Strukturen caesiumhaltiger Fluoride. VIII. Cs7Ni4F15 und Cs7Co4F15: Die Kristallstrukturbestimmung an den bisher caesiumreichsten Verbindungen in den zugehörigen Systemen CsF/MF2

Structures of Cesium-containing Fluorides. VIII. Cs₇Ni₄F₁₅ and Cs₇Co₄F₁₅: Crystal Structure Determination of the Hitherto Cesium-richest Compounds in the Corresponding Systems CsF/MF₂ . The only nickel-containing phase we could identify after solid state reaction 2 CsF + NiF₂ was the compound Cs₇Ni₄F₁₅. The single crystal structure determination of this monoclinic fluoride (and its cobalt analog Cs₇Co₄F₁₅) yielded a = 787.2 (788.3), b = 1089.7 (1096.6), c = 1149.5 (1164.9) pm, β = 92.74 (92.59)°, space group P2₁/c, Z = 2, R_g = 0.045 (0.058) for 2543 (2716) independent reflections. The resulting strongly puckered layer structure rather than of single octahedra consists of face-sharing M₂F₉ units, which are connected via the half of their remaining corners. The M? F distances vary from 195.1 to 212.0 (196.7 to 217.0) pm and show unusual high mean values of 203.7 (206.5) pm. Data for comparison and further details are discussed.     

CsCu5S3 – eine neue Verbindung in zwei Modifikationen

CsCu₅S₃ – A New Compound existing in two Modifications CsCu₅S₃ has been obtained in form of two modifications in a flux of cesium thiocyanate. Single crystal investigations revealed a tetragonal modification closely related to the structure of TlCu₅Se₃. The orthorhombic crystallizing modification can be described as a layer structure. The copper atoms in both atomic arrangements form arrays (fragment frame structures) of the fcc copper structure. At 582 °C the orthorhombic modification transforms easily into the tetragonal one, while the reverse reaction occurs very slowly.     

Strukturen caesiumhaltiger Fluoride. V. Die pseudohexagonale Wolframbronzestruktur der monoklinen Phase Cs0,4Zn0,4Fe1,6F6 und verwandter Cäsium-Übergangsmetallfluoride

Structures of Cesium-containing Fluorides. V. Pseudohexagonal Tungsten Bronze Structure of the Monoclinic Phase Cs_0.4Zn_0.4Fe_1.6F₆ and Related Cesium Transition Metal Fluorides The crystal structure of the pseudohexagonale phase Cs_0.4Zn_0.4Fe_1.6F₆ was refined in the monoclinic space group P2₁ (a = 747.4, b = 763.6, c = 746.1 pm, β = 120.0°, z = 3). Using 1067 single crystal reflections R = 6.3% was reached. Compared to the hexagonal tungsten bronze structure the corner-sharing of octahedra shows pronounced angles also along the unique axis (M? F? M = 159.0°). The average bridge angle in the framework of tilted octahedra is 149.6°. Structural relations are discussed.     

Ba2NiTeO6 – eine neue Verbindung in der Reihe der hexagonalen Perowskite

Ba₂NiTeO₆ — a novel compound in the series of hexagonal perovskites (Ba₂)(¹²)(NiTe)(⁶)O₆ crystallizes in the rhombohedral space group R3 m with a = 5.797 and c = 28.595 Å for the unit cell in the trigonal setting, which contains 6 formula units. The crystal structure was solved by single crystal X-ray diffraction and refined down to R = 2.9%. It can be described by 12 close-packed BaO₃ layers alternating in the sequence hhcchhcc…, with an ordered occupation of the octahedral lattice sites by Ni and Te atoms. Groups of three octahedra, which are connected with one another by common faces, are linked with each other by TeO₆ octahedra via common corners. The central octahedra of these face-linked groups are occupied by Te, the outer ones by Ni. The bonding within the NiO₆ polyhedra is discussed on the basis of the ligand field spectra and compared to similar compounds. It is shown that there can be an appreciable change of the ligand field parameter Δ (30%) even when the Ni — O distances are nearly equal — in contrast to the predictions of the crystal field theory. Effects of this kind are observed under certain structural conditions, when the bonding within the NiO₆ polyhedra is changed indirectly by substitution of atoms with a noble gas configuration (W⁶⁺) by atoms with a d¹⁰-configuration (Te⁶⁺) in the cationic environment of Ni²⁺.     

