Crystal structures of sodium magnesium selenate decahydrate,Na2Mg(SeO4)2·10H2O,a new selenate salt,and sodium magnesium selenate dihydrate,Na2Mg(SeO4)2·2H2O

Metal selenates crystallize in many instances in isomorphic structures of the corresponding sulfates. Sodium magnesium selenate decahydrate, Na₂Mg(SeO₄)₂·10H₂O, and sodium magnesium selenate dihydrate, Na₂Mg(SeO₄)₂·2H₂O, were synthesized by preparing solutions of Na₂SeO₄ and MgSeO₄·6H₂O with different molar ratios. The structures contain different Mg octahedra, i.e. [Mg(H₂O)₆] octahedra in the decahydrate and [MgO₄(H₂O)₂] octahedra in the dihydrate. The sodium polyhedra are also different, i.e. [NaO₂(H₂O)₄] in the decahydrate and [NaO₆(H₂O)] in the dihydrate. The selenate tetrahedra are connected with the chains of Na polyhedra in the two structures. O—H…O hydrogen bonding is observed in both structures between the coordinating water molecules and selenate O atoms.     

Mixed Valence Tungsten(IV,V) Compounds with Layered Structures (Part II)): Synthesis and Crystal Structures of Cu1−x[W2O2Cl6] and Cu1−x[W4O4Cl10]

The reaction of CuCl with WOCl₃ at 400 °C leads to a mixture of Cu_1?x[W₂O₂Cl₆] ( 1 ) and Cu_1?x[W₄O₄Cl₁₀] ( 2 ) in form of black lustrous needles. Both compounds crystallize in space group C2/m with a = 12.7832(5) Å, b = 3.7656(2) Å, c = 10.7362(3) Å, β = 119.169(2)° for 1 and a = 12.8367(19) Å, b = 3.7715(7) Å, c = 15.955(3) Å, β = 102.736(5)° for 2 . The structures are made up of WO₂Cl₄ octahedra. In the case of 1 two octahedra are edge‐sharing via chlorine atoms to form pairs which are linked via the trans‐positioned oxygen atoms to form infinite double strands . In the structure of 2 two of these double strands are condensed via terminal chlorine atoms to form quadruple strands . Like for all members of the M_x[W₂O₂X₆] structure family (X = Cl, Br) nonstochiometry with respect to the cations M was observed. The copper content of 1 and 2 was derived from the site occupation factors of the respective structure refinements. For several crystals examined the copper content varied between x = 0.27 and 0.17 for 1 and x = 0.04 for 2 . In both structures the oxochlorotungstate strands are negatively charged and connected to layers by the monovalent copper ions, which are tetrahedrally coordinated by the non‐bridging chlorine atoms of the strands. The structure models imply disorder of the Cu⁺ ions over closely neighboured sites.     

Sodium 5‐nitro‐2‐pyridonate trihydrate

The title compound, alternatively sodium pyridin‐2‐olate trihydrate, Na⁺·C₅H₃N₂O₃^?·3H₂O, crystallizes in the P space group. It is made up of edge‐shared chains of NaO₆ octahedra with five water mol­ecules and one 5‐nitro‐2‐pyridonate anion. Four of these water mol­ecules are bicoordinating, involved in connecting the adjacent octahedra, and the fifth is coordinated to only one octahedron. The crystal structure is stabilized by a network of strong O—H?O and O—H?N interactions. The organic moieties occupy the space between the chains with an antiparallel alignment.     

Doppelkettenstruktur von (pipzH2)[MnF2(HPO4)(H2O)](H2PO4)

By adding piperazine to a hydrofluoric and phosphoric acid solution of Manganese(III) fluoride, the fluoride phosphate (pipzH₂)[MnF₂(HPO₄)(H₂O)](H₂PO₄) can be crystallized. Its structure is built by piperazinium(2+) cations, (H₂PO₄)^? anions, and an anionic double‐chain of [HPO₄] tetrahedra and [MnO₃F₂(H₂O)] octahedra. The structure is triclinic, space group P , Z = 2, a = 622.97(4), b = 923.46(6), c = 1183.62(7) pm, α = 98.343(6)°, β = 100.747(7)°, γ = 107.642(5)°, R = 0.0289. It is worth noting that a ferrodistortive Jahn‐Teller order is observed with [MnO₃F₂(H₂O)] octahedra strongly elongated along the F–Mn–OH₂ axes perpendicular to the chain plane. The structure is stabilized by very strong hydrogen bonds.     

