordination of In, Cl occupying an axial position, and the S₄ and S₆ groups being bonded in a chelate manner. The reaction of (PPh₄)₂[In₂Cl₆] and sulfur in acetonitrile yielded (PPh₄)₂[InCl₅] and (PPh₄)₂[In(S₄)Cl₃]. The crystal structure analysis of the latter (R = 0.072, 4 080 reflexions) revealed an anion with distorted trigonal-bipyramidal coordination of In, the S₄ group occupying one axial and one equatorial position; the S₄ group shows positional disorder.     

Die Kristallstrukturen von Ta2S2C und Ti4S5 (Ti0,81S)

A complex carbide with formula Ta₂S₂C prepared by sintering can be transformed by mechanical grinding into a modification having a very simple crystal structure. The lattice parameters of this compound (1s-Ta₂S₂C) were found to be:a=3.26₅,c=8.53₇ andc/a=2.61₅. The atomic positions are (space group \(P\bar 3ml\) ): $$\begin{gathered} 2 Ta in 2 d) (z = 0.141) \hfill \\ 2 S in 2 d) (z = 0.65) \hfill \\ 1 C in 1 a \hfill \\ \end{gathered} $$ A proposal for the atomic arrangement is presented for the high temperature phase 3s-Ta₂S₂C with the parameters:a _H=3.27₆ c _H=25.6₂ Å andc/a=7.82, space group \(R\bar 3m\) . The crystal structure of Ti₄S₅ has been determined from single crystal patterns. The lattice parameters are:a=3.439,c=28.93 Å andc/a=8.413. The atomic positions (space group P 6₃/mmc) are: 2 Ti in 2 a), 2.6 Ti in 4 e) (z=0.1055); 3.5 Ti in 4 f) (z=0.197); 2 S in b); 2 4 S in 4 f) (z=0.052) and 4 S in 4 f) (z=0.649).     

Synthese und Röntgenstrukturanalyse des Additionsproduktes von Schwefeltrioxid an Tetraschwefeltetranitrid (S4N4· SO3)

Synthesis and X-ray Structure Analysis of the Addition Compound of Sulfurtrioxide and Tetrasulfurtetranitride (S₄N₄· SO₃) S₄N₄ · SO₃ was obtained by reaction of S₄N₄ with SO₃ in CH₂Cl₂ and by solvent free reaction of S₄N₄ with Fluorosulfonic acid anhydride. The structure of the adduct could be determined by single crystal X-ray structure analysis. The “cage” of the S₄N₄ is analogous to the structure of S₄N₄ · SbCl₅ reconvoluted into a deformated saddle conformation with nearly C_s-symmetry. The S? N bond lengths in the S₄N₄ ring vary from 1.51 to 1.69 Å. The C_s-symmetry is significantly disturbed by the position of the SO₃ group. In the crystal structure with monoclinic unit cell of space group P2₁/n the molecules are packed into columns, which are arranged pseudohexagonally.     

Ba3V2S4O3: A Mott Insulating Frustrated Quasi‐One‐Dimensional S=1 Magnet

Through a solid‐state reaction, a practically phase pure powder of Ba₃V₂S₄O₃ was obtained. The crystal structure was confirmed by X‐ray single‐crystal and synchrotron X‐ray powder diffraction (P6₃, a=10.1620(2), c=5.93212(1) Å). X‐ray absorption spectroscopy, in conjunction with multiplet calculations, clearly describes the vanadium in charge‐disproportionated V^IIIS₆ and V^VSO₃ coordinations. The compound is shown to be a strongly correlated Mott insulator, which contradicts previous predictions. Magnetic and specific heat measurements suggest dominant antiferromagnetic spin interactions concomitant with a weak residual ferromagnetic component, and that intrinsic geometric frustration prevents long‐range order from evolving.     

