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.     

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.     

Die Kristallstrukturen von Tl2AgI3 und NaAgI2 · 3 H2O

Crystal Structure Investigations of Tl₂AgI₃ und NaAgI₂ · 3 H₂O Tl₂AgI₃ was synthesized by the reaction of TlI with AgI in aqueous HI (25%) in a pressure vessel. The compound crystallizes in the rhombohedral space group R3 ; a = 1044,3(2); c = 1993,5(3)pm; Z = 9. The crystal structure contains trinuclear anions [Ag₃I₈]^5? and [ITl₆]⁵⁺ octahedra. The anions are composed of two AgI₄-tetrahedra which are connected to an AgI₆ octahedron via common faces. Single crystals of NaAgI₂ · 3 H₂O were formed by reaction of NaI with AgI in aqueous solution. The compound crystallizes in the orthorhombic space group Pbca with lattice parameters a = 711,2(2); b = 939,8(3); c = 2462,2(4) pm; Z = 8. The crystal structure is built up by polymeric layers [AgI_3/3I_½^1/2?] of corner sharing AgI₄ tetrahedra (GaOCl type) and [Na(H₂O)_4/2(H₂O)I_½^1/2+] octahedra chains.     

Zur Koordination des Aluminiums in den Calciumaluminathydraten 2 CaO · Al2O3 · 8 H2O und CaO · Al2O3 · 10 H2O

On the Coordination of Al in the Calcium Aluminate Hydrates 2 CaO · Al₂O₃ · 8 H₂O and CaO · Al₂O₃ · 10 H₂O By investigations with high-resolution ²⁷Al-NMR in solids it is shown that in the compound 2 CaO · Al₂O₃ · 8 H₂O the Al merely exist in octahedral coordination. According to this and considering its structural relationship with 4 CaO · Al₂O₃ · 19 H₂O the dicalcium aluminate hydrate is proposed to be formulated as [Ca₂Al(OH)₆][Al(OH)₃ (H₂O)₃]OH. Likewise for the compound CaO · Al₂O₃ · 10 H₂O the octahedral coordination of the Al is proved by ²⁷Al-NMR. This result corresponds with literature according to which a constitution as cyclohexaaluminate Ca₃[Al₆(OH)₂₄] · 18 H₂O is proposed.     

NiH3IO6 · 6H2O — Kristallstruktur und Schwingungsspektren

NiH₃IO₆ · 6 H₂O — Crystal Structures and Vibrational Spectra The crystal structure of NiH₃IO₆ · 6 H₂O has been determined by X-ray single-crystal diffraction (Pc, Z = 2, a = 516.74(9), b = 981.5(2), c = 1052.5(2) pm, β = 116.496(8)°) on the basis of 4169 unique reflections (R = 1.96%). The structure is built up of distorted Ni(H₂O)₆²⁺ and H₃IO₆^2? octahedra linked by hydrogen bonding. IR and Raman spectra of both the title compound and isostructural MgH₃IO₆ · 6 H₂O as well as of deuterated specimens are given. There are up to 14 different OH(OD) modes in the spectra of isotopically dilute samples due to the 15 different hydrogen positions of the structure. The internal modes of the meridional H₃IO₆^2? ions (pseudo C_2v symmetry) are discussed with respect to that double T-shaped entity, which gives rise to only two instead of 3I? O, I? O(H), and OH stretches in the IR and Raman spectra, i.e. the same as for facial (C_3v) structured ions.     

Über die Alkaliselenoarsenate(III) KAsSe3 · H2O,RbAsSe3 · 1/2 H2O und CsAsSe3 · 1/2 H2O

On the Alkali Selenoarsenates(III) KAsSe₃ · H₂O, RbAsSe₃ · 1/2 H₂O, and CsAsSe₃ · 1/2 H₂O The alkali selenoarsenates(III) KAsSe₃ · H₂O, RbAsSe₃ · 1/2 H₂O, and CsAsSe₃ · 1/2 H₂O have been prepared by hydrothermal reaction of the respective alkali carbonate with As₂Se₃ at a temperature of 135°C. Their X-ray structural analyses demonstrated that the compounds contain polyselenoarsenate(III) anions (AsSe₃^?)_n, in wich the basic units are ψ-AsSe₃ tetrahedra, which are linked together through Se? Se bonds into infinite zweier single chains. The Rb and Cs salts are isotypic.     

