Zur Struktur eines ungewöhnlichen Tetramers des Lithiumphenolats: [C6H5OLi · C4H8O]4 · C6H5OH

The Structure of an unusual Tetramere of Lithium Phenoxide: [C₆H₅OLi · C₄H₈O]₄ · C₆H₅OH Single crystals of lithium phenoxide have been obtained from THF. In the structure (P 2₁/n, Z = 4, a = 11.69 Å, b = 21.15 Å, c = 18.55 Å, β = 91.11°) four lithium atoms and four phenoxide oxygen atoms are cubically arranged. Further, each lithium atom coordinates the oxygen atom of a tetrahydrofuran molecule. The ideal cubeform structure is disturbed by one phenol molecule which is coordinated in addition to four phenoxide and four THF molecules. Hence, one edge of the cube (Li4? O4) is substituted by the coordination of the phenol oxygen atom O5 with Li4 and hydrogen bonding between O4 and the hydroxy group of phenol. Van der Waals forces are the only interaction between these complexes.     

Kristallstrukturbestimmung von NaHC2O4 · H2O

NaHC₂O₄ · H₂O crystallizes in space group P 1 with a₀ = 6,51, b₀ = 6,66, c₀ = 5,70 Å, α₀ = 95,0°, β₀ = 109,8°, γ₀ = 74,9° and Z = 2. The structure was solved by direct methods. The refinement was carried out with 679 reflections to R₁ = 7,7%. The angle between the O? C? O planes is 12,6°.     

Einkristallzüchtung und Röntgenstrukturanalyse von CoSO4 · Pyrazin · 6 H2O (I) und (CoSO4)2 · Pyrazin · 12 H2O (II)

Crystal Growth and Structure of CoSO₄ · Pyrazine · 6 H₂O (I) and (CoSO₄)₂ · Pyrazine · 12 H₂O (II) Single crystals of μ-pyrazino-bis[pentaquacobalt(II)]-sulfate-dihydrate CoSO₄(pz) · 6 H₂O and Tetraqua-μ-pyrazino-cobalt(II)sulfate-dihydrate (CoSO₄)₂(pz) · 12 H₂O were grown by using gel methods and investigated by X-ray analysis. CoSO₄(pz) · 6 H₂O (I) shows monoclinic symmetry, space group C2/c; a = 1006.4(4) pm, b = 1026.9(4) pm, c = 1261.5(2) pm; β = 104.01(4)°; Z = 4. (CoSO₄)₂(pz) · 12 H₂O (II) shows orthorhombic symmetry, space group Pbam; a = 1262.3(4) pm, b = 1231.3(4) pm, c = 684.1(2) pm; Z = 2. CoSO₄ and Pyrazine crystallize in a polymeric (I) as well as in a dimeric (II) compound. In the polymeric compound the molecules are bonded by pyrazine to form alternating linear chains. The dimer is a dinuclear complex with a bridging pyrazine molecule.     

[VO(SeO3)(H2O)2]·0.5H2O

In poly[[diaquaoxido[μ₃‐trioxidoselenato(2−)]vanadium(IV)] hemihydrate], {[VO(SeO₃)(H₂O)₂]·0.5H₂O}_n, the octahedral V(H₂O)₂O₄ and pyramidal SeO₃ building units are linked by V—O—Se bonds to generate ladder‐like chains propagating along the [010] direction. A network of O—H...O hydrogen bonds helps to consolidate the structure. The O atom of the uncoordinated water molecule lies on a crystallographic twofold axis. The title compound has a similar structure to those of the reported phases [VO(OH)(H₂O)(SeO₃)]₄·2H₂O and VO(H₂O)₂(HPO₄)·2H₂O.     

