Die erste Kristallstrukturanalyse einer Iodylverbindung

The First Crystal Structure Analysis of an Iodyl Compound Single crystals of (IO₂)₂S₂O₇ were obtained for the first time by reacting iodic acid and oleum at 195°C. According to the results of a X-ray structure determination (monoclinic, P2₁/a, a = 885.0(2), b = 1037.3(2), c = 915.8(2) pm, β = 94.75(2)°, Z = 4, 1466 diffractometer data, R₁ = 0.033, wR² = 0.063), (IO₂)₂S₂O₇ contains dimeric iodyl cations (IO₂), which are connected by disulfate groups thus forming polymeric strands. Strikingly, the I? O-distances range almost continously from 174 pm (strong intramolecular bonds) to ? 300 pm (van der Waals contacts).     

Osmotic coefficients and activity coefficients of lodic acid at high concentrations

Isopiestic vapor pressure measurements have been used to determine the osmotic coefficients of aqueous solutions of iodic acid at molalities from 0.1 to 17 mole-kg^?1 at 25°C. The isopiestic standards were solutions of sodium chloride and solutions of sulfuric acid. Because of the corrosive nature of iodic acid, platinum cups were used. Stoichiometric activity cofficients of iodic acid were derived by a Gibbs-Duhem integration. The activity coefficients for solutions of molality greater than 0.5 mole-kg^?1 cannot be accounted for in terms of the two equilibria, namely, the acidic dissociation of iodic acid and formation of the ion H(IO₃) ₂ ^? , shown by Pethybridge and Prue to explain adequately the behavior in dilute solutions. The activity coefficient is unexpectedly small in concentrated solutions, suggesting the formation of neutral aggregates of iodic acid. The presence of dimers and tetramers, or alternatively trimers and tetramers, can explain the observed results up to a molality of 7 mole-kg^?1.     

Synthese und Kristallstruktur von Y(HSO4)3-I und Y(HSO4)3 · H2O

Syntheses and Crystal Structures of Y(HSO₄)₃-I and Y(HSO₄)₃ · H₂O Lath shaped crystals of Y(HSO₄)-I are obtained by treatment of Y₂O₃ with conc. sulfuric acid at 200 °C. Y(HSO₄)₃-I crystallizes orthorhombic (Pbca, Z = 8, a = 1201.5(1), b = 953.76(8), c = 1650.4(1) pm, R_all = 0.0388). In the crystal structure Y³⁺ is coordinated by eight monodentate HSO₄^– groups. Colorless, plate like single crystals of Y(HSO₄)₃ · H₂O grew from a solution of Y₂O₃ in 85% sulfuric acid upon cooling. In the crystal structure of the triclinic compound (P1, Z = 2, a = 679.8(1), b = 802.8(2), c = 965.9(2) pm, α = 79.99(2)°, β = 77.32(2)°, γ = 77.50(2)°, R_all = 0.0264) Y³⁺ is surrounded by seven HSO₄^– groups and one molecule of water.     

Kristallstrukturuntersuchungen an Verbindungen des Typs A3(M,Nb)8O21 (A  Tl,Ba; M  Fe,Ni)

Crystal Structure Investigations of Compounds with the A₃(M, Nb)₈O₂₁-Type (A ? Tl, Ba; M ? Fe, Ni) Tl₃Fe_0,5Nb_7,5O₂₁ (A), a hitherto unknown phase of the A₃(M, Nb)₈O₂₁-type, and Ba₃Fe₂Nb₆O₂₁ (B), Ba₃Ni_1.33Nb_6,66O₂₁ (C) were prepared and investigated by single crystal X-ray technique. ((A): a = 9.145(1), c = 11.942(1) Å; (B): a = 9.118(2), c = 11.870(1) Å; (C) a = 9.173(3), c = 11.923(1) Å, space group D? P6₃/mcm, Z = 2). There is a statistic occupation of the M-positions by Nb⁵⁺ and Fe³⁺ or Nb⁵⁺ and Ni²⁺, respectively. An other compound Ba₃Fe₂Ta₆O₂₁ is partially ordered in respect to Ta⁵⁺ and Fe³⁺. Calculations of the Coulomb-part of lattice energy are discussed.     

