CLUSTER CONVERSION OF [MoW2O2(O2CEt)9]− TO [MoW2O4(O2 CEt)8]4- BY CHROMIUM HEXACARBONYL CRYSTAL STRUCTURES OF Na[MoW2O2(O2CMe)9] · H2O, [MoW2O2(O2CEt)6(H2O)3] ZnCl4 · 2H2O AND Na2Cr2[MoW2O4(O2CEt)8]2

Abstract

Reactions of Mo(CO)₆ with Na₂WO₄ · 2H₂O in refluxing carboxylic anhydride produce the triangular bioxo-capped mixed-metal carboxylate clusters Na[MoW₂O₂(O₂CR)₉] (R = Me, 1; Et, 2), the propionate being hydrolyzed in 2M HCl containing ZnCl₂ to form [MoW₂O₂(O₂CEt)⁶(H₂O)₃]ZnCl₄·2H₂O (3). Cluster 2 is converted to the incomplete cuboidal tetraanion [MoW₂O₄(O₂CEt)₈]^4- upon reacting with Cr(CO)₆ in propionic anhydride at 120°, the latter species being trapped by Cr^3± and Na^± ions in the reaction mixture to afford the octanuclear heterometallic chain-like cluster Na₂Cr₂ [MoW₂O₄(O₂CEt)₈]₂ (4). Clusters 1, 3 and 4 have been characterized by X-ray crystallography with the following crystal data, for 1: monoclinic, space group P2₁/c, a = 16.666(8), b = 11.096(3), c = 16.541(7) Å, β = 94.60(4)°, V = 3048.9 ų, Z = 4, R, Rw = 0.070, 0.079; for 3, monoclinic, space group Cm, a = 10.259(3), b = 15.756(3), c = 10.870(3) Å, β = 96.18(3)°, V = 1746.8 ų, Z = 2, R, Rw = 0.028, 0.034; for 4, triclinic, space group P-1, a = 13.013(5), b = 14.005(4), c = 12.357(4) Å, α = 109.71(2), β = 117.77(3), γ = 90.41(3)°, V = 1838.9 ų, Z = 1, R, Rw = 0.037, 0.042.     

The Mixed Valence Tungsten(IV,V) Compound Na[W2O2Br6]

The reaction of W₆Br₁₂, NaBr, and WO₂Br₂ in the presence of Br₂ in a sealed silica tube yields Na[W₂O₂Br₆] together with WOBr₄ and WO₂Br₂ in the low temperature zone (temperature gradient 1030/870 K). Na[W₂O₂Br₆] crystallizes orthorhombically in the space group Immm (no. 71) with a = 3.775 Å, b = 10.400 Å, c = 13.005 Å and Z = 2. Pairs of condensed trans-[WO₂Br₄] octahedra with a common Br₂ edge form along [100] double chains [W₂O_4/2Br₆]^1– via the oxygen atoms. The mixed valent tungsten atoms are bonded to W₂ pairs with a 2 c–3 e bond (d(W–W) = 2.946 Å, d(W–O) = 1.888 Å, d(W–Br^b) = 2.537 Å, d(W–Br^t) = 2.535 Å, ∢O–W–O = 177.4°, ∢Br^b–W–Br^b (endocyclic) = 109.0°). The Na⁺ cations connect the anionic double chains to form two-dimensional layers parallel (001), which interact by van der Waals forces. The cations are eightfold coordinated by a cube of the terminal Br^t ligands of the polymeric anions (d(Na–Br) = 3.138 Å). Na[W₂O₂Br₆] may be discussed as an intercalation compound of the oxide bromide WOBr₃.     

Synthesis,characterization and X-ray structure of one-dimensional polymeric complexes with triangular molybdenum clusters as building blocks: Na2Ga2[Mo3O4(O2CEt)8]2 and Na2AlGa[Mo3O4(O2CEt)8]2

The heterometallic polymeric cluster complexes Na₂Ga₂[Mo₃O₄(O₂CEt)₈]₂ (1) and Na₂AlGa[Mo₃O₄(O₂CEt)₈]₂ (2) have been prepared by reaction of Mo(CO)₆, NaMoO₄·2H₂O with GaCl₃ and a mixture of AlCl₃ and GaCl₃ (1:1 molar ratio), respectively, in heated propionic anhydride and characterized by X-ray crystallography. The structures are isostructural and each consists of two triangular propionate cluster units [Mo₃O₄(O₂CEt)₈]⁴⁻, which act as polydentate ligands to link trivalent heterometal and sodium ions forming one-dimensional chain structures. Both clusters decompose in 2 M HCl at room temperature to produce discrete [Mo₃O₄]⁴⁺ cluster units. Thermal analysis of 1 reveals that the complex is air stable up to 250°C. IR spectra show the characteristic bands of [Mo₃O₄]⁴⁺ cores at 745–812 cm⁻¹.     

