Zur Kenntnis der Hydrate M(HSeO3)2 · 4H2O (M = Mg,Co, Ni,Zn). Röntgenstrukturanalytische,schwingungsspektroskopische und thermoanalytische Untersuchungen

On the Hydrates M(HSeO₃)₂ · 4H₂O (M = Mg, Co, Ni, Zn) – Crystal Structures, IR, Raman, and Thermoanalytical Investigations From aqueous solutions of M(HSeO₃)₂ single crystals of Mg(HSeO₃)₂ · 4H₂O and of the hitherto unknown compounds Co(HSeO₃)₂ · 4H₂O, Ni(HSeO₃)₂ · 4H₂O and Zn(HSeO₃)₂ · 4H₂O could be obtained. The crystal structures, X-ray powder, IR, Raman and thermoanalytical (DTA, TG, Raman heating) data are presented and discussed. The crystal data of the isotypic compounds are: monoclinic, space group C2/c, Z = 4, Mg: a = 1 464.6(2), b = 755.3(1), c = 1 099.9(1) pm, β = 126.59(1)°, V = 0.9769(1) nm³, Co: a = 1 462.5(2), b = 756.5(2), c = 1 102.2(2) pm, β = 126.53(1)°, V = 0.9798(2) nm³, Ni: a = 1 452.2(2), b = 751.0(1), c = 1 091.5(1) pm, β = 126.28(1)°, V = 0.9595(1) nm³, Zn: a = 1 468.3(2), b = 755.8(1), c = 1 103.1(1) pm, β = 126.79(1)°, V = 0.9804(2) nm³. The crystal structures consist of hexagonal packed [M(HSeO₃)₂ · 2H₂O]_n chains of [MO₄(H₂O)₂] octahedra linked by Se atoms. They contain trigonal pyramidal SeO₂OH^?ions with “free” hydroxyl groups and also “free” molecules of water of crystallization. The hydroxyl groups build strong H-bonds (O? H …? O distances: 265–268 pm). The IR spectra show AB doublett bands in the OH stretching mode region of the hydroxyl groups. The water molecules of crystallization are linked to planar (H₂O)₄ tetramers by H-bonds with unusually short O? H …? O bond distances of 271–273 pm. DTA and TG measurements indicate that thermal decomposition results in the direct formation of the respective diselenite MSe₂O₅. Raman heating measurements show under quasi static conditions the intermediate formation of the anhydrous hydrogen selenites.     

Darstellung,Kristallstruktur und IR‐Spektren von BeSeO3 · H2O – Wasserstoffbrücken und Korrelation von IR‐ und Strukturdaten in den Monohydraten MSeO3 · H2O (M = Be,Ca, Mn,Co, Ni,Zn, Cd)

Preparation, Crystal Structure and IR Spectra of BeSeO₃ · H₂O – Hydrogen Bonds and Correlation of IR and Structure Data in the Monohydrates MSeO₃ · H₂O (M = Be, Ca, Mn, Co, Ni, Zn, Cd) BeSeO₃ · H₂O (oP32) has been obtained by treating amorphous BeSeO₃ · 4 H₂O precipitated from Be(HSeO₃)₂ solutions hydrothermally at 150 °C. The crystal structure (P2₁2₁2₁, a = 560.59(4), b = 755.25(5), c = 781.14(5) pm, Z = 4, D_X = 3.092 gcm^–3, R = 0.018 for the 2034 reflections with I > 2σ_I of the enantiomer investigated) contains BeO₃(H₂O) tetrahedra built up from three selenite and one water oxygen atoms. The BeO₃(H₂O) tetrahedra are 3 D‐connected via Se atoms of trigonal pyramidal SeO₃^2– ions. The Be–O distances are 161.8 to 164.4 pm. The Se–O bond lenghts (169.2–170.3 pm) and the O–Se–O bond angles (98.1–101.4°) are normal. The water molecules of crystallization form together with the SeO₃^2– ions screw‐like hydrogen bond systems along [100]. Despite the strong synergetic effect of the Be²⁺ ions, the hydrogen bonds (d(OH…O) = 267.4 and 276.4 pm, respectively; ν_OD of matrix isolated HDO molecules: 2244 and 2405 cm^–1, respectively) are normal compared to other neutral selenite hydrates. Together with the hitherto known monohydrates M^IISeO₃ · H₂O and other beryllium salt hydrates, the hydrogen bonds of BeSeO₃ · H₂O are discussed with regard to their geometry and IR spectroscopy.     