Einfach und doppelt deprotonierte Maleinsäure in Praseodym‐hydrogenmaleat‐octahydrat,Pr(C4O4H3)3 · 8 H2O,und Praseodym‐maleatchlorid‐tetrahydrat,Pr(C4O4H2)Cl · 4 H2O

Single and Double Deprotonated Maleic Acid in Praseodymium Hydrogenmaleate Octahydrate, Pr(C₄O₄H₃)₃ · 8 H₂O, and Praseodymiummaleatechloride Tetrahydrate, Pr(C₄O₄H₂)Cl · 4 H₂O Single crystals of Pr(C₄O₄H₃)₃ · 8 H₂O grew by slow evaporation of a solution which had been obtained by dissolving Pr(OH)₃ in aqueous maleic acid. The triclinic compound (P1, Z = 2, a = 728.63(3), b = 1040.23(3), c = 1676.05(8) pm, α = 72.108(2)°, β = 87.774(2)°, γ = 70.851(2)°, R_all = 0.0261) contains Pr³⁺ ions in ninefold coordination of oxygen atoms which belong to two monodentate maleate ions and seven H₂O molecules. There is one further non‐coordinating maleate ion and one crystal water molecule in the unit cell. Thermal treatment of Pr(C₄O₄H₃)₃ · 8 H₂O leads first to the anhydrous compound which then decomposes to the respective oxide in two steps upon further heating. Evaporation of a solution of Pr(C₄O₄H₃)₃ · 8 H₂O which contained additional Cl^– ions yielded single crystals of Pr(C₄O₄H₂)Cl · 4 H₂O. In the crystal structure (monoclinic, P2₁/c, Z = 4, a = 866.0(1), b = 1344.3(1), c = 896.9(1) pm, β = 94.48(2)°, R_all = 0.0227), the Pr³⁺ ions are surrounded by nine oxygen atoms. The latter belong to four H₂O molecules and three maleate ions. Two of the latter act as bidentate ligands.     

Über Oxidtelluride (M2O2Te) der leichten Lanthanide (M = La–Nd,Sm–Ho) im A-Typ mit anti-ThCr2Si2-Struktur

On Oxytellurides (M₂O₂Te) of the Early Lanthanides (M = La–Nd, Sm–Ho) with A- or anti -ThCr₂Si₂-Type Crystal Structure By reacting elementary lanthanide metal (M = La–Nd, Sm–Ho) with tellurium dioxide (TeO₂) in a 2 : 1 molar ratio, it is possible to obtain pure and single-phase oxytellurides of the composition M₂O₂Te at 750 °C in evacuated silica tubes within a few days. When larger quantities of cesium chloride (CsCl) are added as flux, plate-like single crystals with square cross-section are formed which are not sensitive to hydrolysis and very suitable for crystal structure refinements from X-ray data. In the anti-ThCr₂Si₂ analogous crystal structure (tetragonal, I4/mmm, Z = 2; La₂O₂Te: a = 412.31(4), c = 1309.6(1) pm; Ce₂O₂Te: a = 408.17(4), c = 1294.7(1) pm; Pr₂O₂Te: a = 405.62(4), c = 1285.8(1) pm; Nd₂O₂Te: a = 403.08(4), c = 1277.1(1) pm; Sm₂O₂Te: a = 399.83(4), c = 1265.5(1) pm; Eu₂O₂Te: a = 397.56(4), c = 1257.9(1) pm; Gd₂O₂Te: a = 396.20(4), c = 1253.2(1) pm; Tb₂O₂Te: a = 393.89(4), c = 1245.4(1) pm; Dy₂O₂Te: a = 392.34(4), c = 1240.3(1) pm; Ho₂O₂Te: a = 390.57(6), c = 1239.0(3) pm) the M³⁺ cations are surrounded by nine anions (4 O^2– und 4 + 1 Te^2–) in the shape of a capped square antiprism. The anions show coordination numbers of four (O^2–: tetrahedra) and eight plus two (Te^2–: bicapped cubes) with respect to the cations. PbO-analogous square {[OM_4/4]₂}²⁺ triple layer slabs are present parallel (001), which originate through two-dimensional infinite linking of [OM₄]¹⁰⁺ tetrahedra via two trans-orientated pairs of edges (i. e. four edges altogether). These cationic layers are piled alternatingly along [001] with likewise quadratic single layers of Te^2– anions, which take care of the three-dimensional coherence as well as of the charge balance.     