Fluoride und Fluorosäuren. V. Kristallstruktur der 1:4-Phase im System Wasser-Fluorwasserstoff und eine neue Untersuchung einer der 1:2-Phasen

Fluorides and Fluoro Acids. V. Crystal Structure of the 1:4 Phase in the System Water-Hydrogen Fluoride and a New Investigation of One of the 1:2 Phases In the quasi binary system H₂O? HF the 1:2 phase of known crystal structure was recognized as the stable high-temperature phase. A more accurate redetermination of its structure (monoclinic, space group P2₁/c, Z = 4, a = 3.477, b = 6.024, c = 11.358 Å, β = 96.70° at ?100°C, R = 0.032 for 1356 observed MoKα data) confirmed the previous results of a layer structure formed by strong hydrogen bonds. H₃OF · HF appears besides H₃OHF₂ as a possible structural formula. — The crystal structure of the 1:4 phase of the system was also determined (triclinic, P1 , Z = 2, a = 5.574, b = 6.429, c = 6.874 Å, α = 115.79, β = 96.63, γ = 108.79° at ?113°C, R = 0.049 for 1942 observed MoKα data). By strong hydrogen bonds the atoms form rings, which are condensed to parallel ribbons. Possible structural formulae, based on the distribution of interatomic distances, are H₃OH₃F₄, H₃OH₂F₃ · HF and H₃OF · 3 HF. — Interatomic distances in the hydrogen bonds F? H…?F and O? H…?F of both structures and the known one of the 1:1 phase are discussed in comparison.     

Darstellung,Kristallstruktur und elektronenmikroskopische Untersuchung von UNb6O16 – einem neuen niobreichen Oxid im System U/Nb/O

Preparation, Crystal Structure and Electron Microscopic Investigation of UNb₆O₁₆ – a New Niobium-rich Phase in the System U/Nb/O Powdery UNb₆O₁₆ was produced by heating (1 000°C or 1 100°C; evacuated silica tube) mixed powders of UO₂, NbO₂ and Nb₂O₅ (1:2:2). Single-crystals of UNb₆O₁₆ were obtained by chemical transport in a small temperature gradient (1 000°C → 990°C; transport agent NH₄Cl). The lattice constants are a = 22 339(4) Å; b = 3.7750(6) Å; c = 7.249(3) Å; β = 97.61(3)° and Z = 2. The structure determination (space group C2) let to R = 0.026 (R_w = 0.026). Eight oxygen atoms surround U⁴⁺ like a trans-bis-capped octahedron, Nb⁴⁺ and Nb⁵⁺ are coordinated distorted octahedraly. The structure was checked and the occupation of the positions O8 and O9 was clarified with the program MAPLE4 [3]. A through focus series of high resolution transmission electron microscopic images was obtained which is in acceptable agreement with images calculated on the basis of the multi-slice method.     

Caesiumchromhalogenide Cs3CrCl6, Cs3Cr2Cl9 und Cs3CrBr6 – Darstellung,Eigenschaften, Kristallstruktur

Cesium Chromium Halides Cs₃CrCl₆, Cs₃Cr₂Cl₉, and Cs₃CrBr₆ – Preparation, Properties, Crystal Structure The crystal structures of Cs₃CrCl₆ and Cs₃Cr₂Cl₉ were determined and redetermined by X‐ray single‐crystal studies (space group Pnnm, Z = 6, a = 1115.6(2) pm, b = 2291.3(5) pm, c = 743.8(1) pm, R_f = 7.73%, 1025 unique reflections with I > 2σ(I) (Cs₃CrCl₆); P6₃/mmc, Z = 2, a = 721.7(2) pm und c = 1791.0(1) pm; R_f = 2.06%, 395 unique reflections with I > 2.5σ(I) (Cs₃Cr₂Cl₉). The structure of Cs₃CrCl₆ consists of two different isolated CrCl₆ octahedra and five crystallographic different Cs⁺ ions. The CrCl₆ octahedra form ropes in the direction [001]. Because of orientational disordering of the Cr(1)Cl₆ octahedra and the an only half‐occupation of some cesium and chlorine sites Cs₃CrCl₆ is strongly disordered in direction of the (020) plane. The ionic conductivity of Cs₃CrCl₆, which was expected owing to the great disorder, however, is with 7.3 × 10^–5 Ω^–1 cm^–1 at 740 K relatively small. The compound Cs₃CrBr₆, which was firstly prepared by quenching stoichiometric amounts of CsBr and CrBr₃ from 833 K, is metastable at ambient temperature. It is probably isostructural to Cs₃CrCl₆ as shown by X‐ray powder photographs.     