Na6(H2O)20(V10O28)·4H2O,a novel polyvanadate(V) with a three‐dimensional framework

The novel title polyvanadate(V), poly[[octa‐μ‐aqua‐dodecaaqua‐μ₄‐octacosaoxidodecavanadato‐hexasodium] tetrahydrate], [Na₆(H₂O)₂₀(V₁₀O₂₈)·4H₂O]_n, contains [V₁₀O₂₈]⁶⁻ anions which lie about inversion centres and have approximate 2/m symmetry and which are linked to [Na₃(H₂O)₁₀]³⁺ cations through two terminal and two μ₂‐bridging O atoms. The structure contains three inequivalent Na⁺ cations, two of which form [Na₂(H₂O)₈]_n chains, which are linked via NaO₆ octahedra involving the third Na⁺ ion, thus forming a three‐dimensional framework.     

Hexalithium hexadecahydrate decavanadate, [Li6(H2O)16V10O28]n

The novel title compound, poly­[octa‐μ‐aqua‐octa­aqua‐μ‐decavanadato‐hexalithium], contains [V₁₀O₂₈]⁶⁻ polyanions with 2/m symmetry linked by centrosymmetric [Li₆(H₂O)₁₆]⁶⁺ cation chains. The [V₁₀O₂₈]⁶⁻ polyanions form a two‐dimensional network with [Li₆(H₂O)₁₆]⁶⁺ chains via O‐polyanion–Li‐chain coordination, with Li—O bond lengths in the range 2.007 (5)–2.016 (5) Å. The hexalithium hexadecahydrate chain is composed of a centrosymmetric pair of LiO₆ octahedra and four distorted LiO₄ tetrahedra. Hydro­gen bonds occur between the polyanion and the Li‐based chains, and within the Li‐based chains.     

Preparation and crystal structure of copper tetrasodium trimetaphosphate tetrahydrate: CuNa4(P3O9)2 · 4H2O

The preparation of copper-tetrasodium trimetaphosphate tetrahydrate: Na₄Cu(P₃O₉)₂ · 4H₂O is described. This salt is the first example of the occurence of Cu^II in a trimetaphosphate. The triclinic unit cell has the dimensions a = 7.907(5), b = 8.364(5), c = 7.122(5) Å, α = 102.46(5), β = 97.89(5), γ = 84.04(5)°. Crystal structure has been solved by using 2019 independent reflexions with a final R value 0.017. Both copper and sodium atoms are in octahedral coordination. NaO₆ octahedra form ribbons running in (011) planes. These ribbons are interconnected by CuO₆ octahedra as to form a three dimensional network. Hydrogen atoms have been located and refined. The hydrogen bond scheme is described.     

(m‐CH3C6H4NH3)6P6O18

In hexakis(m‐toluidinium) cyclo­hexaphosphate, 6C₇H₁₀N⁺·­P₆O₁₈^6?, the atomic arrangement is typical of a layer structure. Layers including the centrosymmetric P₆O₁₈ ring anions develop around the (100) planes at x = . The hydrogen‐bond distribution is described.     

Nickel vanadium tellurium oxide,NiV2Te2O10

Single crystals of nickel(II) divanadium(V) ditellurium(IV) decaoxide, NiV₂Te₂O₁₀, were synthesized via a transport reaction in sealed evacuated silica tubes. The compound crystallizes in the triclinic system (space group P). The Ni atoms are positioned in the 1c position on the inversion centre, while the V and Te atoms are in general positions 2i. The crystal structure is layered, the building units within a (010) layer being distorted VO₆ octahedra and NiO₆ octahedra. The metal–oxide layers are connected by distorted TeO₄E square pyramids (E being the 5s² lone electron pair of Te^IV) to form the framework. The structure contains corner‐sharing NiO₆ octahedra, corner‐ and edge‐sharing TeO₄E square pyramids, and corner‐ and edge‐sharing VO₆ octahedra. NiV₂Te₂O₁₀ is the first oxide containing all of the cations Ni^II, V^V and Te^IV.     

Zur Kenntnis von Ba10Fe8Pt2Cl2O25

About Ba₁₀Fe₈Pt₂Cl₂O₂₅ The crystal structure of Ba₁₀Fe₈Pt₂Cl₂O₂₅ has been solved by direct methods, using intensity data collected by means of an automatic diffractometer (MoKα). It crystallizes in the hexagonal space group D–P6₃/mmc: a = 5.8034(4) Å, c = 24.997(5) Å, Z = 1. Fe³⁺ ions occur in both octahedral and tetrahedral coordination. Two types of Ba²⁺ ions are formed, with ten and twelve neighbouring atoms. The structure consists of plane connected FeO₆ and PtO₆ octahedra which are connected by corner shared FeO₄ tetrahedra.     