Synthesis and Crystal Structure of Cesium Nitratometalates(II), Cs2[M(NO3)4] (M = Mn,Co, Ni,Zn)

Crystalline cesium nitratometalates(II), Cs₂[M(NO₃)₄] (M = Mn ( I ), Co ( II ), Ni ( III ), and Zn ( IV )) were synthesized from M(NO₃)₂ · n H₂O and CsNO₃ by heating at 80–120 °C over 10–12 h. According to X-ray crystal structure analysis, the compounds are built from Cs⁺ cations and [M(NO₃)₄]^2– anions. The latter differ by the type of metal coordination: a dodecahedron for Mn in I (CN = 8, r_Mn–O 2.24–2.37 Å), a seven coordination for Co in II (CN = 4 + 3, r_Co–O 2.03–2.16 Å and 2.21–2.35 Å) and a tetrahedral distorted dodecahedron for Zn in IV (CN = 4 + 4, r_Zn–O 1.98–2.15 Å and 2.38–2.72 Å). Ni atom in III has a distorted octahedral NiO₆ environment provided by two unidentate and two bidentate NO₃ groups with Ni–O distances of 2.01–2.14 Å. The differences in metal coordination are discussed in terms of valence electron configurations, ionic radii, and the packing effects.     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

IR- und Raman-Spektren der isotypen Iodathydrate M(IO3)2 · 4 H2O (M = Mg,Ni, Co); Kristallstruktur von Co(IO3)2 · 4 H2O

Infrared and Raman Spectroscopy of the Isostructural Iodate Hydrates M(IO₃)₂ · 4 H₂O (M = Mg, Ni, Co)-Crystal Structure of Cobalt Iodate Tetrahydrate The iodate tetrahydrates Mg(IO₃)₂ · 4 H₂O, β-Ni(IO₃)₂ · 4 H₂O, Co(IO₃)₂ · 4 H₂O and their deuterated specimens were studied by X-ray, infrared and Raman spectroscopic methods. The title compounds are isostructural crystallising in the monoclinic space group P2₁/c (Z = 2). The crystal structure of Co(IO₃)₂ · 4 H₂O (a = 836.8(5), b = 656.2(3), c = 850.2(5) pm and β = 100.12(5)°) has been refined by single-crystal X-ray methods (R_obs = 3.08%, 693 unique reflections I₀ > 2σ(I)). Isolated Co(IO₃)₂(H₂O)₄ octahedra form layers parallel (100). Within these layers, the two crystallographically different hydrate water molecules form nearly linear hydrogen bonds to adjacent IO₃^– ions (ν_OD of matrix isolated HDO of Co(IO₃)₂ · 4 H₂O (isotopically diluted samples) 2443 (H3), 2430 (H2), and 2379 cm^–1 (H1 and H4), –180 °C). Intramolecular O–H and intermolecular H…O distances were derived from the novel ν_OD vs. r_OH and the traditional ν_OD vs. r_H…O correlation curves, respectively. The internal modes of the iodate ions of the title compounds are discussed with respect to their coupling with the librations of the hydrate H₂O molecules, the distortion of the IO₃^– ions, and the influence of the lattice potential.     

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.     

Kristallstrukturen und thermisches Verhalten von Metalldihydrogenphosphat‐HF‐Addukten MH2PO4 · HF (M = K,Rb, Cs) mit Wasserstoffbrückenbindungen vom Typ F–H…O