Hydrate schwacher und starker Basen. XI. Die Kristallstrukturen von NaOH · 3,5H2O und NaOH · 7 H2O. Eine Präzisierung

Hydrates of Weak and Strong Bases. XI. The Crystal Structures of NaOH · 3,5H₂O and NaOH · 7 H₂O. A Refinement The crystal structures of the hydrates NaOH · 3,5 H₂O (space group P2₁/c, Z = 8 formula units per unit cell; lattice parameters: a = 6.481, b = 12.460, c = 11.681 Å, β = 104.12° at ?100°C) and NaOH · 7 H₂O (P2₁/c, Z = 4; a = 7.344, b = 16.356, c = 6.897 Å, β = 92.91° at ?150°C) have been redetermined using MoKα diffractometer data. The obtained refinement of the structures, including the localization also of the H atoms for the first time, has led to new findings with respect to the H bonds. In particular, in both hydrates there is one such interaction of the rare type OH^? …? OH₂, from an OH^? ion to an H₂O molecule, i. e. with the OH^? ion as the proton donor.     

Crystal chemistry of MX · MgX2 · 6H2O type compounds

The following MX · MgX₂ · 6H₂O compounds (double salt hexahydrates) were synthesized by variation of the M⁺ and X^? ions: CsCl · MgCl₂ · 6 H₂O, Li(H₂O)Cl · MgCl₂ · 6H₂O, NH₄Br · MgBr₂ · 6 H₂O, RbBr · MgBr₂ · 6 H₂O, CsBr. MgBr₂ · 6 H₂O, KI · MgI₂ · 6 H₂O, NH₄I. Mgl₂ · 6 H₂O and RbI · MgI₂ · 6H₂O. By X-ray analysis of powder samples the lattice parameters and the space group were determined. On the basis of the results thus obtained, an identification with structural types was carried out. In accordance with the findings, the structure is made up of (M⁺)X₆^?octahedra which are linked into perovskite type units by sharing vertices. Their interstices are occupied by the Mg(H₂O)₆²⁺ octahedra. A “tolerance factor” t which has been calculated on the basis of the proportion of radii and which attains values between 1.045 and 1.061 is a criterion for the upper limit of the area of existence of this structure. Carnallite has a higher to value and, therefore, a different structure.     

Study on the System CoSeO4?NiSeO4?H2O at 30°C Crystal Structure of CoSeO4 · 5 H2O

A study of the system CoSeO₄? NiSeO₄? H₂O at 30°C has been carried out. Crystals were obtained by slow evaporation from a water solution. The identified phases were CoSeO₄ · 5 H₂O and NiSeO₄ · 6 H₂O, but CoSeO₄ · 6 H₂O is identified when the crystallization of Co compound is carried out in presence of Ni. The three phases show a limited replacement of metal according to X-ray powder results. The crystal structure of CoSeO₄ · 5 H₂O has been solved, the come pound is triclinic, a = 6.435(1), b = 10.703(2), c = 6.220(1) Å, α = 98.71(1), β = 109.60(2), γ = 75.54(1)°, P1 , Z = 2. Refinement was terminated at R = 0.035 for all observed reflections. The crystal structure is isostructural to CuSO₄ · 5 H₂O and consists of Co(H₂O)₄ ions chains parallel to [11 0] μ-linked by the SeO₄. The fifth water molecule acts as buffer.     

Hydrate schwacher und starker Basen. VII. Zum System Caesiumhydroxid-Wasser: Die Kristallstrukturen von CsOH · 2H2O und CsOH · 3H2O