Synthese und Kristallstruktur von Pb2P4O12 · 3 H2O

Synthesis and Crystal Structure Determination of Pb₂P₄O₁₂ · 3 H₂O Pb₂P₄O₁₂ · 3 H₂O precipitates at mixing aqueous solutions of Pb(NO₃)₂ and Na₄P₄O₁₂ (25°C). Crystal growth was achieved by applying gel-techniques (Agar-Agar-gel). The crystal structure (P1 , a = 786.4(3), b = 914.4(3), c = 1021.6(3) pm, α = 97.42(2)°, β = 100.63(2)°, γ = 114.92(2)°; Z = 2; 4160 unique diffractometer data, R = 0.05) contains cyclo-tetraphosphate anions with point symmetry D_2d. Lead is coordinated by eight oxygen, the polyhedra deriving from a square antiprism.     

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.     

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.     

Synthese und Kristallstrukturen von Chlororhenaten(III) mit den zweiwertigen Kationen Ethylendiammonium und Piperazinium:(EnH2)2(Pipzh2)[Re3Cl12]2· 6H2O,und (PipzH2) [Re3Cl12]CI·H2O und (Pipzh2) [Re3Cl11(H2O)]·3H2O

Synthesis and Crystal Structures of Chlororhenates(III) with the Divalent Cations Ethylenediammonium and Piperazinium: (EnH₂)₂(PipzH₂) [Re₃Cl₁₂]₂·6H₂O, (EnH₂) (PipzH₂) [Re₃Cl₁₂]Cl· H₂O, and (PipzH₂) [Re₃Cl₁₁(H₂O)] · 3H₂O The deep red salt (EnH₂)₂(PipzH₂)[Re₃CI₁₂] · 6 H₂O ( 1 ), (EnH₂)(PipzH₂)[Re₃Cl₁₂]CI · H₂O ( 2 ), and (PipzH₂)[Re₃Cl₁₁(H₂O)] · 3H₂O ( 3 ) crystallize upon evaporation from hydrochloride acid solutions of ReCl₃ on addition of ethylenediammonium chloride (EnH₂Cl₂) and/or piperazinium chloride (PipzH₂Cl₂). The crystal structures have been determined from four-circle diffractometer data. 1: monoclinic; a = 1889.63(11), b = 1615.82(8), c = 790.28(4)pm; β = 101.354(5)°; Z = 2; P2₁/n; R = 0.119, R_w = 0.070. 2: triclinic; a = 1330.35(4), b = 1051.14(5), c = 1165.32(6)pm; α = 122.308(4), β = 102.412(3), γ = 92.226(4)°; Z = 2, P1 ; R = 0.092, R_w = 0.059. 3: orthorhombic; a = 971.43(4), b = 1619.51(7), c = 1478.87(6)pm; Z = 4; Pbcm; R = 0.034, R_w = 0.032.     

Röntgenographische und spektroskopische Untersuchungen an Ba2Ni(N3)6· 3H2O

Preparation and X-Ray Examination of Ba₂Ni(N₃)₆ · 3 H₂O Ba₂Ni(N₃)₆ · 3 H₂O has been prepared by the reaction of an aqueous solution of Ba(N₃)₂ with basic nickel azide. The crystals are green, the lattice constants are: a = 7.09 Å, b = 7.09 Å, c = 16.30 Å, α = 74.58°, β = 105.42°, γ = 97.10°, N = 2. Optical spectra point to an octahedral microsymmetry of the azide ions around nickel.     

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.     

Darstellung und röntgenographische Untersuchung des Zinkazidtrihydrates Zn(N3)2 · 3 H2O

Preparation and X-ray Investigation of Zinc Azide Trihydrate Zn(N₃)₂ · 3 H₂O has been crystallized from an aqueous solution of zinc azide. Single crystals, which are unstable in air, were investigated my means of x-ray techniques. The lattice parameters are: a = 9.95 Å, b = 5.94 Å, c = 14,30 Å, β = 134.55°, N = 4. Indexd powder pattern are listed.     

Barium chlorite hydrate,Ba(ClO2)2·3.5H2O

The structure of barium chlorite hydrate, Ba(ClO₂)₂·3.5H₂O, has been determined by single‐crystal X‐ray analysis at 150 K. The structure is monoclinic, space group C2/c, with Z = 8. It contains layers of Ba²⁺ cations coordinated by ClO₂⁻ anions and water mol­ecules. There are also solvate water mol­ecules involved only in hydrogen bonding of the layers. Three solvate water O atoms are on sites of twofold symmetry, while all other atoms are in general positions. The full coordination environment of the Ba²⁺ cation consists of ten O atoms belonging to six chlorites and three water mol­ecules, forming a bicapped square antiprism.     

