Synthese und Kristallstruktur von Sr2Zn(OH)6 und Ba2Zn(OH)6

Synthesis and Crystal Structure of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ Crystallization from supersaturated sodium hydroxozincate solutions by adding solutions of alkali earth metal hydroxides yields crystals of Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆. The X-ray structure determination on these crystals was successful including all hydrogen positions: Sr₂Zn(OH)₆: P2₁/n, Z = 2, a = 5.794(1) Å, b = 6.160(1) Å, c = 8.141(1) Å, b = 91.23(1)°, N(F ³° 2σ F) = 1127, N(Var.) = 53, R₁/wR₂ = 0.047/0.081Ba₂Zn(OH)₆: P2₁/n, Z = 2, a = 6.043(1) Å, b = 6.336(1) Å, c = 8.451(2) Å, b = 91.23(2)°, N(F ° 2σ F) = 1669, N(Var.) = 54, R₁/wR₂ = 0.029/0.067. Sr₂Zn(OH)₆ and Ba₂Zn(OH)₆ crystallize isotypic in a distorted Li₂O structure type. Sr²⁺ resp. Ba²⁺ form a cubic primitive arrangement. Distorted octahedra of OH^– around Zn²⁺ fill therein alternating cubic gaps in an ordered way.     

Kristallstrukturen und Wasserstoffbrückenbindungen bei β-Be(OH)2 und ϵ-Zn(OH)2

Crystal Structures and Hydrogen Bonding for β-Be(OH)₂ and ϵ-Zn(OH)₂ Crystals of β-Be(OH)₂ sufficient for x-ray structure determination were grown from a saturated hot solution of freshly prepared Be(OH)₂ in NaOH by slowly cooling down and in the case of ϵ-Zn(OH)₂ by electrochemical oxidation of zinc in a NaOH/NH₃ solution. The structures of the isotypic compounds were determined including the H-positions: β-Be(OH)₂: P2₁2₁2₁, Z = 4, a = 4.530(2) Å, b = 4.621(2) Å, c = 7.048(2) Å N(F > 3σ F) = 432, N(parameters) = 36, R/R_w = 0.044/0.052 ϵ-Zn(OH)₂: P2₁2₁2₁, Z = 4, a = 4.905(3) Å, b = 5.143(4) Å, c = 8.473(2) Å N(F > 3σ F) = 1107, N(parameters) = 36, R/R_w = 0.025/0.027For neutron diffraction experiments microcrystalline β-Be(OD)₂ was prepared. With time-of-flight data the D positions were determined giving d(O–D) = 0.954(4) Å. The structures are closely related to that of β-cristobalite: As in SiO₂ a quarter of tetrahedral interstices in a distorted cubic close packed arrangement of O is regularily occupied by the metal atoms. The filled O tetrahedra are twisted against one another in such a way, that O–H…O–H hydrogen bonds are favoured which are surprisingly stronger in the zinc than in the beryllium compound.     

Cis-/Trans-Isomerie bei Bis-(trisalkoxy)-hexavanadaten: cis-Na2[VO7(OH)6{(OCH2)3CCH2OH}2] · 8 H2O,cis-(CN3H6)3[VIVVO13{(OCH2)3CCH2OH}2] · 4,5 H2O und trans-(CN3H6)2[VO13{(OCH2)3CCH2OH}2] · H2O