Structures and Thermal Behaviour of Alkali Metal Dihydrogen Phosphate HF Adducts, MH₂PO₄ · HF (M = K, Rb, Cs), with Hydrogen Bonds of the F–H…O Type Three HF adducts of alkali metal dihydrogen phosphates, MH₂PO₄ · HF (M = K, Rb, Cs), have been isolated from fluoroacidic solutions of MH₂PO₄. KH₂PO₄ · HF crystallizes monoclinic: P2₁/c, a = 6,459(2), b = 7,572(2), c = 9,457(3) Å, β = 101,35(3)°, V = 453,5(3) ų, Z = 4. RbH₂PO₄ · HF and CsH₂PO₄ · HF are orthorhombic: Pna2₁, a = 9,055(3), b = 4,635(2), c = 11,908(4) Å, V = 499,8(3) ų, Z = 4, and Pbca, a = 7,859(3), b = 9,519(4), c = 14,744(5) Å, V = 1102,5(7) ų, Z = 8, respectively. The crystal structures of MH₂PO₄ · HF contain M⁺ cations, H₂PO₄^– anions and neutral HF molecules. The H₂PO₄^– anions are connected to layers by O–H…O hydrogen bonds (2,53–2,63 Å), whereas the HF molecules are attached to the layers via very short hydrogen bonds of the F‐H…O type (2,36–2,38 Å). The thermal decomposition of the adducts proceeds in three steps. The first step corresponds to the release of mainly HF and a smaller quantity of water. In the second and third steps, water evolution caused by condensation of dihydrogen phosphate is the dominating process whereas smaller amounts of HF are also released.     

Crystal Structures of [Mn2(H2O)4(bpy)2(C8H12O4)2] · 2 H2O and [Mn(H2O)2(bpy)(C8H12O4)2/2] · H2O with bpy = 2,2′‐bipyridine

Reaction of MnSO₄ · H₂O, 2,2′‐bipyridine (bpy), suberic acid and Na₂CO₃ in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] · 2 H₂O ( 1 ) and [Mn(H₂O)₂‐ (bpy)(C₈H₁₂O₄)_2/2] · H₂O ( 2 ). In both complexes, the Mn atoms are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two trans positioned H₂O molecules and two suberato ligands (d(Mn–O) = 2.107–2.328 Å; d(Mn–N) = 2.250–2.330 Å). The bis‐monodentate suberato ligands bridge Mn atoms to form dinuclear [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] complex molecules in 1 and 1D [Mn(H₂O)₂(bpy)(C₈H₁₂O₄)_2/2] chains in 2 . Via the intermolecular hydrogen bondings and π‐π stacking interactions, the dinuclear molecules in 1 are assembled into 2D networks parallel to (100), between which the crystal H₂O molecules are sandwiched. The polymeric chains in 2 are linked together by interchain hydrogen bonding and π‐π stacking interactions into 3D networks with the crystal H₂O molecules located in tunnels along [010]. Crystal data for 1 : P2₁/c (no. 14), a = 10.092(1) Å, b = 11.916(2) Å, c = 17.296(2) Å, β = 93.41(1)° and Z = 2. Crystal data for 2 : P2₁/c (no. 14), a = 11.176(2) Å, b = 9.688(1) Å, c = 37.842(6) Å, β = 90.06(1)° and Z = 8.     

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.     

Hydrogensulfate mit fehlgeordneten Wasserstoffatomen – Synthese und Struktur von Li[H(HSO4)2](H2SO4)2 sowie Verfeinerung der Struktur von α-NaHSO4

Hydrogen Sulfates with Disordered Hydrogen Atoms – Synthesis and Structure of Li[H(HSO₄)₂](H₂SO₄)₂ and Refinement of the Structure of α-NaHSO₄ The structure of Li[H(HSO₄)₂](H₂SO₄)₂ has been determined for the first time whereas the structure of α-NaHSO₄ has been refined, so that direct determination of the hydrogen positions was possible. Both compounds crystallize triclinic in the space group P1 with the lattice constants a = 6.708(2), b = 6.995(1), c = 7.114(1) Å, α = 75.53(1), β = 84.09(2) and γ = 87.57(2)° (Z = 4) for α-NaHSO₄ and a = 4.915(1), b = 7.313(1), c = 8.346(2) Å, α = 82.42(3), β = 86.10(3) and γ = 80.93(3)° (Z = 1) for Li[H(HSO₄)₂](H₂SO₄)₂. In both compounds there are disordered hydrogen positions. In the structure of α-NaHSO₄ there are two crystallographically different HSO₄^? tetrahedra and two different coordinated Na atoms. The system of hydrogen bonds can be described by chains in [0–11] direction. The disordering of the H atoms reduces the differences between the S? O and S? OH distances (1.45 and 1.50 Å) while in the ordered HSO₄ unit “regular” bond lengths are observed (1.45 und 1,57 Å). In the structure of Li[H(HSO₄)₂](H₂SO₄)₂ there are two crystallographically different SO₄-tetrahedra. The first one belongs to the [H(HSO₄)₂]^? unit while the second one represents H₂SO₄ molecules. The H atom which is located nearby the symmetry centre and connects two HSO₄ units by a short O…?O distance of 2.44 Å. Li is located on a symmetry centre and is slightly distorted octahedrally coordinated by oxygen atoms of six different SO₄ tetrahedra. The system of hydrogen bonds can be regarded as consisting of double layers parallel to the xy-plane.     

