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.     

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 Bariumchlorids. Röntgenographische,thermoanalytische, Raman- und IR-spektroskopische Untersuchungen

Hydrates of Barium Chloride. X-ray, Thermoanalytical, Raman, and I.R. Data In the system BaCl₂? H₂O the hydrates BaCl₂ · 2 H₂O, BaCl₂ · 1 H₂O, BaCl₂ · 1/2 H₂O, and BaCl₂ · uH₂O were obtained. X-ray powder data, i.r. and Raman spectra, as well as thermoanalytical measurements (TG, DTA) are reported. BaCl₂ · 1 H₂O and BaCl₂ · 1/2 H₂O, which are both isotype with the corresponding hydrates of SrCl₂, were prepared by dehydration of BaCl₂ · 2 H₂O or by back hydration of anhydrous BaCl₂ with the calculated amounts of water. BaCl₂ · uH₂O (u ≈? 1) is formed as the primary product by the reaction of anhydrous BaCl₂ with water vapour at room temperature. Preparation methods of salt hydrates by controlled back hydration of the anhydrous salts are reported.     

The kinetic study of thermal dehydration stages of SrCl2 · 2H2O and its deuterium analog

The kinetic deuterium isotope effect in the thermal dehydration stages of powdered SrCl₂ · 2H₂O was examined by means of both isothermal and dynamic gravimetries. These dehydration processes proved to be controlled by a random nucleation and its subsequent growth mechanism. No significant kinetic isotope effect was seen in these dehydration stages. It seems that there exists a kinetic compensation effect between the hydrate and its deuterium analog, if any isotopic differences in activation energy and frequency factor could exist.     

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.     

Zur Kenntnis der Phase BaO · Al2O3 · 7 H2O

On the Compound BaO · Al₂O₃ · 7 H₂O On the basis of investigations using ²⁷Al, ¹H NMR, IR and thermoanalytical methods for the compound BaO · Al₂O₃ · 7 H₂O a constitution as Ba_n[Al₂(OH)₈]_n · 3n H₂O with condensed AlO₆ groups, sharing edges, is proposed. Relations between the Ba/Al ratio and the constitution of anions of barium aluminate hydrates are discussed.     

Kristallstrukturen des Sr(BrO3)2 · H2O,Ba(BrO3)2 · H2O,Ba(IO3)2 · H2O,Pb(CIO3)2 · H2O und Pb(BrO3)2 · H2O

Crystal Structure of Sr(BrO₃)₂ · H₂O, Ba(BrO₃)₂ · H₂O, Ba(IO₃)₂ · H₂O, Pb(ClO₃)₂ · H₂O, and Pb(BrO₃)₂ · H₂O The crystall structures of the isostructural halates Sr(BrO₃)₂ · H₂O, Ba(BrO₃)₂ · H₂O, Ba(IO₃)₂ · H₂O, Pb(ClO₃)₂ · H₂O, and Pb(BrO₃)₂ · H₂O were determined using X-ray single crystal data (monoclinic space group C2/c? C, Z = 4), The mean bond lengths and bond angles of the halate ions in the Ba(ClO₃)₂ · 1 H₂O-type compounds, which correspond to those of other halates, are Cl? O, 149.0, Br? O, 165.9, I? O, 180.2 pm, ClO₃^?, 106.4, BrO₃^?, 104.0, and IO₃^?, 99.6°. The structure data obtained are discussed in terms of possible orientational disorder of the water molecules, strengths of the hydrogen bonds, influence of the lead ions on the structure, and site group distortion of the halate 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.     

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.     