Cis-/Trans-Isomerism of Bis-(trisalkoxy)-hexavanadates: cis-Na₂[V O₇(OH)₆{(OCH₂)₃CCH₂OH}₂] · 8 H₂O, cis-(CN₃H₆)₃[V^IVV O₁₃{(OCH₂)₃CCH₂OH}₂] · 4.5 H₂O and trans-(CN₃H₆)₂[V O₁₃{(OCH₂)₃CCH₂OH}₂] · H₂O Polyoxovanadates with distorted Lindquist-structure, in which six of the twelve μ₂-oxygen atoms are formally replaced by the oxygen atoms of two coordinated pentaerythritol ligands, can be prepared by a simple method in an aqueous medium. The “fully reduced”, six-fold protonated compound cis-Na₂[VO₇(OH)₆{(OCH₂)₃CCH₂OH}₂] · 8 H₂O ( 1 ), the mixed valence species cis-(CN₃H₆)₃[V^IVVO₁₃{(OCH₂)₃CCH₂OH}₂] · 4.5 H₂O ( 2 ) containing one localized V^IV centre and the “fully oxidized” compound trans-(CN₃H₆)₂[VO₁₃{(OCH₂)₃CCH₂ · OH}₂] · H₂O ( 3 ) have been synthesized and characterized by UV/VIS-, IR- and EPR-spectroscopy, by magnetic measurements, cyclic voltammetry and by a single-crystal X-ray structure analysis. The organic {(CH₂)₃CCH₂OH}³⁺-groups tend to cap the triangular faces formed by μ₂-oxygen atoms of the central approximately octahedral {V₆O₁₉}-unit. Therefore the anions of bis-(trisalkoxy)-hexavanadates can exist in a trans-form as well as in an isomeric cis-form referring to a “basic” plane of four vanadium atoms of the {V₆}-octahedron. The different relative positions of the ligands have a significant influence on the redox potentials of the compounds. For structural details see “Inhaltsübersicht”.     

Ungewöhnliche Koordinationspolyeder um Sauerstoff in Li4Cl(OH)3

Unusual Coordination Polyhedra around Oxygen in Li₄Cl(OH)₃ The pseudobinary system LiOH/LiCl was investigated by X-ray methods. Two compounds, Li₄Cl(OH)₃ and Li₂Cl(OH), were obtained. The crystal structure of Li₄Cl(OH)₃ solved by single-crystal methods is delt with. For Li₂Cl(OH) powder diffraction data are given: Li₄Cl(OH)₃: P2₁/m, Z = 2, a = 5.4096(8) Å, b = 7.382(2) Å, c = 6.2076(8) Å, β = 94.40(1)°, Z(F_o) with (F_o)² ≧ 3σ(F_o)² = 483, Z (parameter) = 50, R/R_w = 0.022/0.025 Li₂Cl(OH): Pmma, Z = 2, a = 7.680(8) Å, b = 4.001(7) Å, c = 3.899(6) Å The hydroxide rich compound crystallizes in a new type of structure which contains puckered layers [Li₄(OH)₃⁺] connected via chloride ions.     

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^?.     

Strukturchemische Verwandtschaft von Kaliumhexahydroxoscandat(III), K3[Sc(OH)6] mit den isotypen Hydroxometallaten Rb3[Sc(OH)6], K3[Cr(OH)6] und Rb3[Cr(OH)6]

Structural Relationship of Potassium Hexahydroxoscandate(III), K₃[Sc(OH)₆] with the Isotypic Hydroxometallates Rb₃[Sc(OH)₆], K₃[Cr(OH)₆], and Rb₃[Cr(OH)₆] Ternary hydroxides M}M^III(OH)₆{ with M^I ? K, Rb and M^III ? Sc, Cr were obtained in the same way as K₃[Cr(OH)₆] [1] from alkali metal amides and d-metal nitrates by a comproportionation reaction of amide and nitrate ions in supercritical ammonia to elementary nitrogen and hydroxide ions at 523 K and 3 ≤ p(NH₃) ≤ 6 kbar within 1 to 3 months. Their structures were determined by single crystal x-ray methods inclusive the positions of the hydrogen atoms. The ratio of size of r(M^I)/r(M^III) is related to the symmetry of these hydroxometallates. Structural relationships between K₃[Sc(OH)₆] and Rb₃[Sc(OH)₆], K₃(Cr(OH)₆], Rb₃[Cr(OH)₆]) and K₄[CdCl₆] [4] are discussed.     