Synthese und Kristallstruktur von Hydrogensulfaten einwertiger Metalle – Ag(H3O)(HSO4)2, Ag2(HSO4)2(H2SO4), AgHSO4 und Hg2(HSO4)2

Synthesis and Crystal Structure of Metal(I) Hydrogen Sulfates – Ag(H₃O)(HSO₄)₂, Ag₂(HSO₄)₂(H₂SO₄), AgHSO₄, and Hg₂(HSO₄)₂ Hydrogen sulfates Ag(H₃O)(HSO₄)₂, Ag₂(HSO₄)₂ · (H₂SO₄), and AgHSO₄ have been synthesized from Ag₂SO₄ and sulfuric acid. Hg₂(HSO₄)₂ was obtained from metallic mercury and 96% sulfuric acid as starting materials. The compounds were characterized by X‐ray single crystal structure determination. Ag(H₃O)(HSO₄)₂ belongs to the structure type of Na(H₃O)(HSO₄). The silver atom is coordinated by 6 + 2 oxygen atoms. In the structure, there are dimers and chains of hydrogen bonded HSO₄^– tetrahedra. Dimers and chains are connected by the H₃O⁺ ion to form a three dimensional hydrogen network. Ag₂(HSO₄)₂(H₂SO₄) crystallizes isotypic to Na₂(HSO₄)₂(H₂SO₄). The coordination number of silver is 6 + 1. The structure of Ag₂(HSO₄)₂(H₂SO₄) is characterized by hydrogen bonded trimers of HSO₄^– tetrahedra, which are further connected to chains. For the recently published structure of AgHSO₄ the hydrogen bonding system was discussed. There are tetrameres and chains, connected by bifurcated hydrogen bonds. The structure of Hg₂(HSO₄)₂ contains Hg₂²⁺ cations with Hg–Hg distance of 2.509 Å. Every mercury atom is coordinated by one oxygen atom at shorter distance (2.18 Å) and three ones at longer distances (2.57 to 3.08 Å). The HSO₄^– tetrahedra form zigzag chains by hydrogen bonds.     

A New Succinato‐bridged Supramolecular Helix Chain: Crystal Structure of [Mn(H2O)2(bpy)(C4H4O4)] · H2O with bpy = 2,2′‐bipyridine

Yellow crystals of [Mn(H₂O)₂(bpy)(C₄H₄O₄)] · H₂O were obtained by the reaction of 2,2′‐bipyridine, succinic acid, MnSO₄ · H₂O and Na₂CO₃ in an aqueous methanol solution. The crystal structure (monoclinic, P2₁/c (no. 14), a = 8.294(1), b = 11.556(1), c = 17.064(1)Å, β = 95.181(6)°, Z = 4, R = 0.0349, wR² = 0.0887) consists of 1D supramolecular helix chains [Mn(H₂O)₂(bpy)(C₄H₄O₄)_2/2] and hydrogen bonded H₂O molecules. The Mn atoms are octahedrally coordinated by two N atoms of one bidentate chelating bpy ligand and four O atoms of two H₂O molecules and two bis‐monodentate bridging succinato ligands with d(Mn–O) = 2.139–2.237Å and d(Mn–N) = 2.268, 2.281 Å. The helix chains are held together by π‐π stacking interactions and hydrogen bonds.     