Crystal Structures of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O

Reactions of 1,10‐phenanthroline monohydrate, Na₂C₄H₄O₄ · 6 H₂O and MnSO₄ · H₂O in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] · 2 H₂O ( 1 ) and [Mn(phen)₂(H₂O)₂][Mn(phen)₂(C₄H₄O₄)](C₄H₄O₄) · 7 H₂O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) ų, Z = 1) consists of the dinuclear [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] molecules and hydrogen bonded H₂O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H₂O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) ų, Z = 2) is composed of the [Mn(phen)₂(H₂O)₂]²⁺ cations, [Mn(phen)₂(C₄H₄O₄)] complex molecules, (C₄H₄O₄)^2– anions, and H₂O molecules. The (C₄H₄O₄)^2– anions and H₂O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.     

Alkoholyse von [Fe2(OtBu)6] als einfacher Weg zu neuen Eisen(III)‐Alkoxo‐Verbindungen: Synthesen und Kristallstrukturen von [Fe2(OtAmyl)6], [Fe5OCl(OiPr)12], [Fe5O(OiPr)13], [Fe5O(OiBu)13], [Fe5O(OCH2CF3)13], [Fe5O(OnPr)13] und [Fe9O3(OnPr)21] · iPrOH

Alcoholysis of [Fe₂(O^tBu)₆] as a Simple Route to New Iron(III)‐Alkoxo Compounds: Synthesis and Crystal Structures of [Fe₂(O^tAmyl)₆], [Fe₅OCl(OⁱPr)₁₂], [Fe₅O(OⁱPr)₁₃], [Fe₅O(OⁱBu)₁₃], [Fe₅O(OCH₂CF₃)₁₃], [Fe₅O(OⁿPr)₁₃], and [Fe₉O₃(OⁿPr)₂₁] · ⁿPrOH New alkoxo‐iron compounds can be synthesized easily by alcoholysis of [Fe₂(O^tBu)₆] ( 1 ). Due to different bulkyness of the alcohols used, three different structure types are formed: [Fe₂(OR)₆], [Fe₅O(OR)₁₃] and [Fe₉O₃(OR)₂₁] · ROH. We report synthesis and crystal structures of the compounds [Fe₅OCl(OⁱPr)₁₂] ( 2 ), [Fe₂(O^tAmyl)₆] ( 3 ), [Fe₅O(OⁱPr)₁₃] ( 4 ), [Fe₅O(OⁱBu)₁₃] ( 5 ), [Fe₅O(OCH₂CF₃)₁₃] ( 6 ), [Fe₉O₃(OⁿPr)₂₁] · ⁿPrOH ( 7 ) and [Fe₅O(OⁿPr)₁₃] ( 8 ). Crystallographic Data: 2 , tetragonal, P 4/n, a = 16.070(5) Å, c = 9.831(5) Å, V = 2539(2) ų, Z = 2, d_c = 1.360 gcm^?3, R₁ = 0.0636; 3 , monoclinic, P 2₁/c, a = 10.591(5) Å, b = 10.654(4) Å, c = 16.740(7) Å, β = 104.87(2)°, V = 1826(2) ų, Z = 2, d_c = 1.154 gcm^?3, R₁ = 0.0756; 4 , triclinic, , a = 20.640(3) Å, b = 21.383(3) Å, c = 21.537(3) Å, α = 82.37(1)°, β = 73.15(1)°, γ = 61.75(1)°, V = 8013(2) ų, Z = 6, d_c = 1.322 gcm^?3, R₁ = 0.0412; 5 , tetragonal, P 4cc, a = 13.612(5) Å, c = 36.853(5) Å, V = 6828(4) ų, Z = 4, d_c = 1.079 gcm^?3, R₁ = 0.0609; 6 , triclinic, , a = 12.039(2) Å, b = 12.673(3) Å, c = 19.600(4) Å, α = 93.60(1)°, β = 97.02(1)°, γ = 117.83(1)°, V = 2600(2) ų, Z = 2, d_c = 2.022 gcm^?3, R₁ = 0.0585; 7 , triclinic, , a = 12.989(3) Å, b = 16.750(4) Å, c = 21.644(5) Å, α = 84.69(1)°, β = 86.20(1)°, γ = 77.68(1)°, V = 4576(2) ų, Z = 2, d_c = 1.344 gcm^?3, R₁ = 0.0778; 8 , triclinic, , a = 12.597(5) Å, b = 12.764(5) Å, c = 16.727(7) Å, α = 91.94(1)°, β = 95.61(1)°, γ = 93.24(2)°, V = 2670(2) ų, Z = 2, d_c = 1.323 gcm^?3, R₁ = 0.0594.     