Na5Br(OH)4: Darstellung und Kristallstruktur einer Verbindung im System NaOH/NaBr

Na₅Br(OH)₄: Synthesis and Structure of a Compound in the System NaOH/NaBr The pseudobinary system NaOH/NaBr is investigated by X-ray methods. The structure of the compound Na₅Br(OH)₄ was solved by single crystal data: Na₅Br(OH)₄: Pnma, Z = 8, a = 11.846(2) Å, b = 18.782(4) Å, c = 6.431(1) Å, Z(F_o) = 1 202 with (F_o)² ≥ 3σ(F_o)², Z(parameter) = 100, R/R_w = 0.030/0.035 The compound crystallizes in a new type of structure. Pairs of octahedra around O by 5 Na and 1 H to [Na₅(OH)]₂ are orientated in such a way to one another that two ions OH^? form a parallelogram hinting to unusual bent hydrogen bridge bonding.     

Cs6Re6S15 – eine Verbindung,in der [Re6S8]-Baueinheiten über Disulfidbrücken verknüpft eine Gerüststruktur bilden

Cs₆Re₆S₁₅ – a Compound, in which [Re₆S₈] Clusters are Linked by Disulphide-Bridges Giving a Framework Structure Cs₆Re₆S₁₅ was synthesized by the reaction of cesium carbonate with rhenium in a stream of H₂S at 800°C. Structural investigations on single crystals revealed an atomic arrangement in which [Re₆S₈] clusters are linked threedimensionally by S₂^2? bridges. Additionally inserted sulphide ions lead to the formula Cs₆S{[Re₆S₈](S₂)_6/2}. The nearly regular Re₆-octahedra correspond with a 24-electron configuration.     

AlCl3 · 2NH3 – eine Verbindung mit der Kristallstruktur eines Tetraammindichloroaluminium-tetrachloroaluminats – [AlCl2(NH3)4]+[AlCl4]−

ACl₃ · 2NH₃ – a Compound with the Crystal Structure of a Tetraammine Dichloroaluminiumtetrachloroaluminate – [AlCl₂(NH₃)₄]⁺[AlCl₄]^? Ammoniates of aluminiumchloride AlCl₃ · xNH₃ are in discussion as starting materials for the synthesis of aluminiumnitride. Therefore the reactions of melts of monoamminealuminiumchloride with ammonia were investigated. They react at 150°C within 10 min with one mole of ammonia to the diammoniate, [AlCl₂(NH₃)₄]⁺[AlCl₄]^?. The pure compound can be obtained by sublimation at 200°C in vacuumline apparatus. X-ray structure determination on [AlCl₂(NH₃)₄]⁺[AlCl₄]^? was carried out: see “Inhaltsübersicht”.     

Die Schwingungsspektren und Kraftkonstanten der Anionen MoOF–5 MoOF2–5, MoF–6 und WOF–5

Inhaltsübersicht. Die Schwingungsspektren der Verbindungen CsMoOF₅, MWOF₅ (M = K, Rb, Cs), K₂MoOF₅, K₂MoOF₅ · H₂O, K₂MoOF₅ · KHF₂ und MMoF₅ (M = K, Cs) wurden aufgenommen und zugeordnet. Aus den so ermittelten Normalschwingungsfrequenzen wurden für die Ionen MoOF₅^–, WOF₅^–, MoOF₅^2– und MoF^–₅ Kraftkonstanten nach einem modifizierten Valenzkraftfeld berechnet. Anhand der erhaltenen Werte der Valenzkraftkonstanten werden die Bindungs-verhältnisse diskutiert. Vibrational Spectra and Force Constants of the Anions M0OF₅^–, MoOF₅^2–, MoF^–₆, and WOF₅^– Abstract. The vibrational spectra of CsMoOF₅, MWOF₅ (M = K, Rb, Cs), K₂MoOF₅, K₂MoOF₅ · H₂O, K₂MoOF₅ · KHF₂, and MMoF₅ (M = K, Cs) have been recorded and assigned. The vibrational frequencies were used to calculate MVFF constants for the ions MoOF₅^–, WOF₅^–, MoOF₅^2–, and MoF^–₆. The stretching force constants are discussed relative to the bond properties.     