[TMPA]4[Si8O20] · 34 H2O and [DDBO]4[Si8O20] · 32 H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations

[TMPA]₄[Si₈O₂₀] · 34 H₂O ( 1 ) and [DDBO]₄[Si₈O₂₀] · 32 H₂O ( 2 ) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO₂. The crystal structures have been determined by single-crystal X-ray diffraction. 1 : Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2 : Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P2₁/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si₈O₂₀]^8? anions and H₂O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H₂O molecules and six cations (TMPA, [C₈H₂₀N₂]²⁺, or DDBO, [C₈H₁₈N₂]²⁺). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing ²⁹Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]₆[Si₈O₁₈(OH)₂] · 48.5 H₂O ( 3 ) with 1,1-dimethylpiperidinium (DMPI, [C₇H₁₆N]⁺) guest cations.     

Synthese,Eigenschaften und Kristallstruktur von Cu3Mo8O23X2 (X = Cl,Br, I)

Synthesis, Properties, and Crystal Structure of Cu₃Mo₈O₂₃X₂ (X = Cl, Br, I) Single crystals of the Cu₃Mo₈O₂₃X₂ compounds were grown by chemical transport reactions at the lower temperature of a gradient 873–823 K without extra transport agent (auto transport). As DTA/TG measurements indicate, the gaseous compounds, necessary for chemical transport reactions, are formed by partial decomposition of Cu₃Mo₈O₂₃X₂ at 873 K. Cu₃Mo₈O₂₃Br₂ crystallizes with the orthorombic space group Pbcm (a = 4.021(1), b = 22.978(2), c = 21.673(2) Å, Z = 4). The crystal structure consists of pentagonal columns ¹_∞[Mo₆O₇O_20/2] linked by additional MoO_6/2 octahedra. All the polyhedra(pentagonal bipyramide, octahedra) are distorted. Infinite chains ¹_∞[Cu₃Br₂] along [100] are arranged in tunnels with s‐like square shape, left open by the pentagonal columns. Cu₃Mo₈O₂₃Cl₂ (a = 4.010(1), b = 22.942(2), c = 21.639(2) Å) and Cu₃Mo₈O₂₃I₂ (a = 4.052(1), b = 23.075(2), c = 21.719(2) Å) are isotypic.     

Untersuchungen zu Struktur und physikalischen Eigenschaften von Oxiden der LaPd2O4-Familie

Investigations on Structure and Physical Properties of some New Members of the LaPd₂O₄ Family The new mixed valent oxopalladates MPd₂O₄ (M = Pr, Nd, Gd, Y) have been synthesized from the binary oxides in presence of a solid oxygen carrier (KClO₃) by applying hydrostatic pressure (ca. 2 GPa). According to X-ray investigations these oxides crystallize in space group I 4₁/a (No. 88) and are isotypic to LaPd₂O₄ (PrPd₂O₄: a = 5.8382(2), c = 10.1687(5) Å; NdPd₂O₄: a = 5.8419(3), c = 10.1949(6) Å; GdPd₂O₄: a = 5.7799(3), c = 10.0677(8) Å; YPd₂O₄: a = 5.7359(3), c = 9.9829(8) Å). The crystal structure consists of square planar PdO₄ units which are stacked to form columnar arrangements along [1 00] and [0 10], respectively. The PdO₄ squares are connected via common corners to a three-dimensional framework. By substitution of Pr³⁺, Nd³⁺, Gd³⁺ and Y³⁺ for lanthanum the Pd? Pd distances decrease and the electrical conductivities increase. The oxopalladates investigated in this work are black, paramagnetic and semiconducting. At ambient pressure they decompose at temperatures above 880 K into elemental palladium and the binary rare earth oxides.     