Hydrates of Weak and Strong Bases. VII. Concerning the System Cesium Hydroxide—Water: The Crystal Structures of CsOH · 2H₂O and CsOH · 3H₂O In the context of structural studies of hydrates of the alkali metal hydroxide the crystal structure of CsOH · 2H₂O and CsOH · 3H₂O have been determined for the first time. The diffractometer data, obtained at -150 · C,made it possible to locate and refine also all the H-atoms. The dihydrate was found to probably form only one phase, melting incongruently at 2,5 · C. It is orthorhombic with space group Pca2₁ and Z = 8 formula units per unit cell. The lattice constants are a = 13.238, b = 6.747 and c = 9.121 A. With 1870 independent observed reflection a final R value of 0.013 was obtained. The trihydrate, melting congruently et -5.5 ·C, is monoclinic with space group P2₁/n,Z = 4 and lattice constants a = 8.637, b = 5.984, c = 10.061 Å and ß = 96.57 ·. With 2098 independent observed reflection the final R is 0.026. In both hydrate structures there are no simple characteristic coordination polyhedra for the cations; in each case it is rather the hydrogen-bonded and fully ordered anionic water structure which shows up as the determining building principle. Both these water structures are altogether three-dimensional, but primarily contain layers. The anionic layers are formed by condensation of small and medium rings, namely four-, five- and seven-membered rings in CsOH · 2H₂O and four-, five- and six membered ones in CsOH · 3H₂O. They are linked together by one set each of extra H₂O molecules between the layers as well as by the Cs⁺ ions.     

Erdalkali-Fluoromanganate(III): BaMnF5 · H2O und SrMnF5 · H2O

Alkaline Earth Fluoromanganates(III): BaMnF₅ · H₂O and SrMnF₅ · H₂O Solid BaF₂ or SrF₂ forms with solutions of Mn³⁺ in aqueous hydrofluoric acid precipitates of hitherto unknown BaMnF₅ · H₂ and SrMnF₅ · H₂O respectively. X-ray structure determination on single crystals of both isotypic compounds (space group P2₁/m, Z = 2; BaMnF₅ · H₂O: a = 537.0(3), b = 817.2(2), c = 628.0(4) pm β = 111.17(5)°, R_w = 0.035 for 1403 reflections; SrMnF₅ · H₂O: a = 510.8(1), b = 792.0(2), c = 610.6(1) pm, β = 110.24(1)° R_w = 0.068 for 539 reflections) reveal pure [MnF₆]^3? octahedra connected with each other to infinite chains by sharing trans corners. The H₂O molecules are coordinated to the alkaline earth ions only and form weak O? H…F hydrogen bonds. The pronounced weakening of the Mn? F bonds within the chain direction (Mn? F 2X 212.7(1)/210.8(5) pm, 2X 183.8(3)/181.8(9) pm, 2X 186.9(2)/187.2(8) pm) may be due by halves to the Jahn-Teller-effect as can be deduced by bond valence calculations.     

Die Kristallstruktur des Bleicyclotetraphosphat-4-Hydrats,Pb2P4O12 · 4H2O

Crystal Structure of Lead Cyclotetraphosphate-4-Hydrate, Pb₂P₄O₁₂·4 H₂O Pb₂P₄O₁₂·4 H₂O is the starting product of a series of solid state reactions with the final product cyclooctaphosphate. Pb₂P₄O₁₂·4 H₂O crystallizes in the monoclinic space group P2₁/n, with a = 8.07 ± 0.02, b = 11.76 ± 0.03, c = 7.50 ± 0.02 Å and β = 108.2 ± 0.3°. The crystal structure has been solved by Patterson and Fourier methods and refined by least squares calculations to an R-index of 0.07. The structure consists of P₄0₁₂^4? ringanions, which are connected by Pb and hydrogen bonds. Lead is coordinated by eight oxygen atoms.     

Zu den Kristallstrukturen der Übergangsmetall(II)‐Dodekahydro‐closo‐Dodekaborat‐Hydrate Cu(H2O)5,5[B12H12]·2,5 H2O und Zn(H2O)6[B12H12]·6 H2O

