Polyol-Metall-Komplexe. X. Blei(II)-meso-oxolan-3,4-diolat(2−)-Monohydrat – ein polymeres Blei-alkoxid aus wäßriger Lösung

Polyol Metal Complexes. X. Lead(II) meso-Oxolane-3,4-diolate(2?) Monohydrate – a Polymeric Lead Alkoxide from Aqueous Solution In the colourless crystals of Pb(C₄H₆O₃) · H₂O (P2₁/c, a = 569.8(3), b = 607.6(4), c = 1856.9(9) pm, β = 89.90(4)°, V = 642.9(6) · 10⁶ pm³, Z = 4), lead(II)- and meso-oxolane-3,4-diolate(2?) ions form a one-dimensional coordination polymer; Pb^II is coordinated with four bridging alkoxide O-atoms (mean distance: 234.5 pm); some 100 pm more distant two μ-O-atoms of water molecules coordinate the lead ion.     

Selenostannate aus wäßriger Lösung: Darstellung und Struktur von Na4SnSe4 · 16 H2O

Selenostannates from Aqueous Solutions: Preparation and Structure of Na₄SnSe₄ · 16 H₂0 Pure selenostannates(IV) are prepared from aqueous solutions by reaction of SnSe₂, with alkali selenides, strictly excluding oxygen. Na₄SnSe₄ · 16 H₂O, being obtained from stoicheo-metric 1:2 quantities, is characterized by a complete X-ray structure analysis and by vibrational spectra. The compound is monoclinic (P2₁/m) with a = 8.673(3), b = 16.563(4), c = 8.647(2) Å, β = 92.10(2)°, Z = 2; it contains isolated tetrahedral SnSe₄^4? ions [Sn? Se 2.504(2)?2.527(2) Å, Se? Sn? Se 106.6(1)?111.1(1)°] which are in contact to the hydrated octahedral [Na(OH₂)₆]⁺ ions through Se…?H? O bridges within an extensive hydrogen bridge system. The stretching vibrations of the SnSe₄^4? ion are observed at 195 (n?₁) and 252 cm^?1 (n?₃). The stretching force constant is approximately 1.59 mdyn/Å.     

Selenostannate aus wäßriger Lösung Darstellung und Struktur von Na4Sn2Se6 · 13 H2O

Selenostannates from Aqueous Solution, Preparation and Structure of Na₄Sn₂Se₆ · 13 H₂O The dimeric anion Sn₂Se₆^4? is prepared by reaction of SnSe₂ with alkali metal selenide in a 1:1 molar ratio. The orange-red hydrated sodium salt Na₄Sn₂Se₆ · 13 H₂O is characterized by a complete X-ray structure analysis and by its vibrational spectrum. The compound is triclinic (P1 ) with a = 7.106(2), b = 10.330(2), c = 19.009(4) Å, α = 78.60(2), β = 85.66(2), γ = 72.85(2)° (?130°C), Z = 2. It contains isolated Sn₂Se₆^4? anions consisting of two edge-sharing tetrahedra [Sn? Se 2.456(1)–2.589(1) Å] which are in contact to the hydrated Na⁺ ions within an extensive hydrogen bridge system. Raman-active vibrations are observed at 260, 202, 188, 116, 93, and 78 cm^?1.     

Selenogermanate aus wäßriger Lösung: Darstellung und Struktur von Na4Ge2Se6 · 16 H2O

Selenogermanates from Aqueous Solution: Preparation and Structure of Na₄Ge₂Se₆ · 16 H₂O Selenogermanates(IV) are prepared from aqueous solutions by reaction of alkali selenides with GeSe₂. Na₄Ge₂Se₆ · 16 H₂O, being obtained from stoichiometric 1:1 quantities, is characterized by a complete X-ray structure analysis and by vibrational spectra. The compound is monoclinic (P2₁/c) with a = 9.894(4), b = 11.781(5), c = 12.225(6) Å, β = 92.90(4)°, Z = 2. It contains isolated Ge₂Se₆^4? anions consisting of two edge-sharing tetrahedra [Ge? Se 2.303(2)–2.419(2) Å] which are in contact to the hydrated octahedral [Na(H₂O)₆]⁺ ions through Se ? H? O bridges within an extensive hydrogen bridge system. Raman-active vibrations are observed at 306, 294, 207, 139, and 121 cm^?1. Adamantane-like Ge₄Se₁₀^4? can be prepared in a similar way as Ge₂Se₆^4? if a 1:2 molar ratio of alkali selenide to GeSe₂ is employed.     

Vergleichende Betrachtung zur Kristallwachstumskinetik von CuSO4 · 5 H2O aus wäßriger Lösung

Comparison of the Crystal Growth Rate Constants of CuSO₄ · 5 H₂O from Different Experimental Methods The growth rate of CuSO₄ · 5 H₂O was investigated using different experimental methods. These are the method of the fixed single crystal, fluidized bed experiments and the quasiisothermal batch technique. The overall growth rate constants are calculated from the different growth rate constants using the individual shape factors of volume and surface area. The kinetic coefficients well agree in respect to the difference of the experimental methods used.