Über Glasbildung und Eigenschaften von Chalkogenidsystemen. XIII. Über die Verbindungen Na6Ge2S6 · 4 CH3OH und Na6Ge2Se6 · 4 CH3OH

Glass Formation and Properties of Chalcogenide Systems. XIII. On the Compounds Na₆Ge₂S₆ · 4 CH₃OH and Na₆Ge₂Se₆ · 4 CH₃OH The glasses Ge₂S₃ and Ge₂Se₃ are soluble in solutions of Na₂S or Na₂Se in CH₃OH forming Na₆Ge₂S₆ · 4 CH₃OH and Na₆Ge₂Se₆ · 4 CH₃OH. On heating the CH₃OH-free substances are formed. From the i.r. and Raman spectra can de seen that the structure of the ions Ge₂S, Ge₂Se, P₂S₆^4?, and of Si₂Cl₆ is of the same type. The formation of the compounds can be regarded as a chemical proof for the existence of [Ge₂S₆] and [Ge₂Se₆] units as structural groups in the glasses Ge₂S₃ and Ge₂Se₃.     

Thallium(I)-thiometallate(II,IV) vom Typ TI2MeMeIVS6

Thallium(I) Thiometallates(II, IV), Tl₂MeMe^IVS₆ The preparation and some properties of the compounds Tl₂MeMe^IVS₆ are reported, where Me^II = Pt, Pd, Ni; Me^IV = Pt, Zr, Sn, Ta. Their structure is discussed in relation to the structure of the alkali compounds A₂MeMe^IVS₆.     

Control of Oxidation States of Transition Elements (Cr,Mn) in Nitridometalates and the Solid Solution Series Li6(Ca1‐xSrx)2[Mn2N6]

The formation of ternary nitridometalates from the elements in the case of the systems Li—Cr, V, Mn—N leads to compounds which contain the transition metals in the highest (V^V, Cr^VI) or a comparably high (Mn^V) oxidation state. In the corresponding calcium and strontium systems, the transition metals show a lower oxidation state (V^III, Cr^III, Mn^III). Transition metals with intermediate oxidation states (Cr^V, Mn^IV) are present in the quaternary (mixed cation) compounds Li₄Sr₂[CrN₆], Li₆Ca₂[MnN₆], and Li₆Sr₂[MnN₆] (R3¯(#148), a = 585.9(3) pm, c = 1908.6(4) pm, Z = 3), as well as in the solid solution series Li₆(Ca_1—xSr_x)₂[MnN₆].     

Li2I(OH): Eine Verbindung mit eindimensional unendlich kantenverknüpften [Li4/2(OH)]+-Pyramiden

Li₂I(OH): A Compound with Onedimensional Infinite Edge Sharing [Li_4/2(OH)⁺] Pyramids The pseudobinary system LiOH/LiI was investigated by X-ray methods. Two compounds, Li₂I(OH) and Li₅I(OH)₄ exist. The structure of Li₂I(OH) was solved by single-crystal data. For Li₅I(OH)₄ lattice constants and space group symmetry are given: Li₂I(OH): Pnma, Z = 4, a = 10.339(4) Å, b = 5.567(1) Å, c = 6.643(2) Å, Z(F_o) mit (F_o)² ≧ 3σ(F_o)² = 439, Z (parameter) = 23, R/R_w = 0.030/0.040 Li₅I(OH)₄: Pmmn or P2₁mn(= Pmn2₁), Z = 2, a = 10.42 Å, b = 5.30 Å, c = 5.81 Å Li₂I(OH) crystallizes in a new type of structure. The motif of a distorted hexagonal close-packed arrangement of iodide ions is penetrated by chains of [Li_4/2(OH)⁺].     

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.     