On the Crystal Structures of the Transition‐Metal(II) Dodecahydro‐closo‐Dodecaborate Hydrates Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O and Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O By neutralization of an aqueous solution of the free acid (H₃O)₂[B₁₂H₁₂] with basic copper(II) carbonate or zinc carbonate, blue lath‐shaped single crystals of the octahydrate Cu[B₁₂H₁₂]·8 H₂O (≡ Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O) and colourless face‐rich single crystals of the dodecahydrate Zn[B₁₂H₁₂]·12 H₂O (≡ Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O) could be isolated after isothermic evaporation. Copper(II) dodecahydro‐closo‐dodecaborate octahydrate crystallizes at room temperature in the monoclinic system with the non‐centrosymmetric space group Pm (Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O: a = 768.23(5), b = 1434.48(9), c = 777.31(5) pm, β = 90.894(6)°; Z = 2), whereas zinc dodecahydro‐closo‐dodecaborate dodecahydrate crystallizes cubic in the likewise non‐centrosymmetric space group F23 (Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O: a = 1637.43(9) pm; Z = 8). The crystal structure of Cu(H₂O)_5.5[B₁₂H₁₂]·2.5 H₂O can be described as a monoclinic distortion variant of the CsCl‐type arrangement. As characteristic feature the formation of isolated [Cu₂(H₂O)₁₁]⁴⁺ units as a condensate of two corner‐linked Jahn‐Teller distorted [Cu(H₂O)₆]²⁺ octahedra via an oxygen atom of crystal water can be considered. Since “zeolitic” water of hydratation is also present, obviously both classical H–O^δ?···^+δH–O and non‐classical B–H^δ?···^+δH–O hydrogen bonds play a significant role for the stabilization of the structure. A direct coordinative influence of the quasi‐icosahedral [B₁₂H₁₂]^2? anions on the Cu²⁺ cations has not been determined. The zinc compound Zn(H₂O)₆[B₁₂H₁₂]·6 H₂O crystallizes in a NaTl‐type related structure. Two crystallographically different [Zn(H₂O)₆]²⁺ octahedra are present, which only differ in their relative orientation within the packing of the [B₁₂H₁₂]^2? anions. The stabilization of the crystal structure takes place mainly via H–O^δ?···^+δH–O hydrogen bonds, since again the hydrogen atoms of the [B₁₂H₁₂]^2? anions have no direct coordinative influence on the Zn²⁺ cations.     

Die Kristallstrukturen von K8Ta6O19 · 16H2O und K7NaTa6O19 · 14H2O

The Crystal Structures of K₈Ta₆O₁₉ · 16H₂O and K₇NaTa₆O₁₉ · 14H₂O By alkaline digestion of Ta₂O₅ with p.a. KOH transparent single crystals of the composition K₈Ta₆O₁₉ · 16H₂O are formed. When technical grade KOH is used, the same kind of synthesis yields crystals of the composition K₇NaTa₆O₁₉ · 14H₂O. The latter compound has been given the formula K₈Ta₆O₁₉ · 14H₂O until now. In both cases the isopolyoxoanion [Ta₆O₁₉]⁸ consists of six TaO₆-octahedra connected by edge sharing. This means that the heavy atom partial structure found by Lindquist et al. is confirmed. Additionally the complete structures including the atomic positions of the oxygen atoms of the polyanions as well as those of the cations and crystal water molecules (without hydrogen positions) are determined.     

Zur Kenntnis der Hydrate des Typs MX2 · 1 H2O mit M = Sr,Ba und X = Cl,Br, I. Kristallstrukturen des Strontiumchlorid-Monohydrats,SrCl2 · 1 H2O,und des Strontiumbromid-Monohydrats,SrBr2 · 1 H2O