The polyoxometallate [(CH3)4N]2[Mo4O10(OCH3)4Cl2]

The crystal and molecular structure of bis(tetra­methyl­ammonium) di­chloro­tetra‐μ₂‐methoxo‐di‐μ₂‐oxo‐octo­oxo­tetra­molybdate(VI), (C₄H₁₂N)₂[Mo₄O₁₀(OCH₃)₄Cl₂], has been determined from X‐ray diffraction data. The crystallographically centrosymmetric anion is built up of four edge‐sharing octahedra, two MoO₆ and two MoO₅Cl.     

Zur Kenntnis von Cr2H2(As2O7)(As4O12)

The crystal structure of Cr₂H₂(As₂O₇)(As₄O₁₂) has been determined by X-ray methods using single crystal diffractometer data (1,152 reflections,R=0.054, orthorhombic,Pmmn,a=1317.7 (7),b=1124.9 (6),c=494.3 (4) pm,Z=2). The crystal structure contains both diarsenate(V) and the hitherto unknown cyclo-tetraarsenate(V)-anions. The magnetic susceptibility follows theCurie-Weiss law (=3.86±0.01 _B/Cr³⁺, =–31 K).

     

Die Kristallstruktur von Trikobalt(II)-dihydroxidsulfat-dihydrat,Co3(OH)2(SO4)2 · 2 H2O

Tricobalt (II)-dihydroxidesulfate-dihydrate, Co₃(OH)₂(SO₄)₂ · 2H₂O, is orthorhombic: a = 7.21, b = 9.77, c = 12.86 Å, V = 905.9 ų, space group D-Pbcm with four formula units per cell. The atomic positions have been determined by threedimensional Patterson and Fourier synthesis and full-matrix least-squares refinement of single crystal X-ray diffraction data. The structure shows infinite chains [001] of Co? O octahedra sharing one edge with each other. These chains are linked together by alternating SO₄ tetrahedra and additional Co? O octahedra, thus giving rise to a three-dimensional network of polyhedra. There is no similarity to the well known layer structures of most hydroxide salts of divalent metals. The SO₄ tetrahedra are regular while the Co? O octahedra show considerable distortion. The water molecule is coordinated to one Co atom and bonded to sulfate oxygen by two weak hydrogen bridges.     

Die Kristallstruktur des Hexakaliumdigermanats,K6Ge2O7

The title compound is monoclinic, space group Pc (No. 7),a=6.549 (1),b=9.094 (1),c=11.426 (2) Å, =126.78 (1)° andZ=2. Its crystal structure has been refined from 1 323 single crystal X-ray reflections toR=0.131. The structure of K₆Ge₂O₇ is very similar to that of K₆Co₂O₇ and K₆Si₂O₇ both of which have been reported to be centrosymmetric, space group P2₁/c. While the angle at the bridging oxygen atom is 180° in the latter compounds, it is 157° in K₆Ge₂O₇.

     

Crystal structure of a new vanadate variety in the lomonosovite group: Na5Ti2O2[Si2O7](VO4)

The title compound has been prepared by a flux crystallisation method and its crystal structure was determined by single crystal X-ray diffraction: space group P, a=5.309(1), b=7.133(1), c=14.746(2) Å, α=99.05(1), β=95.97(1), γ=90.08(1)°, wR₂=0.073, R=0.028. The structure may be described as built by seidozerite modules of composition Na₂Ti₂O₂Si₂O₇ — brucite-type layers of [TiO₆] and [NaO₆] octahedra embedded between layers of [TiO₆] octahedra, [Si₂O₇] groups and [NaO₈] polyhedra. These almost centrosymmetrical triple-layers alternate along the c-axis with polar double-layer-modules of composition Na₃VO₄ formed by isolated [VO₄]³⁻ anions and six- and four-coordinate Na cations. The crystal structure is discussed in context with minerals of the lomonosovite group. The thermal decomposition behaviour suggests a decay to the single modular components Na₂Ti₂O₂Si₂O₇ and Na₃VO₄.     

Phase Equilibria in the System CuO-Fe2O3-Sb2O4-O2

Results of X-ray phase analysis were used to construct the phase diagram of the system CuO-Fe₂O₃-Sb₂O₄-O₂ at 1000°C in air. Two Cu_2x Fe_4-3x Sb _x O₆ solid solutions (0 x 0.154 and 0.923 x 1) of, respectively, hematite and bixbyite structure were identified.     

Die Kristallstruktur von Ge5O[PO4]6

Zusammenfassung Die Kristallstruktur der Verbindung Ge₅O[PO₄]₆ wurde auf Grund dreidimensionaler Einkristalldaten ausWeissenberg-Aufnahmen ermittelt und nach der Methode der kleinsten Quadrate verfeinert: Raumgruppe ;a=7,994±0,004 undc=24,87±0,01 Å;Z=3; 467 unabhängige Reflexe;R=0,086.Die Kristallstruktur wird aus singulären [GeO₆]-Oktaedern und [Ge₂O₇]-Doppeltetraedern aufgebaut, die über [PO₄]-Tetraeder zu einem dreidimensionalen Strukturverband vernetzt sind. Die mittleren Abstände betragen: Ge^[6]–O=1,863, Ge^[4]–O=1,704 und P–O=1,525 Å.