New Fluoromanganate(III) Hydrates: Mn3F8 · 12H2O and AgMnF4 · 4H2O

Single crystals of fluoride hydrates Mn₃F₈ · 12 H₂O and AgMnF₄ · 4 H₂O have been prepared and characterized by X-ray methods. Mn₃F₈ · 12 H₂O crystallizes in the space group P1 (a = 623.0(3), b = 896.7(4), c = 931.8(4) pm, α = 110.07(2)°, β = 103.18(2)°, γ = 107.54(2)°, Z = 1); AgMnF₄ · 4 H₂O crystallizes in the space group P2₁/m (a = 700.9(2), b = 726.1(1), c = 749.4(3) pm, β = 107.17(3)°, Z = 2). Both structures contain Jahn-Teller-distorted [Mn(H₂O)₂F₄]^? anions as well as crystal water molecules and exhibit a complex hydrogen bond network between anions and cations, i. e. [Mn(H₂O)₆]²⁺ for the first and a polymeric [Ag(H₂O)₂]^? cation for the second compound.     

Magnesiumiodatdecahydrat Mg(IO3)2 · 10 H2O – Kristallstruktur,Ramanspektren, thermischer Abbau,lone-pair-Radius von Iod(V)

Magnesium Iodate Decahydrate Mg(IO₃)₂ · 10 H₂O – Crystal Structure, Raman Spectra, Thermal Decomposition, Lone-Pair Radius of Iodine(V) Mg(IO₃)₂ · 10 H₂O crystallizes in the triclinic space group P1 (a = 654.25(9), b = 1109.8(2), c = 1176.7(2) pm; α = 105.470(8), β = 104.086(8), γ = 101.744(8)°; Z = 2). The structure has been determined by single-crystal X-ray diffraction at 273 K, and refined to a final R value of 0.0272 for 4372 observed reflections (I > 2σ(I)). The magnesium ions are coordinated to six different H₂O molecules forming a slightly distorted octahedron with Mg? O distances varying between 202.2(2) and 211.6(3) pm. The hexaaquamagnesium ions are arranged parallel to (010). The two kinds of iodate ions and the four different “free” water molecules are filled between the layers thus formed. There are twenty independent hydrogen bonds with O … O distances from 268.7(3) to 287.6(4) pm. On the basis of all intermolecular I … I distances of iodates reported in the literature, 180 pm are recommended as van-der-Waals radius resp. lonepair radius of iodine(V). DSC and Raman spectroscopic experiments as well as high-temperature Raman and X-ray measurements were performed and are discussed with respect to the energetic and geometric distortion of the IO₃^? ions and the dehydration of the decahydrate via the tetrahydrate (308 K) to Mg(IO₃)₂ (428 K).     

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.     

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.     

Zur Polymorphie und Pseudosymmetrie der Hydrate MSeO3 · H2O (M = Mn,Co, Ni,Zn, Cd)

Polymorphic and Pseudosymmetrical Hydrates MSeO₃ · H₂O (M = Mn, Co, Ni, Zn, Cd) By crystallization from aqueous solutions of MSeO₃ and M(HSeO₃)₂, the selenites MSeO₃ · H₂O (M = Mn, Co, Ni, Zn, Cd) were obtained and characterized by means of X-ray diffraction and IR-spectroscopy. The crystal structure of ZnSeO₃ · H₂O was determined. The IR spectra indicate that the hydrates are isotypic and contain H₂O molecules of symmetry mm2. However, the X-ray data show different structure types with H₂O molecules of site symmetry m or 1. CdSeO₃ · H₂O and MnSeO₃ · H₂O are isotypic (o.rh., MnSeO₃ · D₂O type). CoSeO₃ · H₂O (mon.) as well as the isotypic NiSeO₃ · H₂O and ZnSeO₃ · H₂O (mon.) form new structure types. These findings are discussed on the basis of the crystal structure of ZnSeO₃ · H₂O (P2₁/n, a = 477.9(1), b = 1319.4(5), c = 570.1(1) pm, β = 90.84(2)°, Z = 4, D_x = 3.886 g · cm^?3, R = 0.035 for 722 reflections with I > 2σ₁) and the local pseudosymmetry of its components, i.e., layers [ZnSeO₃ · H₂O] of ZnO₆ octahedra sharing four equatorial vertices, SeO₃^2? anions and H₂O molecules.     