Aufbau und Abbau von (NH4)[BF4] und H3N‐BF3

Production and Decomposition of (NH₄)[BF₄] and H₃N‐BF₃ (NH₄)[BF₄] is produced as single crystals during the reaction of elemental boron and NH₄HF₂ (B : NH₄HF₂ = 1 : 2) and NH₄F (B : NH₄F = 1 : 4), respectively, in sealed copper ampoules at 300 °C. The crystal structure (baryte type, orthorhombic, Pnma, Z = 4) was redetermined at ambient temperature (a = 909.73(18), b = 569.77(10), c = 729.47(11) pm, R_all = 0.0361) and at 140 K (a = 887.3(2), b = 574.59(12), c = 717.10(12) pm, R_all = 0.0321). Isolated (NH₄)⁺ and [BF₄]^— tetrahedra are the important building units. The thermal behaviour of (NH₄)[BF₄] was investigated under inert (Ar, N₂) and reactive conditions (NH₃) with the aid of DTA/TG and DSC measurements and with in‐situ X‐ray powder diffraction as well. Finally, (NH₄)[BF₄] is decomposed yielding NH₃ and BF₃, BN is not produced under the current conditions. Colourless single crystals of H₃N‐BF₃ were prepared directly from the components NH₃ and BF₃. The crystal structure was determined anew at 293 and 170 K (orthorhombic, Pbca, Z = 8, a = 815.12(10), b = 805.91(14), c = 929.03(12) pm, R_all = 0.0367; a = 807.26(13), b = 800.48(10), c = 924.31(11) pm, R_all = 0.0292, T = 170 K). The crystal structure contains isolated molecules H₃N‐BF₃ in staggered conformation with a B‐N distance of 158 pm. The thermal behaviour of H₃N‐BF₃ was studied likewise.     

Verbindungen mit Schichtstrukturen in den Systemen CuGa5S8/CuIn5S8 und AgGa5S8/AgIn5S8

Compounds with Layered Structures in the Systems CuGa₅S₈/CuIn₅S₈ and AgGa₅S₈/AgIn₅S₈ The title systems have been investigated by single crystal and powder X‐ray diffraction methods on quenched samples. In the system AgGa_xIn_5–xS₈ spinel type phases are formed up to x < 2. A compound crystallising with a hexagonal layered structure is obtained for 2 < x ≤ 3. The crystal structure of this layered phase has been solved on a single crystal of composition AgGa₃In₂S₈: space group P6₃mc, Z = 2, a = 380.80 and c = 3076.4 pm. The structure is isotypic to the Zn₂In₂S₅ (II a) type. The sample AgGa₄InS₈ crystallises in a Wurtzite like structure with a = 377.25 and c = 616.1 pm. In the system CuGa_xIn_5–xS₈ a new compound with layered structure has been detected for 1 ≤ x ≤ 2 which crystallises hexagonally with a = 380.28 and c = 3073.4 pm (x = 2). For the spinel CuIn₅S₈ an exchange of In by Ga is not detected.     

Darstellung und Kristallstruktur von Cs2Sb4S7

Preparation and Crystal Structure of Cs₂Sb₄S₇ The first thioantimonite of Cesium has been synthesized and its crystal structure determined. The substance crystallizes monoclinic with spacegroup P2₁/_c. The lattice constants are a = 1111.2(5) pm, b = 1227.1(5) pm, c = 1163.7(5) pm and ß = 97.60(5)°. There are four formula units in the unit cell. Sb–S chains are formed by trigonal SbS₃ pyramids and ψ-trigonal SbS₄ bipyramids.     

CsNb3Br7S: Synthese,Struktur und Bindungsverhältnisse

CsNb₃Br₇S: Synthesis, Structure, and Bonding States The reaction of NbBr₅ with Nb, Cs and S in a sealed Nb container affords CsNb₃Br₇S at 800°C (3 days). Further on isotypic compounds of the general formula ANb₃X₇Ch with A = Rb, Cs; X = Cl, Br and Ch = S, Se are obtained. CsNb₃Br₇S crystallizes monoclinic (space group P2₁/a, Z = 2), with the lattice parameters a = 707.4(2), b = 1 888.4(4), c = 994.1(2) pm and β = 98.59(2)°. The crystal structure contains Nb₃ clusters being linked by two additional Nb? Nb bonds to form infinite chains. Adjacent chains are bridged by Cs atoms in a cubeoctahedral coordination sphere of Br atoms. Similar with Nb₃Br₈ seven electrons occupy metal—metal bonding states.     