Synthesis and Structural Characterization of a Novel Indium Mercapto Derivative [ClIn(SCH2(CO)O)2]2-[(4-MepyH)2]2+

The synthesis and structural characterization of a novel In(III) complex is described. The reaction between InCl₃ with sodium mercapto-acetic acid (NaSCH₂(CO)OH) in 4-methylpyridine (CH₃(C₅H₅N), (4-Mepy)) at 25°C affords [ClIn(SCH₂(CO)O)₂]^2-[(4-MepyH)₂]²⁺ (1). X-ray diffraction studies of (1) show it to have a distorted square-pyramidal geometry with the [(^-SCH₂(CO)CO^-)] ligands in a trans conformation. The compound crystallizes in the P1(No. 2) space group with a = 7.8624(6) Å, b = 9.950(1) Å, c = 13.793(2) Å, α = 107.60(1)°, β = 90.336(8)°, γ = 98.983(9)°, V = 1014.3(4) ų, R(F°) = 0.037 and R_w = 0.048.     

Syntheses of Monomeric,Dimeric, and Trimeric Complexes of Tungsten(VI), (V), (IV), and (III) with the 1,4,7-Triazacyclononane (L) Ligand. Crystal Structures of Dimeric [W2L2(μ2?OH)2Br2]Br2 · 2H2O and of Trimeric [W3L3(μ3?0)(μ2-0)3][ZnBr4]2

Reactions of WL(CO)₃ (L = 1, 4, 7-triazacyclononane; C₆H₁₅N₃) with bromine under different conditions afford the monomeric W^VI compound, WO₂LBr₂, or the monomeric W^V complex, WOLBr₃. The former dimerizes in aqueous solution, yielding the [W₂O₅L₂]²⁺ cation. Two diamagnetic isomers of the W^V -dimer, [W₂O₄L₂]²⁺, have been prepared : a yellow form with terminal oxo groups in cis-positions with respect to each other and a red species containing two terminal oxo-groups in trans-positions. The cationic W^IV -trinuclear cluster, [W₃O₄L₃]⁴⁺, has been isolated as the tetrabromozincate(2-) salt and its structure has been determined by single crystal X-ray diffraction. [W₃O₄L₃][ZnBr₄]₂ crystallizes in the monoclinic space group P2₁/c with a = 12.698(2) Å, b = 21.267(6) Å, c = 15.687(7) Å, β = 92.94(3)⁰, and V = 4222 ų, d_ealed. = 2.79 g cm^?3 for Z = 4, and mol wt 1773.2. The structure was solved by direct methods using 7399 unique reflections with I≥ 2.5 σ (I). Final residuals were R₁ = 0.089 and R₂ = 0.096. The structure consists of [W₃L₃O₄]⁴⁺ cations of the M₃X₁₃ cluster type and isolated ZnBr₄^2? anions. Three tungsten atoms occupy the corners of an equilateral triangle bridged by three μ₂-oxo- and one μ₃-oxo-ligands; each tungsten atom has a distorted octahedral environment of three oxygen and three nitrogen atoms. The short W - W distances of 2,52 Å and the diamagnetism indicate metal-metal bonding. The green, diamagnetic binuclear W_III complex, [W₂L₂(μ? OH)₂Br₂]Br₂ · 2 H₂O, has been prepared by reduction of monomeric WLOBr₃ in strongly acidic solution with zinc powder. The complex has been characterized by a single-crystal X-ray diffraction study; it crystallized in the orthorhombic space group Pnnm with a = 13.837(5) Å, b = 11.657(6) Å, c = 7.832 Å, and V = 1263 ų, d_calcd. = 2.67 g cm^?3 for Z = 2, and mol wt 1015.8. The structure was solved by direct methods using 783 unique reflections with I ? 2.5 σ(1). Final residuals were R₁ = 0.062 and R₂ = 0.084. The structure consists of dimeric cations [W₂L₂(μ? OH)₂Br₂]²⁺, bromide anions and molecules of water of crystallization. The tungsten centers are in a distorted octahedral environment of the tridentate N-donor igand, one coordinated bromide and two μ₂-hydroxo bridges (edge sharing), respectively. The bromide ligands are in trans-positions with respect to each other. The four-membered W₂(μ? OH)₂ ring is planar. The W? W distance of 2.477(3) Å together with its diamagnetism imply the presence of a strong metal-metal bond between the tungsten(II1) centers (σ²π²δ²).     