Hydroxoplatinate(IV) von Calcium,Strontium und Barium

Hydroxoplatinates(IV) of Calcium, Strontium, and Barium CaPt(OH)₆, CaPtO₂(OH)₂, SrPt(OH)₆ · 2 H₂O, and BaPt(OH)₆ were prepared by precipitation from alkali hydroxoplatinate(IV) solution with earth alkali salt solutions, and characterized by X-ray diffraction and chemical analysis. The crystal structure of CaPt(OH)₆, space group P3 1c-;D, with isolated octahedral Pt(OH)₆ ions, was determined by X-ray powder data. Probable hydrogen positions are calculated, and hydrogen bonding is discussed.     

Spectroscopic Studies of Cyclometallated Pd(II) and Pt(II) Complexes: Optical absorption and emission of single crystals of [Pd(thpy)2] and [Pt(thpy)2]

The polarized optical absorption and emission (spectra, decay times) of single crystals of [Pd(thpy)₂] and [Pt(thpy)₂] (thpy ≡ C(3′)-deprotonated form of 2-(2-thienyl)pyridine) at temperatures 1.9 K ? T ? 80 K are reported. The emission of [Pt(thpy)₂] can be influenced strongly by applied magnetic fields (0 ? H ? 6 T). Depending on the central ions Pd and Pt, the lowest excited electronic states of the single complexes are ligand-centered (LC) states and metal-to-ligand charge transfer (MLCT) states, respectively. This difference leads to distinctly dissimilar properties of the emission of both compounds. The experimental data show that the emission of single crystals of [Pd(thpy)₂] and [Pt(thpy)₂] at T ? 30 K originates from several types of traps (defect states of symmetry ³B₂?stabilized below the exciton band) with LC and MLCT character, respectively. In the Pt compound, the ³B₂ is split by spin-orbit coupling into three states. The states B and A, which determine the emission properties, are separated by Δv ～ 13 cm^?1. Both states can mix under the influence of an applied magnetic field yielding an increase of the emission intensity by a factor of ～ 1.5 at H = 6 T.     

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.     

Zur Kristallstruktur von OMF (M = Sb,Ru, Pt,Au)

On the Crystal Structure of O MF (M = Sb, Ru, Pt, Au) OMF (M = Sb, Ru, Pt, Au) were obtained again, but for the first time investigated by X-ray methods. Colourless OSbF and the rubyred compounds ORuF and OPtF crystallize isostructural in space group Ia3 -T_h⁷ (Nr. 206) with a = 1016(1) pm (Sb), a = 1002.6(9) pm (Ru) and a = 1003.6(9) pm (Pt), Z = 8. Yellow OAuF crystallizes trigonal-rhombohedric in space group R3 -D₃₂⁶ (Nr. 148) with a = 775.9(3) pm, c = 711.7(4) pm, Z = 3.     

Zur Struktur der basischen Diquecksilber(I)-nitrate. I kristallstruktur des Hg2OH(NO3) · Hg2(NO3)2

The Crystal Structure of the Basic Dimercury (I) Nitrates. I. The Crystal Structure of Hg₂OH(NO₃) · Hg₂(NO₃)₂ The unit cell of Hg₂OH(NO₃) · Hg₂(NO₃)₂ is orthorhombic, space group Cc2a - standard setting Aba2 (C) — with a = 2017.1(5) pm, b = 935.8(3) pm, c = 1121.7(3) pm and contains 8 formula units. Characteristic are chains [Hg₂OH(Hg₂)_2/2]³⁺ parallel [001]. These are interconnected to a three-dimensional network by nitrate ions coordinated to mercury. The structure achieves additional stabilization through weak hydrogen bonds between oxygen atoms of the hydroxy groups and neighbouring nitrate ions. The bonding relationship of one hydrogen atom to four tetrahedrally correlated oxygen atoms is discussed.     