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The crystal structure of Ge₅O[PO₄]₆

The crystal structure of Ge₅O[PO₄]₆ has been determined and refined by least-squares, using three-dimensional x-ray data fromWeissenberg-photographs: space group ;a=7.994±0.004 andc=24.87±0.01 Å;Z=3; 467 independent reflections;R=0.086.The crystal structure consists of isolated [GeO₆] octahedra and [Ge₂O₇] double tetrahedra which are linked by [PO₄] groups forming a three-dimensional network. The average interatomic distances are: Ge^[6]–O=1.863, Ge^[4]–O=1.704 and P–O=1.525 Å.

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Mit 2 Abbildungen     

Einbau von Al3+ in Ir3O12-Oktaedertripel in Ba4Ir2AlO10

Incorporation of Al³⁺ in Ir₃O₁₂ Octahedra-Triple in Ba₄Ir₂AlO₁₀ Single crystals of Ba₄Ir₂AlO₁₀ were prepared by solid state/flux reactions. It crystallizes with orthorhombic symmetry: space group D–Cmca; a = 5.778; b = 13.352; c = 13.084 Å; Z = 4. The structure is characterized by face connection of three IrO₆- or Ir/AlO₆-octahedra. X-ray investigations show an ordered occupation of the centric octahedron by Ir and a statistically distribution of Ir and Al in the adjacent octahedra. Calculations of the coulomb term of the lattice energy support a charge distribution in the manner Ir⁵⁺/Al³⁺? Ir⁴⁺? Ir⁵⁺/Al³⁺.     

Rb2Co3(H2O)2[B4P6O24(OH)2]: Ein Borophosphat mit ‐Tetraeder‐Anionenteilstruktur und Oktaeder‐Trimeren (CoO12(H2O)2)

Rb₂Co₃(H₂O)₂[B₄P₆O₂₄(OH)₂]: A Borophosphate with ‐Tetrahedral Anionic Partial Structure and Trimers of Octahedra (Co O₁₂(H₂O)₂) Rb₂Co₃(H₂O)₂[B₄P₆O₂₄(OH)₂] is formed under mild hydrothermal conditions (T = 165 °C) from mixtures of RbOH_(aq), CoCl₂, H₃BO₃, and H₃PO₄ (molar ratio 1 : 1 : 1 : 2). The crystal structure (orthorhombic system) was solved by X‐ray single crystal methods (space group Pbca, No. 61; R‐values (all data): R1 = 0.0699, wR2 = 0.0878): a = 950.1(1) pm, b = 1227.2(2) pm, c = 2007.4(2) pm; Z = 4. The anionic partial structure consists of tetrahedral [B₄P₆O₂₄(OH)₂^8–] layers, which contain three‐ and nine‐membered rings. Co^II is octahedrally coordinated by oxygen and oxygen and H₂O ligands, respectively (coordination octahedra CoO₆ and CoO₄(H₂O)₂). Three adjacent coordination octahedra are condensed via common edges to form trimeric units (CoO₁₂(H₂O)₂). The oxidation state +2 of cobalt was confirmed by magnetic measurements. The octahedral trimers are quasi‐isolated. No long‐range magnetic ordering occurs down to 2 K. Rb⁺ is disordered over three crystallographically independent sites within channels of the structure running parallel [010]; the coordination sphere of Rb⁺ is formed by nine oxygen species of the tetrahedral layers, one OH group and one H₂O molecule.     

Sodium magnesium sulfate decahydrate,Na2Mg(SO4)2·10H2O,a new sulfate salt

The structure of synthetic disodium magnesium disulfate decahydrate at 180 K consists of alternating layers of water‐coordinated [Mg(H₂O)₆]²⁺ octahedra and [Na₂(SO₄)₂(H₂O)₄]²⁻ sheets, parallel to [100]. The [Mg(H₂O)₆]²⁺ octahedra are joined to one another by a single hydrogen bond, the other hydrogen bonds being involved in inter‐layer linkage. The Mg²⁺ cation occupies a crystallographic inversion centre. The sodium–sulfate sheets consist of chains of water‐sharing [Na(H₂O)₆]⁺ octahedra along b, which are then connected by sulfate tetrahedra through corner‐sharing. The associated hydrogen bonds are the result of water–sulfate interactions within the sheets themselves. This is believed to be the first structure of a mixed monovalent/divalent cation sulfate decahydrate salt.