Bildung oktaedrischer Komplexe durch cis-Addition an planar-quadratisches Bis(oxamidoximato)nickel(II): drei Strukturbeispiele

Formation of Octahedral Complexes via cis-Addition to Square Planar Bis (oxamideoximato)nickel(II): Three Structure Examples In the reaction of orange square planar bis(oxamide oximato)nickel(II) with acids, blue to blue-green octahedral complexes are formed with neutral oxamide oximide ligands and two acid anions in cis-positions. Three compounds are described: cis-dichlorobis(oxamide oxime)nickel(II) ( 1 ), NiCl₂(C₂H₆N₄O₂)₂, M_r = 365.81, monoclinic P2₁/n, a = 6.641(2), b = 14.086(4), c = 13.473(3) Å, β = 96.26(2)°, V = 1 252.8 ų, Z = 4, d_c = 1.94 gcm^?3, final R_w = 0.031 for 4090 reflections. In cis-di(sulfanilato)bis(oxamide oxime)nickel(II) dihydrate ( 2 ) one sulfanilic anion coordinates via the sulfonic acid group, the other one via the amino group; Ni(C₆H₆NO₃S)₂(C₂H₆N₄O₂)₂ · 2 H₂O, M_r = 675.30, monoclinic P2₁, a = 6.879(3), b = 14.305(5), c = 13.930(5) Å, β = 103.62(4)°, V = 1332 Å, Z = 2, d_c = 1.68 gcm^?3, R = 0.067 for 2693 reflections. In catena-μ-(phthalato)bis(oxamide oxime)nickel(II) tetrahydrate ( 3 ) bidentate bridging phthalate anions lead to chain formation; Ni(C₈H₄O₄)(C₂H₆N₄O₂)₂ · 4H₂O, M_r = 531.09, monoclinic P2₁/c, a = 10.633(8), b = 11.324(5), c = 17.680(14) Å, β = 98.25(7)°, V = 2107 ų, Z = 4, d_c = 1.67 gcm^?3. Final R = 0.110 for 3290 reflections.     

Ho2Te4O11 und Ho2Te5O13: Zwei tellurdioxidreiche Oxotellurate(IV) des dreiwertigen Holmiums

Ho₂Te₄O₁₁ and Ho₂Te₅O₁₃: Two Telluriumdioxide‐rich Oxotellurates(IV) of Trivalent Holmium Ho₂Te₄O₁₁ (monoclinic, C2/c; a = 1240.73(8), b = 511.21(3), c = 1605.84(9) pm, β = 106.142(7)°; Z = 4) and Ho₂Te₅O₁₃ (triclinic, P1; a = 695.67(5), b = 862.64(6), c = 1057.52(7) pm, α = 89.057(6), β = 86.825(6), γ = 75.056(6)°; Z = 2) are obtained by the reaction of holmium sesquioxide with tellurium dioxide in appropriate molar ratios (Ho₂O₃ : TeO₂ = 1 : 4 and 1 : 5, respectively) in evacuated silica tubes within eight days at 800 °C. The application of cesium chloride (CsCl) as flux in about five times molar excess secures fast and complete reactions to the single‐crystalline products aimed at. In the crystal structure of Ho₂Te₄O₁₁ [HoO₈] polyhedra are connected via oxygen edges thereby building up a network {[Ho₂O₁₀]^14–} (001). On the other hand, the crystal structure of Ho₂Te₅O₁₃ exhibits oxygen‐linked [(Ho1)O₈] and [(Ho2)O₇] polyhedra, which form ribbons {[(Ho1)₂(Ho2)₂O₂₀]^28–} running along [100]. Common to both structures, however, is the stereochemical activity of the non‐bonding electron pairs (“lone pairs”) of all the of the Te⁴⁺ cations (Te1 and Te2 in Ho₂Te₄O₁₁, Te1–Te5 in Ho₂Te₅O₁₃) causing ψ¹‐polyhedral figures of coordination with 3 + 1, 4 and 3 + 2 oxygen atoms, respectively, around the central atoms.     