Synthese,Kristallstruktur und thermischer Abbau von Fluoroaluminaten der Zusammensetzung (NH4)[M(H2O)6][AlF6] (M = Zn,Ni), [Zn(H2O)6][AlF5(H2O)] und (PyH)4[Al2F10] · 4 H2O

Synthesis, Crystal Structure and Thermal Behaviour of Fluoroaluminates of the Composition (NH₄)[M(H₂O)₆](AlF₆) (M = Zn, Ni), [Zn(H₂O)₆][AlF₅(H₂O)], and (PyH)₄[Al₂F₁₀] · 4 H₂O Four new fluoroaluminates were obtained from fluoroacidic solutions of respective metal salts. The compounds of zinc ( I a : P2₁/c, a = 12.688(3), b = 6.554(1), c = 12.697(3) Å, β = 95.21(3)°, V = 1051.5(4) ų, Z = 4) and nickel ( I b : P2₁/c, a = 12.685(3), b = 6.517(1), c = 12.664(2)Å, β = 94.55(2)°, V = 1043.6(4) ų, Z = 4) are isotypic and represent a new structure type consisting of two different cations, NH₄⁺ and [M(H₂O)₆]²⁺ and [AlF₆]^3–‐anions. [Zn(H₂O)₆][AlF₅(H₂O)] ( II : C2/m, a = 10.769(2), b = 13.747(3), c = 6.487(1)Å, β = 100.02(3)°, V = 945.7(3) ų, Z = 4) is characterized by a H₂O/F‐disorder in the [AlF₅(H₂O)]‐octahedra in two trans positions. In (PyH)₄[Al₂F₁₀] · 4 H₂O ( III : Cmc2₁, a = 15.035(3), b = 20.098(4), c = 12.750(4) Å, V = 5364(2) ų, Z = 8), bioctahedral [Al₂F₁₀]^4– anions have been found for the first time. The structures are described and discussed in comparison. The new compounds were used as precursors in order to obtain new AlF₃‐phases. However, the thermal decomposition did not result in the formation of any new metastable AlF₃‐phase. Instead, phase mixtures of either α‐AlF₃ and β‐AlF₃ or AlF₃ and MF₂ were obtained.     

Triphenylphosphinoxid (L) als Solvens und Ligand für Metallphthalocyaninate; Synthese und Struktur von [{Li(L)}2(μ‐pc)], [Li(L)4][Lipc] · Solvat, [Mg(L)pc] · Solvat und [Zn(L)pc] · Solvat

Triphenylphosphine Oxide (L) as Solvent and Ligand for Metallophthalocyaninates; Synthesis and Structure of [{Li(L)}₂(μ‐pc)], [Li(L)₄][Lipc] · Solvate, [Mg(L)pc] · Solvate, and [Zn(L)pc] · Solvate Triphenylphosphine oxide (L) coordinates to metallophthalocyaninates of Li, Mg and Zn at 300 °C. After purification and recrystallization in different solvents the very soluble and stable title compounds have been isolated and structurally characterized. In [{Li(L)}₂(μ‐pc)], the Li atom lies in a distorted tetragonal pyramid of four isoindole N atoms (N_i) at a distance varying between 2.163(5) and 2.301(5) Å, and an O atom at 1.863(5) Å. In [Li(L)₄] · [Lipc] · S, the Li atom of the cation coordinates four O atoms in a distorted tetrahedral arrangement at a distance varying from 1.887(9) to 1.953(9) Å, while the Li atom of the anion is in a quasi quadratic planar geometry of four N_i atoms (1.951(9)–1.977(9) Å) with the Li atom being displaced by 0.15 Å out of the (N_i)₄ plane. The structural data of the distorted tetragonal pyramidale Mg(N_i)₄O moiety in [Mg(L)pc] and the solvates [Mg(L)pc] · S (S = CH₂Cl₂, thf, 2py) generally do not vary significantly: Mg–N_i/2.035(3) –2.061(3) Å, Mg–O/1.955(2)–2.000(3) Å. The Mg atom is displaced by ca. 0.52 Å out of the (N_i)₄ plane towards the O atom and the Mg–O–P moiety is bent (ca. 153°). [Zn(L)pc] · S crystallizes as a mixed crystal of equal parts of the conformer with a bent (155.1(3)°) and that of a quasi linear Zn–O–P moiety (174.2(3)°). Structural data of the Zn(N_i)₄O moiety: (Zn–N_i)_av: 2.024/2.013 Å; Zn–O: 2.050(4)/2.081(4) Å; Zn–(N_i)₄: 0.40/0.33 Å. In the crystal, the Mg and Zn derivates aggregate in double layers forming pairs. The pc ligands in the triclinic complexes with good overlap of the neighbouring pc ligands are in a waving conformation, while those in the monoclinic complexes with weak overlap are in a concave conformation.     