Beiträge zum Koordinationsverhalten von Oxidionen in anorganischen Feststoffen. III [1] Mn2P2O7, Mn2P4O12 und Mn2Si(P2O7)2 — Kristallzüchtung,Strukturverfeinerungen und Elektronenspektren von Mangan(II)‐Phosphaten

Contributions on the Bonding Behaviour of Oxygen in Inorganic Solids. III [1] Mn₂P₂O₇, Mn₂P₄O₁₂ und Mn₂Si(P₂O₇)₂ — Crystal Growth, Structure Refinements and Electronic Spectra of Manganese(II) Phosphates By chemical vapour transport reactions in a temperature gradient single crystals of Mn₂P₂O₇ (1050 → 950 °C) and Mn₂P₄O₁₂ (850 → 750 °C) have been obtained using P/I mixtures as transport agent. Mn₂Si(P₂O₇)₂ was crystallized by isothermal heating (850 °C, 8d; NH₄Cl as mineralizer) of Mn₂P₄O₁₂ und SiO₂. In Mn₂Si(P₂O₇)₂ [C 2/c, a = 17.072(1)Å, b = 5.0450(4)Å, c = 12.3880(9)Å, β = 103.55(9)°, 1052 independent reflections, 97 variables, R1 = 0.023, wR2 = 0.061] the Mn²⁺ ions show compressed octahedral coordination (d¯_Mn—O = 2.19Å). The mean distance d¯_Mn—O = 2.18Å was found for the radially distorted octahedra [MnO₆] in Mn₂P₄O₁₂ [C 2/c, Z = 4, a = 12.065(1)Å, b = 8.468(1)Å, c = 10.170(1)Å, β = 119.29(1)°, 2811 independent reflections, 85 variables, R1 = 0.025, wR2 = 0.072]. Powder reflectance spectra of the three pink coloured manganese(II) phosphates have been measured. The spectra show clearly the influence of the low‐symmetry ligand fields around Mn²⁺. Observed d—d electronic transition energies and the results of calculations within the framework of the angular overlap model (AOM) are in good agreement. Bonding parameters for the manganese‐oxygen interaction in [Mn²⁺O₆] chromophors as obtained from the AOM treatment (B, C, Trees correction α, e_σ, e_π) are discussed.     

Synthesis and Crystal Structure of SrFe[BP2O8(OH)2]

SrFe[BP₂O₈(OH)₂] was synthesised under mild hydrothermal conditions. The crystal structure was determined from single–crystal X–ray diffraction data: triclinic, space group P (No. 2), a = 6.6704(12) Å, b = 6.6927(13) Å, c = 9.3891(19) Å, α = 109.829(5)°, β = 102.068(6)°, γ = 103.151(3)°, V = 364.74(12) ų and Z = 2. The crystal structure of SrFe[BP₂O₈(OH)₂] contains isolated borophosphate oligomers, [BP₂O₈(OH)₂]^5–, which are interconnected by Fe^IIIO₄(OH)₂ coordination octahedra. The resulting three–dimensional framework is characterised by elliptical channels running along [011]. Strontium takes positions inside the channels.     