1D Polyoxometalate‐based Inorganic‐Organic Hybrid Derived from ß‐Octamolybdate — Synthesis and Crystal Structure of [CoII(2, 2′‐bipy)2]2[Mo8O26]

A polyoxometalate‐based inorganic–organic hybrid compound [Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆] ( 1 ) was synthesized by hydrothermal methods and structurally characterized by IR spectrum, TG analysis and X‐ray diffraction. The compound crystallizes in the monoclinic system, space group P2₁/n, a = 10.0681(2), b = 16.4467(2), c = 15.7838(3) Å, β = 100.046(1)°, V = 2573.52(8) ų, Z = 2. The structure of 1 is built up from β‐[Mo₈O₂₆]^4? subunits covalently linked via [Co^II(2, 2′‐bpy)₂]²⁺ fragments into a infinite 1D {[Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆]}_∞ polymer.     

Influence of Coordination Geometry on the Ring Opening of Benzoxazine: Oxidovanadium(V), Dioxidomolybdenum(VI) and Dioxidotungsten(VI) Complexes of Benzoxazine Based Ligands and their Bio Inspired Catalytic Applications

Mono benzoxazine appended N-capped amino bis(disubstitutedphenol) ligands [ II ( a–c )] upon reaction with V^VO(OEt)₃ in a 1 : 1 molar ratio in EtOH/MeOH give [{V^VO}en(3,5-dtbb)₃] ( 1 ), [{V^VO}en(3-tb,5-mb)₃] ( 2 ) and [{V^VO}en(3,5-dmb)₃] ( 3 ). During the reaction, the benzoxazine ring opens with the loss of methylene group and the newly formed ligands, N,N-bis(2-hydroxy-3,5-disubstitutedbenzyl)-N’-2-hydroxy-3,5-disubstituted benzyledene-1,2-diaminoethane [ III ( a–c )], behave as tribasic pentadentate in these complexes. Under similar conditions, when [M^VIO₂(acac)₂] (M=Mo or W; Hacac=acetylacetone) reacts with II ( a–c ), these ligands retain their identity and form cis-[M^VIO₂] complexes, [{Mo^VIO₂}{en(3,5-dtbb)₂(6,8-dtbbenzox)}] ( 4 ), [{Mo^VIO₂}{en(3-tb,5-mb)₂(6-tb,8-mbbenzox)}] ( 5 ) and [{Mo^VIO₂}{en(3,5-dmb)₂(6,8-dmbenzox)}] ( 6 ), [{W^VIO₂}{en(3,5-dtbb)₂(6,8-dtbbenzox)}] ( 7 ), and [{W^VIO₂}{en(3-tb,5-mb)₂(6-tb,8-mbbenzox)}] ( 8 ). However, the benzoxazine ring ruptures in case of ligand IIc under these conditions and form [{W^VIO₂}{en(3,5-dmb)₃}] ( 10 ), similar to complexes 1–3 . Complex [{W^VIO₂}{en(3,5-dmb)₂(6,8-dmbenzox)}] ( 9 ), having structure similar to 4–8 , could only be obtained when the reaction was carried out in toluene. Not only 9 , even complexes 4–8 can be isolated in toluene. Rupturing of both benzoxazine rings has also been experienced when ligands 1,2-bis(6,8-disubstitutedbenzo[e][1,3]oxazin-3(4H)-yl)ethane [ I ( a–c )] react with [M^VIO₂(acac)₂] (M=Mo or W) in MeOH and give salan type complexes [(M^VIO₂)en(3,5-dtbb)₂] [M=Mo ( 11 ), M=W ( 14 )], [(M^VIO₂)en(3-tb,5-mb)₄] [M=Mo ( 12 ), M=W ( 15 )] and [(M^VIO₂)en(3,5-dmb)₄] [M=Mo ( 13 ), M=W ( 16 )]. Complexes 1–9 have been used as catalyst for the multicomponent Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and oxidative bromination of phenol derivatives.     