Zinkiodate – Schwingungsspektren (IR,Raman) und Kristallstruktur von Zn(IO3)2 · 2 H2O

Zinc Iodates – Infrared and Raman Spectra, Crystal Structure of Zn(IO₃)₂ · 2 H₂O The zinc iodates Zn(IO₃)₂ · 2 H₂O and Zn(IO₃)₂ as well as α‐Co(IO₃)₂ · 2 H₂O were studied by X‐ray, IR‐ and Raman spectroscopic methods. The crystal structure of the dihydrate, which is isostructural with the respective cobalt compound, was determined by X‐ray single‐crystal studies (space group P1, Z = 2, a = 490,60(4), b = 667,31(5), c = 1088,85(9) pm, α = 98,855(6), β = 91,119(7), and γ = 92,841(6)°, R1 = 2,55%, 2639 unique reflections I > 2σ(I)). Transconfigurated Zn(IO₃)₄(H₂O)₂ octahedra are threedimensionally connected via common IO₃^– ions parallel to [001] and hydrogen bonds parallel to [100] and [010], respectively. Anhydrous Zn(IO₃)₂ crystallizes in space group P2₁ (Z = 2) with a = 548,9(2), b = 512,4(1), c = 941,8(2) pm, and β = 90,5(3)°. The structure of Zn(IO₃)₂ is a monoclinically distorted variant of the structures of β‐Ni(IO₃)₂ (space group P6₃) and Co(IO₃)₂ (P3). The O–H … O–IO₂ hydrogen bonds of the crystallographically different H₂O molecules of the dihydrates (ν_OD (OD stretching modes of isotopically dilute samples) 2430, 2415, 2333 and 2300 cm^–1, Zn(IO₃)₂ · 2 H₂O, 90 K) are examples to the matter of fact that O … O distances are only a bad measure for the strength of hydrogen bonds. The infrared and Raman spectra as well as a group theoretical treatment are presented and discussed with respect to mutual exclusion principle (possible space groups), the strength of the hydrogen bonds and the distortion of the IO₃^– ions at the C₁ lattice sites.     

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.     

Die Kristallstruktur der hydratisierten Cyanokomplexe NMe4MnII[(Mn, Cr)III(CN)6] · 3 H2O und NMe4Cd[MIII(CN)6] · 3 H2O (MIII = Fe,Co): Verwandte des Berliner Blaus

The Crystal Structure of the Hydrated Cyano Complexes NMe₄Mn^II[(Mn, Cr)^III(CN)₆] · 3 H₂O and NMe₄Cd[M^III(CN)₆] · 3 H₂O (M^III = Fe, Co): Compounds Related to Prussian Blue The crystal structures of the isotypic tetragonal compounds (space group I4, Z = 10) NMe₄Mn^II · [(Mn, Cr)^III(CN)₆] · 3 H₂O (a = 1653.2(4), c = 1728.8(6) pm), NMe₄Cd[Fe(CN)₆] · 3 H₂O (a = 1642.7(1), c = 1733.1(1) pm) and NMe₄Cd[Co(CN)₆] · 3 H₂O (a = 1632.1(2), c = 1722.4(3) pm) were determined by X‐rays. They exhibit ⊥ c cyanobridged layers of octahedra [M^III(CN)₆] and [M^IIN₄(OH₂)₂], which punctually are interconnected also || c to yield altogether a spaceous framework. The M^II atoms at the positions linking into the third dimension are only five‐coordinated and form square pyramids [M^IIN₅] with angles N–M^II–N near 104° and distances of Mn–N: 1 × 214, 4 × 219 pm; Cd–N: 1 × 220 resp. 222, 4 × 226 resp. 228 pm. Further details and structural relations within the family of Prussian Blue are reported and discussed.     