Tief-Tl3PbBr5, Darstellung und Kristallstruktur

Low-Tl₃PbBr₅, Preparation and Crystal Structure Single crystals of the low temperature modification of Tl₃PbBr₅ were prepared below the upper stability border with 239°C. X-ray investigations yield the following crystallografic data: orthorhombic system, space group P2₁2₁2₁, crystal axis a = 15.399, b = 9.063, c = 8.532 Å. The crystal structure is described in relation to the high temperature modification. Conductivity measurements aimed to demonstrate the diffusion of metal ions during phase transition.     

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.     

Phasendiagramm des quasibinären Systems NiCr2S4–NiGa2S4, Kristallstruktur des NiGa2S4

Phase Relationship of the Quasibinary System NiCr₂S₄? ;NiGa₂S₄, Crystal Structure of NiGa₂S₄ The quaternary system NiCr_2–2xGa_2xS₄ was studied with the help of X-ray powder Guinier photographs of quenched samples. The crystal structure of ternary NiGa₂S₄, not found formerly, was determined using single crystal data. The structure (trigonal space group P3 m1, Z = 1, a = 362.49(2), c = 1199.56(5) pm) consists of hexagonal close-packed sulfur with Ni and Ga in one fourth of the octahedral and tetrahedral holes, respectively (FeGa₂S₄ type). The S? ;S distance of the S? ;Ni? ;S layered units is unusually small, vic. 321.1 pm. The infrared spectrum of NiGa₂S₄ and a group theoretical treatment of the FeGa₂S₄ type lattice modes are given. Up to 20 mol % Ga of the layered NiGa₂S₄ can be substituted by Cr whereby Ni is possibly transfered from octahedral to tetrahedral sites. The phase width of monoclinic Cr₃S₄ type NiCr₂S₄ is very small possibly due to the metal-metal interaction in this NiAs defect structure. In the range 0.18 ? x ? 0.35 quaternary spinel type mixed crystals are formed.     

Darstellung und Kristallstruktur von Rb2Sb4S7

Preparation and Crystal Structure of Rb₂Sb₄S₇ The first thioantimonite of rubidium has been synthesized and its crystal structure determined. The substance crystallizes triclinic with spacegroup P1 . The lattice constants are a = 968.0(5) pm, b = 1193.4(5) pm, c = 723.1(5) pm, α = 87.68(5)°, β = 101.39(5)° and γ = 102.66(5)°. There are two formula units in the unit cell.     

Die Kristallpackung in drei Modifikationen von PPh4[ReO(S4)2] und PPh4[ReS(S4)2]

The Crystal Packing in three Modifications of PPh₄[ReO(S₄)₂] and PPh₄[ReS(S₄)₂] Mixed crystals PPh₄[ReS(S₄)₂]_0,63[ReO(S₄)₂]_0,37 were obtained from PPh₄Cl, ReCl₅ and Na₂S₄ in acetonitrile. Their crystal structure corresponds to the known structure of this kind of compound (space group P2₁/n). In a similar reaction with ReBr₅ instead of ReCl₅, PPh₄[ReO(S₄)₂] was obtained in small yield. Its triclinic crystal structure was determined by X‐ray crystallography (space group P1). It contains cation pairs (PPh₄⁺)₂ such as they have been found in many other instances. In contrast, the crystal structures of the mixed crystals and of one known modification of PPh₄[ReS(S₄)₂] have PPh₄⁺ columns similar to compounds crystallizing in the space group P4/n, albeit in a severely distorted manner; their space group P2₁/n is a subgroup of P4/n with a doubled unit cell. In another modification of PPh₄[ReS(S₄)₂] (space group P2₁/c) the columns are less distorted, but arranged in a different way.