Rubidium‐ und Caesium‐Verbindungen mit dem Isopolyanion [Ta6O19]8– – Synthesen,Kristallstrukturen, thermische und schwingungsspektroskopische Untersuchungen der Oxotantalate A8[Ta6O19] · n H2O (A = Rb,Cs; n = 0, 4, 14)

Rubidium und Caesium Compounds with the Isopolyanion [Ta₆O₁₉]^8– – Synthesis, Crystal Structures, Thermogravimetric and Vibrational Spectrocopic Analysis of the Oxotantalates A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) The compounds A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) contain the isopoly anion [Ta₆O₁₉]^8–, which consists of six [TaO₆] octahedra connected via corners to form a large octahedron. They transform into each other by reversible hydratation/dehydratation processes, as shown from thermoanalytic measurements (TG/DSC), and show also structural similarities. Cs₈[Ta₆O₁₉] (tetragonal, I4/m, a = 985.9(1) pm, c = 1403.3(1) pm, Z = 2), the isotypic phases A₈[Ta₆O₁₉] · 14 H₂O (A = Rb/Cs; monoclinic, P2₁/n, a = 1031.30(6)/1055.4(1) pm, b = 1590.72(9)/1614.9(6) pm, c = 1150.43(6)/1171.4(1) pm, β = 100.060(1)/99.97(2)°, Z = 2) and Rb₈[Ta₆O₁₉] · 4 H₂O (monoclinic, C2/c, a = 1216.9(4) pm, b = 1459.2(5) pm, c = 1414.7(4) pm, β = 90.734(6)°, Z = 4) have been characterised on the basis of single crystal x‐ray data. Furthermore the RAMAN spectra allow a detailled comparison of the hexatantalate ions in the four compounds.     

Hydrogenselenate der Selten‐Erd‐Elemente: Synthese und Kristallstruktur von La(HSeO4)3 und Gd(HSeO4)(SeO4)

Hydrogenselenates of Rare Earth Elements: Syntheses and Crystal Structures of La(HSeO₄)₃ and Gd(HSeO₄)(SeO₄) Colorless transparent single crystals of La(HSeO₄)₃ (hexagonal, P6₃/m, Z = 2, a = 971.7(1), c = 616.98(8) pm, R_all = 0.0440) were obtained from the reaction of La₂O₃ and conc. selenic acid. La(HSeO₄)₃ is isotypic with the corresponding hydrogensulfate. Its structure can be seen as a variant of the UCl₃ type structure with complex anions and contains the La³⁺ ions in ninefold coordination of oxygen atoms. Single crystals of Gd(HSeO₄)(SeO₄) crystallize from a solution of Gd₂O₃ in selenic acid (70% H₂SeO₄). In the orthorhombic crystal structure (Pbca, Z = 8, a = 920.4(1), b = 1351.6(2), c = 1004.0(1) pm, R_all = 0.0276) the Gd³⁺ ions are coordinated by eight oxygen atoms belonging to four SeO₄^2– and four HSeO₄^– ions. These are surrounded by four Gd³⁺ ions.     