Synthese und Struktur von Hydrogensulfaten des Typs M(HSO4)(H2SO4) (M = Rb,Cs und NH4)

Synthesis and Structure of Hydrogen Sulfates of the Type M(HSO₄)(H₂SO₄) (M = Rb, Cs and NH₄) From the binary systems M₂SO₄/H₂SO₄ (M = Rb, Cs, NH₄), three new hydrogen sulfates of the type M(HSO₄)(H₂SO₄) could be synthesized and structural characterized. The rubidium and caesium compounds are isotypic whereas NH₄(HSO₄)(H₂SO₄) is topologically very similar to both. All three compounds crystallize with nearly identical cell parameters [Rb: a = 7.382(1), b = 12.440(2), c = 7.861(2), β = 93.03(3); Cs: a = 7.604(1), b = 12.689(2), c = 8.092(2), β = 92.44(3); NH₄: a = 7.521(3), b = 12.541(5), c = 7.749(3), β = 92.74(3)], in the monoclinic space group P2₁/c, There exist two kinds of SO₄-tetrahedra: HSO₄^? anions (S1) and H₂SO₄-molecules (S2). The HSO₄^? anions form hydrogen bridged zigzag chains. In the case of the Rb and Cs compounds, the H₂SO₄ molecules connect these chains forming double layers. The metal atoms are coordinated by 9 O-atoms with M? O-distances of 2.97 – 3.39 Å (Rb) and 3.13 – 3.51 Å (Cs). In the ammonium compound additional hydrogen bonds are formed originating from the NH₄⁺ cation. This finally leads to the formation of S2? NH₄⁺ chains (parallel to the S1 chains) as well as to a three-dimensional connection of both kinds of chains.     

(NH4)4Cd(HSeIVO3)2(SeVIO4)2: a new structure type with kröhnkite‐like chains

Tetra­ammonium cadmium di­hydrogenselenite(IV) diselen­ate(VI), (NH₄)₄Cd(HSe^IVO₃)₂(Se^VIO₄)₂, is the third example of a compound containing both hydrogen selenite and selenate anions, and has a new structure type. It contains kröhnkite‐like heteropolyhedral chains in which CdO₆ octahedra are linked via bridging HSeO₃ groups, having their remaining two trans apices decorated by SeO₄ groups. The charge‐balancing NH₄ groups are involved in weak hydrogen bonding, whereas the H atom of the HSeO₃ group provides a strong hydrogen bond [O⋯O = 2.614 (5) Å]. The average Cd—O bond length is 2.298 Å. All atoms are on general positions except Cd (on ). Relations to the kröhnkite‐type compounds Na₂Mg(SO₃)·2H₂O, Ba₂CoCl₂(SeO₃)₂ and Ba₂Ca(HPO₄)₂(H₂PO₄)₂, and to the mineral curetonite are dis­cussed. Unit‐cell data are given for an isotypic Mn^II analogue.     

Synthese,Kristallstrukturen und thermisches Verhalten von Er2(SO4)3 · 8 H2O und Er2(SO4)3 · 4 H2O

Syntheses, Crystal Structures, and Thermal Behavior of Er₂(SO₄)₃ · 8 H₂O and Er₂(SO₄)₃ · 4 H₂O Evaporation of aqueous solutions of Er₂(SO₄)₃ yields light pink single crystals of Er₂(SO₄)₃ · 8 H₂O. X-ray single crystal investigations show that the compound crystallizes monoclinically (C2/c, Z = 8, a = 1346.1(3), b = 667.21(1), c = 1816.2(6) pm, β = 101.90(3)°, R_all = 0.0169) with eightfold coordination of Er³⁺, according to Er(SO₄)₄(H₂O)₄. DSC- and temperature dependent X-ray powder investigations show that the decomposition of the hydrate follows a two step mechanism, firstly yielding Er₂(SO₄)₃ · 3 H₂O and finally Er₂(SO₄)₃. Attempts to synthesize Er₂(SO₄)₃ · 3 H₂O led to another hydrate, Er₂(SO₄)₃ · 4 H₂O. There are two crystallographically different Er³⁺ ions in the triclinic structure (P 1, Z = 2, a = 663.5(2), b = 905.5(2), c = 1046.5(2) pm, α = 93.59(3)°, β = 107.18(2)°, γ = 99.12(3)°, R_all = 0.0248). Er(1)³⁺ is coordinated by five SO₄^2– groups and three H₂O molecules, Er(2)³⁺ is surrounded by six SO₄^2– groups and one H₂O molecule. The thermal decomposition of the tetrahydrate yields Er₂(SO₄)₃ in a one step process. In both cases the dehydration produces the anhydrous sulfate in a modification different from the one known so far.