Syntheses and crystal structures of two cadmium coordination polymers [Cd(2-mBIM)(NCS)(SCN)] n and [Cd2(2-mBIM)2(NO3)2(C4H4O4)(H2O)5] n based on bis(2-methylimidazol-1-yl)methane

Two cadmium(II) coordination polymers, [Cd(2-mBIM)(NCS)(SCN)] _n (1) and [Cd₂(2-mBIM)₂(NO₃)₂(C₄H₄O₄)(H₂O)₅] _n (2) (2-mBIM = bis(2-methylimidazo-1-yl)methane, C₄H₄O₄= succinate), have been synthesized and characterized by X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1 with a = 9.0770(5) Å, b = 9.4043(4) Å, c = 19.8720(9) Å, α = 101.551(1)°, β = 93.498(1)°, γ = 108.484(1)°, V = 1562.02(13) ų, and Z = 2. Each Cd(II) is octahedrally coordinated and connected with two adjacent Cd(II)'s by double end-to-end thiocyanate bridges, resulting in the formation of 1-D zigzag chains, linked to each other via bridging 2-mBIM giving a 2-D supramolecular framework. Complex 2 crystallizes in the monoclinic space group P2(1)/n with a = 12.6543(6) Å, b = 7.7128(4) Å, c = 17.3089(9) Å, β = 109.3980(10)°, V = 1593.45(14) ų, and Z = 2. Cd(II) is coordinated with oxygen and nitrogens from two independent 2-mBIM, in a cis-configuration to form a 1-D helical structure. A 3-D supramolecular network comprised of succinate anion bridged 1-D helical chains, and weak hydrogen bonds between dimer waters gave 2-D layers.     

A new route to prepare the mixed oxo-ethylidyne-capped trinuclear tungsten(IV) cluster and the crystal structure of H2Na3[W3O(CCH3)-(O2CCH3)6(H2O)3][H2W12O40]·13.5H2O

The synthesis and the structural characterization of the title compound H₂Na₃[W₃O(CCH₃)-(O₂CCH₃)₆(H₂O)₃][H₂W₁₂O₄₀]·13.5H₂O are described. It is known that the mixed oxo-ethylidynecapped tritungsten cluster can be obtained by Zn dust reduction of Na₂WO₄·2H₂O in acetic anhydride. The title compound has been characterized by X-ray diffraction, UV/VIS and ¹H NMR spectra. The tungsten atoms in the cluster cation and anion are in the oxidation states of W(IV) and W(VI) respectively. The crystal is rhombohedral with the space group R32, a = 17.058 (3)Å, c = 49.665 (9)Å, γ=120°, V=12516(9)ų, Z=6, final R = 0.037 for 2071 reflections with I ≥3σ (I). Both the cluster cation and anion have a C₃ symmetry. The important interatomic distances in angstroms for the cluster cation are: W—W, 2.730(2); W—μ₃?O, 2.00; W—O (carboxy1), 2.12; W—O_t 2.18 (2).     

Synthesis and characterization of a new transition-metal complex of the Lindqvist polyanion Na[Cu(1, 3-pda)2]3[HNb6O19] · 3H2O

A new transition-metal (TM) complex of the Lindqvist polyanion Na[Cu(1, 3-pda)₂]₃[HNb₆O₁₉] · 3H₂O (1, 3-pda = 1, 3-diaminopropane) has been prepared using pre-prepared TBA₄[H₄Nb₆O₁₉] · 7H₂O as a precursor and characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, and thermogravimetric analysis. Crystal data for the compound: rhombohedral, space group R-3c, a = 14.927(4) Å, b = 14.927(4) Å, c = 36.940(18) Å, γ = 120°, V = 7128(4) ų, Z = 6. The structural unit of the title compound consists of a polyanion [HNb₆O₁₉]^7?, a Na⁺, three [Cu(1, 3-pda)₂]²⁺, and three crystal water molecules. The occupancy of all Cu atoms and water molecules is 0.5. X-ray diffraction indicated that the cations and the polyanion were linked through electrostatic interactions and intermolecular forces.     