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.     

Die Kristallstruktur des SrHg(SCN)4 · 3 H2O

Crystal Structure of SrHg(SCN)₄ · 3 H₂O SrHg(SCN)₄ · 3 H₂O is orthorhombic, space group Pcca, with a = 19.476(7), b = 8.150(1), c = 8.991(3) Å, V = 1427.1 ų, Z = 4, d_c = 2.67 g · cm^?3, μ(AgKα) = 77.95 cm^?1. The salt consists of nearly tetrahedral Hg(SCN)₄ groups, Sr has a tricapped trigonal prismatic coordination: four N and five O atoms. The thiocyanate groups form end-to-end bridges and connect the Hg and Sr coordination polyhedra.     

Darstellung und Kristallstrukturen von tBu‐substituierten Disiloxanen des Typus tBu2SiX‐O‐SiYtBu2 (X = Y = OH,Br; X = OH,Y = H) und den Addukten tBu3SiOH·(HO3SCF3)0.5·H2O und tBu3SiOLi·(LiO3SCF3)2·(H2O)2

Syntheses and Crystal Structures of tBu‐substituted Disiloxanes tBu₂SiX‐O‐SiYtBu₂ (X = Y = OH, Br; X = OH, Y = H) and of the Adducts tBu₃SiOH·(HO₃SCF₃)_0.5·H₂O and tBu₃SiOLi·(LiO₃SCF₃)₂·(H₂O)₂ The disiloxanes tBu₂SiX‐O‐SiYtBu₂ (X = Y = H, OH) are accessible from the reaction of CF₃SO₂Cl with tBu₂SiHOH or tBu₂Si(OH)₂. By this reaction the disiloxane tBu₂SiH‐O‐SiHtBu₂ is formed together with tBu₂SiH‐O‐SiOHtBu₂. The disiloxanes tBu₂SiX‐O‐SiYtBu₂ (X = Y = Cl, Br) can be synthesized almost quantitatively from tBu₂SiH‐O‐SiHtBu₂ with Cl₂ and Br₂ in CH₂Cl₂. The structures of the disiloxanes tBu₂SiX‐O‐SiYtBu₂ (X = H, Y = OH; X = Y = OH, Br) show almost linear Si‐O‐Si units with short Si‐O bonds. Single crystals of the adducts tBu₃SiOH·(HO₃SCF₃)_0.5·H₂O and tBu₃SiOLi·(LiO₃SCF₃)₂·(H₂O)₂ have been obtained from the reaction of tBu₃SiOH with CF₃SO₃H and of tBu₃SiO₃SCF₃ with LiOH. According to the result of the X‐ray structural analysis (hexagonal, P‐62c), tBu₃SiOLi · (LiO₃SCF₃)₂·(H₂O)₂ features the ion pair [(tBu₃SiOLi)₂(LiO₃SCF₃)₃(H₂O)₃Li]⁺ [CF₃SO₃]^?. The central framework of the cation forms a trigonal Li₆ prism.     

Crystal Structure of a Cadmium Iodate Monohydrate: Cd(IO3)2·H2O

Single crystals of Cd(IO₃)₂·H₂O are obtained by slow evaporation of aqueous solutions of CdCl₂ and KIO₃. This compound crystallizes in the triclinic space group P1¯ [a = 7.119(2), b = 7.952(2), c = 6.646(2)Å, α = 102.17(2)°, β = 114.13(2)°, γ = 66.78(4)°]. The structure consists in Cd — (μ2‐O)₂ — Cd dimers with a metal — metal distance of 3.74Å. These dimers are connected through two iodate bridges resulting in layers parallel to the (010) plane. The 3D linkage is ensured by I1 — O1 long bonds (2.775Å).     

Die Kristallstruktur des Zn(N3)2 · 2,5 H2O

Crystal Structure of Zn(N₃)₂ · 2.5 H₂O The crystal structure of zinc azide 2.5 hydrate, 1975 erroneously described as a trihydrate, was determined by single crystal x-ray diffraction. The crystals are monoclinic, a = 996.2(5), b = 594.8(5), c = 1018.4(9) pm, β 90.16(3)°, space group P2/n, Z = 4, R = 0.043. Zinc is hexacoordinated by four azide groups and two water molecules. The octahedra around zinc share nitrogen atoms as common edges and they are connected to form strings along the b-axis. The water molecules are arranged to chainlike clusters, two of the ten water molecules are not coordinated to zinc. The azide groups are asymmetric and almost linear.