L'action de l'ammoniac sur l'oxyde cuivrique. et les hydroxo-complexes de cuivre (II)

Using a new mathematical treatment, the nature and stability constants of the simple and mixed complex-species of copper(II) with hydroxyde and ammonia as ligands have been determined. The solubility curves of CuO in heterogeneous equilibrium have been identified in function of pH only and in function of pH and pNH_3tot at 25° and unit ionic strength (NaClO₄). The predominent species in the relatively dilute system limited by the ionic strength are [Cu²⁺], [Cu(OH)₂], [Cu(OH)], [Cu(OH)], [Cu(NH₃)], [Cu(NH₃)], [Cu(NH₃)], [Cu(NH₃) (OH)⁺], [Cu(NH₃)₃(OH)⁺] and [Cu(NH₃)₂(OH)₂].     

Über Oxoosmate(VII) Na5[OsO6] und Li5[OsO6]

On Oxoosmates(VII). Na₅[OsO₆] and Li₅[OsO₆] For the first time bluish black single crystals of Na₅[OsO₆] have been prepared. The structure was determined according to four-circle-diffractometer data. According to powder samples Li₅[OsO₆] is isotypic to Na₅[OsO₆]. Both are of the NaCl-type like Na₅[ReO₆] (space-group C2/m (No. 12, I.T.), Z = 2): Na₅[OsO₆]: a = 568.10(4), b = 975.00(6), c = 559.65(5) pm, β = 111.00° (1), 436 hkl, 4° ? Θ ? 30°, MoK, R = 2.7%, R_W = 2.6%. Li₅[OsO₆]: a = 568.10(4), b =975.00(6), c = 559,65(5) pm, β = 111.00° (1). Effective Coordination Numbers, ECoN, and the Madelung Part of Lattice Energy, MAPLE, are calculated and discussed.     

Mehrkernige Kobaltkomplexe. III. Über meso-[(en)2Co(OH)2Co(en)2] (NO3)4

Polynuclear Cobalt Complexes. III. On meso-[(en)₂Co(OH)₂Co(en)₂] (NO₃)₄ The structure of the title compound has been determined by X-ray analysis and refined to R = 0,060. The crystals are monoclinic, space group very probably C2/m, with cell dimensions a = 16,113(3), b = 10,946(2), c = 7,193(2) Å, β = 113,22(2)° and Z = 2. The configuration of the cation is ΔΛ IR. and UV./VIS. spectroscopic data are given.     

Redshifts and blueshifts of OH vibrations

Ab initio calculations of potential energy, dipole moment, equilibrium OH distance, force constants, and anharmonic frequencies, and correlation between these quantities, are presented for a water molecule and an OH^? ion in a uniform electric field of varying field strength. It is explained why a bound H₂O molecule in nature always experiences a frequency downshift with respect to the free molecule, and a bound OH^?1 ion, either a downshift or an upshift. The frequency-field variation is well accounted for by the expression Δν_OH α ?E‖ · (d μ/dr_OH + 1/2 · ?μ/?r_OH). A frequency maximum occurs at the field strength where ?μ‖^tot/?r_OH ～ 0. Two cases can be discerned: (1) the frequency maximum falls at a positive field strength when dμ/dr_OH is positive (this is the situation for OH^?), and (2) the maximum frequency falls at a negative field when dμ/dr_OH is negative (this occurs for water). In general, for an OH bond in a bonding situation where the intermolecular interactions are dominated by electrostatic forces, the nonlinearity of the frequency shift with respect to an applied field is governed by how close to the frequency maximum one is, i.e., by both dμ/dr_OH and ?μ/?r_OH. Correlation curves between the external linear force constant, k^ext, and r_OH,e are closely linear over the whole field range studied here, whereas the frequency vs. r_OH,e and force constants vs. r_OH,e correlation curves form two approximately linear, parallel branches, corresponding to “before” and “after” the maximum in the frequency vs. field curves. Each branch of the ν vs. r_OH,e curves has a slope of ～ ? 16,000 cm^?1/Å. © 1993 John Wiley & Sons, Inc.