Synthesis and crystal structure of new sodium oxothiocyanofluoroantimonate(III) Na2Sb5F9O3(NCS)2

Na₂Sb₅F₉O₃(NCS)₂, a new complex, has been synthesized from NaSCN and SbF₃ aqueous solutions and studied by chemical, X-ray diffraction, and thermal analyses and IR, ^121,123Sb NQR, and ¹⁹F NMR spectroscopy. Its layered structure (triclinic symmetry system, a = 6.9998(1) Å, b = 9.4180(1) Å, c = 13.1094(2) Å, α = 74.815(1)°, β = 78.188(1)°, γ = 82.779(1)°, Z = 2, space group P $\bar 1$ ) is built of Na⁺ cations and [Sb₁₀F₁₈O₆(NCS)₄]^4? decanuclear complex anions that consist of two [Sb₅F₉O₃(NCS)₂]^2? pentanuclear complex anions linked by two weak Sb-F ionic bonds (2.529(2) Å). Decanuclear complex anions are linked into layers by secondary Sb…F bonds and Na-F bonds. Van der Waals interactions link these layers into a framework. The complex is stable up to 200°C.     

Neue Halogenochalkogen(IV)‐Säuren: [H3O(Benzo‐18‐Krone‐6)]2[Te2Br10] und [H5O2(Dibenzo‐24‐Krone‐8)]2[Te2Br10]

Novel Halogenochalcogeno(IV) Acids: [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] Systematic studies on halogenochalcogeno(IV) acids containing tellurium and bromine led to the new crystalline phases [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] ( 1 ) and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] ( 2 ). The [Te₂Br₁₀]^2‐ anions consists of two edge‐sharing distorted TeBr₆ octahedra, the oxonium cations are stabilized by crownether. ( 1 ) crystallizes in the monoclinic space group P2₁/n with a = 14.520(5) Å, b = 22.259(6) Å, c = 16.053(5) Å, β = 97.76(3)° and Z = 4, whereas ( 2 ) crystallizes in the triclinic space group with a = 11.005(4) Å, b = 12.103(5) Å, c = 14.951(6) Å, α = 71.61(3)°, β = 69.17(3)°, γ = 68.40(3)° and Z = 1.     

Synthesis and Crystal Structure of [C10N2H10]2[P2Mo5O21(OH)2]·2H2O

The crystal structure of [C₁₀N₂H₁₀]₂[P₂Mo₅O₂₁(OH)₂] · 2H₂O, contains the heteropolyanion, [P₂Mo₅O₂₁(OH)₂]^4—, together with diprotonated 4, 4′‐bipyridine. The heteropolyanion is built up from five MoO₆ octahedra sharing four common edges and one common corner, capped by two PO₃(OH) tetrahedra. The structure is stabilized by hydrogen bonds involving the hydrogen atoms of the 4, 4′‐bipyridine, water molecules and the oxygen atoms of the pentamolybdatobisphosphate. This is the first example that this kind of cluster could be isolated in the presence of a poly‐functional aromatic molecule ion. Crystal data: triclinic, P1¯ (No. 2), a = 9.983(2)Å, b = 11.269(2)Å, c = 17.604(4)Å, α = 73.50(3)°, β = 84.07(3)°, γ = 67.96(3)°; V = 1760.0(6)ų; Z = 2; R₁ = 0.037 and wR₂ = 0.081, for 9138 reflections [I > 2σ(I)].     

Synthesis and Crystal Structure of Pb3O2(SeO3)

Single crystals of Pb₃O₂(SeO₃) have been prepared hydrothermally at 230 °C. The structure (orthorhombic, Cmc2₁, a = 10.529(2), b = 10.722(2), c = 5.7527(12)Å, V = 649.5(2)ų) has been solved by direct methods and refined to R₁ = 0.059 on the basis of 615 unique observed reflections (|F_o| = 4σ_F). The structure is based upon double [O₂Pb₃]²⁺ chains of edge‐sharing [OPb₄]⁶⁺ tetrahedra. These [O₂Pb₃]²⁺ chains run parallel to [001], and their planes are parallel to (010). The pyramidal (SeO₃)^2— anions are located between the chains; their triangular oxygen atom bases lie parallel to (001) and all (SeO₃)^2— groups are pointing in the same direction. A short compilation of [O₂M₃] chains of oxocentred M₄ tetrahedra in minerals and inorganic compounds is provided.     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

The Sodium (Iso)Cyanurates Nax[H3–xC3N3O3]·yH2O (x = 1–3, y = 0, 1): A Key‐Series for Understanding the Crystal Chemistry of Metal (Iso)Cyanurates