Synthesis and Crystal Structures of Cs5Nb2S4X9 – Double Salts Containing New Cluster Anions [Nb2(μ-S2)2X8]4– (X = Cl,Br)

Bis(disulfide)bridged Nb(+4) cluster halide complexes [Nb₂S₄X₈]^4– (X = Cl, Br) were prepared by acid hydrolysis of [Nb₂S₄(NCS)₈]^4– in concentrated aqueous HCl or HBr, solution from which they can be isolated as double salts Cs₅[Nb₂S₄X₈]X (X = Cl, 1 ; X = Br, 2 ). The crystal structures of 1 and 2 were determined. The isolation and X-ray structure of oxonium salt (H₃O)₅ [Nb₂S₄Cl₈]Cl ( 3 ) is also reported. 1 – 3 contain new [Nb₂S₄X₈]^4– anions which can also be viewed as excised building blocks of polymeric solids NbS₂X₂. The extra halogen resides in the center of octahedron formed by six Cs⁺ or H₃O⁺ ions. All the three salts are isostructural and crystallize in tetragonal space group Immm with the following parameters: a = 10.269(2), b = 16.343(2), c = 7.220(1) Å for 1 , a = 10.934(1), b = 16.613(2), c = 7.470(1) Å for 2 , a = 9.639(1), b = 16.031(1), c = 7.071(1) Å for 3 . The parameters of the Nb₂S₄ core are only slightly affected by the change from Cl to Br.     

Crystal Structures and Spectral Studies of [Ph3Sn(O2AsMe2)], [Bu2ClSn(O2AsMe2)] and [PhClSn(O2AsMe2)(μ‐OMe)]2

[Ph₃Sn(O₂AsMe₂)] ( 1 ) and [PhClSn(O₂AsMe₂)(μ‐OMe)]₂ ( 3 ) have been synthesized by treatment of Ph₃SnCl and Ph₂SnCl₂ with Na(O₂AsMe₂) in methanol, respectively. [Bu₂ClSn(O₂AsMe₂)] ( 2 ) has been prepared by the reaction of Bu₂SnCl₂ with HO₂AsMe₂ in methanol. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/n with a = 699.8(1), b = 1961.4(2), c = 1433.6(2) pm, β = 95.17(1)°, and Z = 4. 2 also crystallizes monoclinic in the space group P2₁/m, the cell parameters being a = 480.6(1), b = 1992.7(2), c = 808.8(1) pm, β = 103.726(5)°, and Z = 2. Both compounds form infinite chains with alternating (Me₂AsO₂)^? and (R₃Sn)⁺ or (R₂ClSn)⁺ units. The dimer 3 consists of 8‐membered (OSnOAs)₂ rings in which the tin atoms are bridged by methanolate bridges. It crystallizes triclinic in the space group with a = 822.8(2), b = 910.4(2), c = 929.2(2) pm, α = 77.04(3)°, β = 82.35(3)°, γ = 68.69(3)°, and Z = 1 for the dimer. The vibrational and mass spectra of 1 , 2 and 3 are given and discussed.     

Syntheses and Structures of Two New Cu/Nb/pyrazine Complexes: Three dimensional CuNb(pyz)2OF5 · (pyz)(H2O) and two dimensional [Cu(pyz)2.5]+ [NbF6]− · (pyz)

Crystals of CuNb(pyz)₂OF₅ · (pyz)(H₂O) ( 1 ) and [Cu(pyz)_2.5]⁺ [NbF₆]^? · (pyz) ( 2 ) were grown (150°C and autogeneous pressures) from CuO, 1/2(Nb₂O₅), (HF)_x · pyridine, and H₂O in excess pyrazine. Light blue single crystals of ( 1 ) are orthorhombic, crystallizing in space group Cccm (No. 66), with a = 14.547(1) Å, b = 16.135(2) Å, c = 13.803(2) Å, and Z = 8. The structure of ( 1 ) contains corner shared [Cu(pyz)_4/2F_2/2]⁺, [Cu(pyz)_4/2O_2/2], and [NbF₄O_1/2F_1/2]^?0.5 octahedra. Orange crystals of ( 2 ) are monoclinic, crystallizing in space group C2/c (No. 15), with a = 11.792(8) Å, b = 17.123(3) Å, c = 17.051(5) Å, β = 90.04(4)°, and Z = 8. The structure of ( 2 ) contains puckered rings of corner shared [Cu(pyz)(pyz)_3/2]⁺ tetrahedra and isolated [NbF₆]^? anions within the rings.     