Über die Reaktion von HCl im System HF/SbF5 und die Kristallstruktur von SbCl3F2

On the Reaction of HCl with HF/SbF₅ and the Crystal Structure of SbCl₃F₂ The reaction of HCl in HF/SbF₅ solution at ?78°C yields H₂F⁺SbClF₅^?. At ?40°C formation of SbCl₃F₂ was observed, which crystallizes in the tetragonal space group I-4 with a = 1 281.6(5) pm, c = 758.1(6) pm with 8 formula units per unit cell. The structure contains cis-fluorine-bridged tetramers, in which Sb has a distorted octahedral coordination.     

Cs2Cu3MIVF12 (MIV = Zr,Hf) – Kristallstruktur und magnetische Eigenschaften

Cs₂Cu₃M^IVF₁₂ (M^IV = Zr, Hf) – Crystal Structure and Magnetic Behaviour Colourless single crystals of Cs₂Cu₃ZrF₁₂ are obtained by heating the binary fluorides in sealed Pt-tubes under dry argon (solid state reaction, T ≈? 700°C, t ≈? 7–10 d). The compound crystallizes trigonal-rhomboedrical in the space group R3 m-D (Nr. 166); lattice parameters are a = 716.61(6) pm, c = 2 046.4(2) pm, Z = 3 (Four cycle diffractometer data, AED 2). The structure is dominated by layers of corner-sharing, Jahn-Teller-distorted [CuF₆]-Octahedra, which are connected via regular [ZrF₆]-Octahedra to stackings parallel [00.1]. Cs⁺-ions are located in the spacings of the octahedra-network. From powder data Cs₂Cu₃HfF₁₂ with a = 716.32(4) pm, c = 2 048.6(2) pm is isotypic. Both compounds show antiferromagnetic behaviour already at temperatures about 200 K.     

Synthese von (C6F5)2SF+MF6− (M  As,Sb) und Kristallstruktur von (C6F5)2SF+SbF6− [1]

Preparation of (C₆F₅)₂SF⁺MF₆^? (M ? As, Sb) and Crystal Structure of (C₆F₅)₂SF⁺SbF₆^? XeF⁺MF₆^? (M ? As, Sb) reacts with (C₆F₅)₂S in HF to form (C₆F₅)₂SF⁺MF₆^?. The deeply violet sulfonium salts can be kept without decomposition up to 24 h at room temperature. The hexafluoroantimonate salt crystallizes in the monoclinic space group P2₁/n with a = 1056.4(7) pm, b = 1446.3(10) pm, c = 1102.9(8) pm, β = 91.29(6)° und Z = 4. The SF-bond distance with 158.4(3) pm is of unusual length. Cations and anions are connected via interionic fluorine contacts to an infinite chain, in which cations and anions form to ABAB sequence along the chain.     

Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen. XXXIV. Fehlgeordnete Strukturen mit Großen Blöcken im System Nb2O5/WO3 — Elektronenmikroskopische Untersuchung

Contributions to the Investigation of Inorganic Non-stoichiometric Compounds. XXXIV. Disordered Structures Consisting of Large Blocks in the System Nb₂O₅/WO₃. An Electronmicroscopical Investigation The real structures of samples which have been prepared by quenching procedures using the composition Nb₂O₅: WO₃ = 10:11 are in most cases heavily disordered; some areas show extremly large blocks. The electron microscopic investigation revealed that the blocks consist of [n × m] M? O octahedra and have edge lengths of n = 5 to 14 and of m = 5 to 13 and in one case we even found [n × m] = [5 × 32]. In comparison, samples that were heated below the melting point for a longer time, showed a less disordered structure. Block sizes of [5 × 6] to [5 × 9] in a matrix of [5 × 5] blocks could be observed.