On Hydrates of the Type MX₂ · 1 H₂O with M = Sr, Ba and X = Cl, Br, I. Crystal Structures of Strontium Chloride Monohydrate, SrCl₂ · 1 H₂O, and Strontium Bromide Monohydrate, SrBr₂ · 1 H₂O The structures of SrCl₂ · 1 H₂O, orthorhombic, Pnma, a = 1088.1(1), b = 416.2(1), c = 886.4(1) pm, Z = 4, d_c = 2.92 Mg m^?3, R = 0.052 for 755 reflections, and of SrBr₂ · 1 H₂O, orthorhombic, Pnma, a = 1146.4(1), b = 429,5(1), c = 922.9(1) pm, Z = 4, d_c = 3.88 Mg m^?3, R = 0.056 for 762 reflections have been determined from a Patterson synthesis and refined by Fourier and Least Squares methods. The structure consists of [SrX₂ = H₂O]_n-layers normal to [100] and Sr? H₂O? Sr? H₂O-chains parallel [010]. The Sr? O distances are 265.1(3) pm, SrCl₂ · 1 H₂O, and 265.9(4) pm, SrBr₂ · 1 H₂O. The shortest Sr? Cl and Sr? Br distances (298.9(1) and 315.3(1) pm) are within the layers. The environment of oxygen and strontium is a distorted tricapped trigonal prism. The orientation of the water molecules has been determined from vibrational spectroscopic measurements. The hydrogen atoms H₁ and H₂ form bifurcated hydrogen bonds of different strength to neighbouring halide ions. The corresponding O···X distances are 331.9(4) and 320.2(4) pm, SrCl₂ · 1 H₂O, and 340.8(4) and 333.8(4) pm, SrBr₂ · 1 H₂O. The other O? X distances are between 310.3(5) and 323.7(5) pm, SrCl₂ · 1 H₂O, and 323.5(5) and 333.2(6) pm, SrBr₂ · 1 H₂O.     

KHCoP2O7·2H2O: a novel acidic pyrophosphate

Potassium cobalt hydrogenpyrophosphate dihydrate, KHCoP₂O₇·2H₂O, crystallizes in the orthorhombic space group Pnma. This salt is isotypic with KHMP₂O₇·2H₂O (M = Mn and Zn). The structure consists of alternating layers, built from HP₂O₇³⁻ acidic pyrophosphate groups and CoO₆ octahedra, joined by potassium ions and bridging hydrogen bonds. The Co, K and water O atoms lie on mirror planes. The pyrophosphate group consists of two symmetry‐related PO₄ groups, with the bridging O atom on a mirror plane.     

Zur Kristallstruktur von CaZn2(OH)6 · 2 H2O

Crystal Structure of CaZn₂(OH)₆ · 2 H₂O The electrochemical oxidation of zinc in a zinc/iron-pair leads in an aqueous NH₃ solution of calciumhydroxide at room temperature to colourless crystals of CaZn₂(OH)₆ · 2 H₂O. The X-ray structure determination was now successful including all hydrogen positions. P2₁/c, Z = 2, a = 6.372(1) Å, b = 10.940(2) Å, c = 5.749(2) Å, β = 101.94(2)° N(F ≥ 3σF) = 809, N(Var.) = 69, R/R_W = 0.011/0.012 The compound CaZn₂(OH)₆ · 2H₂O contains Zn²⁺ in tetrahedral coordination by OH^? and Ca²⁺ in octahedral coordination by four OH^? and two H₂O. The tetrahedra around Zn²⁺ form corner sharing chains, three-dimensionally linked by isolated polyhedra around Ca²⁺. Weak hydrogen bridge bonds result between H₂O as donor and OH^?.     

Röntgenographische Kristallstrukturuntersuchung von Magnesiumperrhenat-tetrahydrat Mg(ReO4)2 · 4 H2O

Crystal Structure of Magnesium Perrhenate Tetrahydrate Mg(ReO₄)₂ · 4 H₂O The crystal structure of Mg(ReO₄)₂ · 4 H₂O was determined from single-crystal X-ray diffractometer data. The compound is triclinic, space group P1, with lattice parameters a = 769.2, b = 702.6, c = 646.9 pm, α = 108.279, β = 92.388, γ = 120.418°, Z = 1, ?_calcd. = 3.58 g · cm^?3, ?_exp. = 3.62 g · cm^?3. The structure was solved in anisotropic approximation from 2990 observed reflections and refined to an index R of 7.4%. The rhenium atom is tetrahedrally, the magnesium atom octahedrally coordinated.     