Pr(BO2)3 und PrCl(BO2)2: Zwei meta‐Borate des Praseodyms im Vergleich

Pr(BO₂)₃ and PrCl(BO₂)₂: Two Praseodymium meta‐Borates in Comparison Single‐crystalline PrCl(BO₂)₂ can be obtained by the reaction of praseodymium, Pr₆O₁₁ and PrCl₃ with a small excess of B₂O₃ in evacuated silica tubes after seven days at 850 °C. If NaCl is additionally used as flux, single crystals of Pr(BO₂)₃ dominate the main product. Both praseodymium(III) meta‐borates are air and water stable. The crystals of PrCl(BO₂)₂ emerge as long, thin, pale green needles which tend to severe twinning due to their fibrous habit. The crystal structure (triclinic, P1¯; a = 420.56(4), b = 655.42(7), c = 808.34(8) pm, α = 82.361(8), β = 89.173(9), γ = 71.980(7)°, Z = 2) exhibits zigzag chains {[(B1)o^t_1/1O^e_2/2(B2)O^t_1/1O^e_2/2]²⁻} (≡ {[BO₂]⁻}) of corner‐linked [BO₃]³⁻ triangles with syndiotactic orientation of the terminal oxygen atoms which are running parallel to the [100] direction. The Pr³⁺ cations are surrounded by three Cl⁻ and seven O²⁻ anions with the shape of a tetracapped trigonal prism. The green, transparent crystals of Pr(BO₂)₃ (monoclinic, C2/c; a= 984.98(9), b = 809.57(8), c = 641.02(6) pm, β = 126.783(9)°, Z = 4) appear either lath‐shaped or rather spherical. In the crystal structure the B³⁺ cations reside both in trigonal planar as well as in tetrahedral coordination of oxygen atoms. Both types of borate polyhedra ([BO₃]³⁻ and [BO₄]⁵⁻) are linked via corners to form chains of the composition {[(B2)‐O^t_1/1O^e_2/2(B1)O^e_4/2(B2)O^t_1/1O^e_2/2]³⁻} (≡ {[BO₂]⁻}) which run parallel [101]. The coordination sphere of the Pr³⁺ cations consists of ten oxide anions which build up a bicapped square antiprism.     

Ein neues Lithosilicat: Rb5LiNiSi2O8 = Rb5[LiNiSi2O8]

A New Lithosilicate: Rb₅LiNiSi₂O₈ = Rb₅[LiNiSi₂O₈] Nearly colourless crystals of Rb₅LiNiSi₂O₈ resulted by heating intimate mixtures of RbO_0.6, LiO_0.5, and SiO₂ (Rb : Li : Si = 3 : 1.2 : 1) in tightly closed Ni-tubes. The crystal structure was determined (four-circle-diffractometer-data, 1 733 of 1 740 I₀ (h kl), R = 6.9%, R_w = 5.5%, parameters see text). The new “Lithosilicate” crystallizes monoclinic (Space group C2/c) with a = 860.0(2), b = 1 026.2(2), c = 1 376.1(3) pm, β = 101.28(2)° (Guinier-Simon-powder-data), Z = 4. The structure is built up by chains [O_2/2SiO₂LiO₂SiO₂NiO_2/22] where Si⁴⁺ resp. Li⁺ are coordinated tetrahedrally, Ni²⁺ however quadratic planar. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, MEFIR, are given.