The (iso)cyanurates Na[H₂C₃N₃O₃] · H₂O, Na₂[HC₃N₃O₃] · H₂O, Na₂[HC₃N₃O₃], and Na₃[C₃N₃O₃] were synthesized phase pure from Na₂CO₃ · 10H₂O, NaOH, and cyanuric acid, respectively, in aqueous solution by carefully adjusting the crystallization conditions. The crystal structures of all compounds were determined by single‐crystal X‐ray diffraction {Na₂[HC₃N₃O₃] · H₂O: P1 , a = 3.51660(10) Å, b = 7.8300(3) Å, c = 11.3966(4) Å, α = 86.4400(10)°, β = 85.5350(10)°, γ = 85.0720(10)°, Z = 2, R₁ = 0.030, wR₂ = 0.078; Na₂[HC₃N₃O₃]: Pnma, a = 6.3409(6) Å, b = 12.2382(13) Å, c = 6.5919(7) Å, Z = 4, R₁ = 0.045, wR₂ = 0.079; Na₃[C₃N₃O₃]: R3 c, a = 11.7459(3) Å, c = 6.5286(3) Å, Z = 3, R₁ = 0.039, wR₂ = 0.066}. The structures show ribbons (Na[H₂C₃N₃O₃] · H₂O), dimers (Na₂[HC₃N₃O₃] · H₂O), chains (Na₂[HC₃N₃O₃]), or columns (Na₃[C₃N₃O₃]) of hydrogen‐bonded and parallel stacked (iso)cyanurate anions. These motifs are shown to be characteristic for certain degrees of protonation and hydration, and all (iso)cyanurate crystal structures found so far were classified accordingly. X‐ray powder patterns, thermogravimetry curves, IR and UV/Vis spectra were measured for all compounds.     

Crystal Structure of the B‐type Dierbium Oxide ortho‐Oxosilicate Er2O[SiO4]

The crystal structure of B‐type Er₂O[SiO₄] has been determined by single crystal X‐ray diffraction. It crystallizes with the (Mn,Fe)₂[PO₄]F type structure in the monoclinic space group C2/c (a = 14.366(2), b = 6.6976(6), c = 10.3633(16) Å, ß = 122.219(10)°, Z = 8) and shows anionic tetrahedral [SiO₄]^4– units and non‐silicon‐bonded O^2– anions in distorted [OEr₄]¹⁰⁺ tetrahedra. The [(Er1)O₆₊₁] and [(Er2)O₆] polyhedra form infinite chains which are connected by common edges.     

Na6Si2O7 – The Missing Structural Link among Alkali Pyrosilicates

The crystal structure of sodium pyrosilicate (Na₆Si₂O₇) was solved from single crystal diffraction data and refined to an R index of 0.051 for 17034 independent reflections. The compound is triclinic with space group P (a = 5.8007(8) Å, b = 11.5811(15) Å, c = 23.157(3) Å, α = 89.709(10)°, β = 88.915(11)°, γ = 89.004(11)°, V = 1555.1(4) Å³, Z = 8, D_x = 2.615 g · cm^–3, μ(Mo‐K_α) = 7.94 cm^–1). A characteristic feature of the crystals is a twinning by reticular pseudo‐merohedry, which simulates a much larger monoclinic C centered lattice (V′ = 6220 Å³, Z = 32). The twin element corresponds to a twofold rotation axis running parallel to the [0 direction of the triclinic cell. The compound belongs to the group of sorosilicates, i.e. it is based on [Si₂O₇] groups, which are arranged in layers parallel to (100). Charge compensation within the structure is accomplished by monovalent sodium cations distributed among 24 crystallographically independent positions. They are coordinated by four to six nearest oxygen neighbors. Most of the coordination polyhedra can be approximately described as distorted tetrahedra or tetragonal pyramids. An alternative understanding of Na₆Si₂O₇ can be gained if the tetrahedrally coordinated sodium atoms are considered for the construction of a framework. Actually, each four of the dimers within a single slice are linked by a more or less distorted [NaO₄] tetrahedron. The resulting structural motif is similar to the one that can be observed in melilites, where linkage between the T₂O₇ (T: Al, Si) moieties is provided by [MgO₄]‐ (as in akermanite, Ca₂Mg[Si₂O₇]) or [AlO₄] tetrahedra (as in gehlenite, Ca₂Al[AlSiO₇]). By sharing common edges, the [NaO₄] tetrahedra in Na₆Si₂O₇ are forming columns running parallel to 25 . The resulting framework contains tunnels in which the more irregularly coordinated sodium cations are incorporated.