Kristallstrukturen des Sr(OH)2 · H2O,Ba(OH)2 · H2O (o.-rh. und mon.) und Ba(OH)2 · 3 H2O

Crystal Structures of Sr(OH)₂ · H₂O, Ba(OH)₂ · H₂O (o.-rh. and mon.), and Ba(OH)₂ · 3 H₂O The crystal structures of Ba(OH)₂ · 3 H₂O (Pnma, Z = 4), γ-Ba(OH)₂ · H₂O (P2₁/m, Z = 2) and the isotypic Sr(OH)₂ · H₂O and β-Ba(OH)₂ · H₂O (Pmc2₁, Z = 2) were determined using X-ray single crystal data. Ba(OH)₂ · 3 H₂O and Ba(OH)₂ · H₂O mon. crystallize in hitherto unknown structure types. The structure of Ba(OH)₂ · H₂O mon. is strongly related to that of rare earth hydroxides M(OH)₃ with space group P6₃/m (super group of P2₁/m). The metal-oxygen distances are significantly shorter for OH^? ions (mean Ba—O bond lengths of all hydroxides under investigation 278.1 pm) than for H₂O molecules (289.9 pm). Corresponding to other hydrates of ionic hydroxides, the water molecules form strong hydrogen bonds to adjacent OH^? ions whereas the hydroxide are not H-bonded.     

Die Kristallstruktur von VO2JO3·2H 2O

The Crystal Structure of VO₂IO₃·2 H₂O VO₂IO₃ possesses a layer structure and crystallizes in the space group P2₁/c with a = 9.848(3) Å, b = 8.l58(2) Å, c = 7.192(2) Å, β = 102.17(2)° and four formula units in the unit cell. The individual layers of the structure consist of highly distorted corner- and edgesharing IO₆, and VO₆, octahedra. Only one oxygen atom is bound terminally at the vanadium, as is shown by the vibrational spectrum, too.     

Zur Kristallstruktur von SrZn(OH)4 · H2O

Crystal Structure of SrZn(OH)₄ · H₂O Colorless crystals of SrZn(OH)₄ · H₂O are obtained by electrochemical oxidation of Zn in a zinc/iron pair in an aqueous ammonia solution saturated with strontium hydroxide. The X-ray crystal structure determination was now successful including all hydrogen positions: P1 , Z = 2, a = 6.244(1) Å, b = 6.3000(8) Å, c = 7.701(1) Å, α = 90.59(1)°, β = 112.56(2)°, γ = 108.66(2)°, N(F ≥ 3σF) = 1967, N(Var.) = 84, R/R_w = 0.020/0.024. In SrZn(OH)₄ · H₂O Zn²⁺ is tetrahedrally coordinated by four OH^? -ions while Sr²⁺ has 6 OH^? and one H₂O as neighbours. The polyhedra around Sr²⁺ are connected to chains which are linked three-dimensionally by isolated tetrahedra [Zn(OH)₄]. Hydrogen bonds between H₂O as donor and OH^? are characterized by raman spectroscopy.     

Fluorenyl Zinc Phosphonate Zn(H2O)PO3–C13H9·H2O: Hybrid Columnar Structure with Strong C–H···π Interactions

A new zinc phosphonate Zn(H₂O)PO₃–C₁₃H₉ · H₂O with a columnar structure was synthesized in hydrothermal conditions. This compound crystallizes in space group P2₁/c [a = 15.832(4) Å, b = 5.1915(10) Å, c = 17.519(4) Å and β = 114.479(6)°]. Its inorganic framework consists of isolated chains of corner‐sharing ZnO₃(H₂O) and PO₃C tetrahedra. These chains are linked to fluorene cycles, forming hybrid columns, interconnected through C–H ··· π bonds. The photoluminescence properties of this hybrid material show that its emission bands are red shifted with respect to those of the mother phosphonic acid. This effect is explained on the basis of the structural constraints imposed by the inorganic Zn‐phosphonate chains.