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.     

Synthesis, Characterization and Thermochemistry of 2MgO：B2O3：1.5H2O

Introduction　　 2MgO·B2 O3(Mg2 B2 O5)and 2MgO·B2 O3·H2 Omightbepreparedaswhiskermaterials .12MgO·B2 O3·H2 OnamedszaibelyiteisamagnesiumboratemineralwithastructuralformulaofMg2 [B2 O4 (OH) 2 ].2 Itisdifficulttosynthesizethiscompoundinthelaboratory .Recently ,weobtainedasimilarcompound 2MgO·B2 O3·1 5H2 Owhenwetriedtopreparewhiskerof 2MgO·B2 O3·H2 Obythephasetransformationof 2MgO·2B2 O3·MgCl2 ·14H2 OinH3BO3solutionunderhydrothermalcondition .Itishope fultopreparewh…     

Ein ungewöhnliches H-Brückenbindungssystem in Rubidium-hydroxiddihydrat,RbOH · 2 H2O

An Unusual System of Hydrogen Bonds in Rubidium Hydroxide Dihydrate, RbOH · 2 H₂O RbOH · 2H₂O was obtained by the reaction of Rb with H₂O and dehydration of the resulting solution by concentrated sulfuric acid. The compound melts at 310 K. The structure was determined by X-ray single crystal methods: The H positions of H₂O were found. The structure consists of a threedimensional H-bonded network of H₂O molecules and OH^?ions. Hydroxide ions are acceptors for four protons of four adjacent water molecules with d(O? O) = 2×2.59 Å and 2×2.82 Å. Oxygen of OH-ions is disordered over a distance of 1.27 Å. Rb has 8 H₂O molecules as nearest neighbours, d(Rb? O) = 3.03 Å to 3.07 Å, OH^?ions are further removed with d(Rb? O) ≥ 3.45 Å.     

Na2Mg(SO3) · 2H2O. Ein neues ternäres Magnesiumsulfit Kristallstruktur,schwingungsspektroskopische und thermoanalytische Untersuchungen

Na₂Mg(SO₃)₂ · 2H₂O. A New Ternary Magnesium Sulfite. Crystal Structure, Thermoanalytical, I.R., and Raman Data Single crystals of the hitherto unknown Na₂Mg(SO₃)₂ · 2 H₂O have been obtained by crystallization from Mg(HSO₃)₂ solutions saturated with NaCl and with the technique of gel crystallization. The crystal structure of the triclinic Na₂Mg(SO₃)₂ · 2 H₂O (P1 , Z = 1, a = 752.4(1), b = 590.3(1), c = 517.8(1) pm, α = 106.25(1), β = 109.80(1), and γ = 101.49(1)°) has been determined using single crystal X-ray diffraction data. The Mg? O distances of the nearly regular MgO₆ octahedra are between 206.6 and 210.5 pm. The MgO₆ octahedra are connected by sulfite bridges forming chains in [001], which are held together by strong hydrogen bridges. The SO₃^2? ions have nearly C_3v symmetry. The results of thermoanalytical and I.R. and Raman spectroscopic measurements are reported and discussed. The O? D stretching modes of HDO molecules in partially deuterated samples show that the water molecules differ strongly from C_2v symmetry.     

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.     

Zinc Hydrogen Ortho Arsenate Trihydrate,ZnHAsO4 · 3 H2O

Zinc hydrogen ortho arsenate trihydrate, ZnHAsO₄ · 3 H₂O has been studied by static isothermal dehydration, X-ray powder diffraction, and infra-red absorption spectral techniques. The results of these studies clearly indicate that the compound is to be formulated as zinc hydroxide dihydrogen ortho arsenate dihydrate, Zn(OH)(H₂ASO₄) · 2 H₂O.