29Si-NMR-Spektroskopie an Silicatlösungen. II. Zur Abhängigkeit der Struktur der Silicatanionen in wäßrigen Natriumsilicatlösungen vom Na : Si-Verhältnis

²⁹Si-NMR Spectroscopy of Silicate Solutions. II. On the Dependence of the Structure of Silicate Anions in Water Solutions from the Na : Si Ratio The ²⁹Si-FT-NMR spectra of 13 sodiumsilicate solutions with different Na:Si ratios are investigated with regard to the structure of the silicate anions in the solutions. The 5 typical building units (Monosilicate, end-, middle-, branching and crosslinking groups) show characteristic and non overlapping ranges of the ²⁹Si chemical shift with many signals splittings caused by different neighbouring group effects. The relative intensities of the signals give informations on the concentrations and the equilibrium of condensation of the silicate anions in dependence of the Na:Si ratio. It is shown, that many types of anions with different degree of condensation coexist in an equilibrium, which is shiftet to the polymer silicate anions with high content of branching and crosslinking groups on the decrease of the Na:Si ratio.     

Untersuchungen zum Einfluß der 1-Hydroxyethan-1,1-diphosphonsäure,HEDP, auf die Kristallisation von CaCO3 in Ca(HCO3)2-Lösungen

Studies about the Influence of 1-Hydroxyethane-1,1-diphosphonic Acid, HEDP, on the Crystallization of CaCO₃ in Ca(HCO₃)₂ Solutions When cleaned air at 40 °C is passed through solutions of Ca(HCO₃)₂ (4) mmol/l containing ≥5 μmol HEDP/1 x-ray-pure Vaterite crystallizes after a longer time. The reason of the delayed crystallization is not — as usual said in literature — a disturbed growth of the seed crystals of Calcite and Aragonite, but the changed conditions of the formation of crystal nuclei. This is demonstrated by measuring the scattered light, the pH-value and ionic balances. The most important factors of the stability of Ca(HCO₃)₂-solutions containing HEDP are characterized.     

Beiträge zur Chemie des Phosphors. 61. Zur Struktur der Salze M(PC6H5)3, [M = K,Na]

Contributions to the Chemistry of Phosphorus. 61 About the Structure of the Salts M (PC₆H₅)₃ (M = K, Na) The structure of the salts M(PC₆H₅)₃ (M = K, Na) was determined by means of ²¹P nmr spectroscopy. Contrary to the opinion presented in the literature on the potassium salt, both compounds have an open chain structure. so that they are 1,3-Dialkali-l,2,3-triphenyl-tri-phosphides. The structure was proved by comparison of the ³¹P nnmr parameters with those of triphenyl-cyclotriphosphane 3 . and 1,2,3 triphenyl-triphosphane 5 . The occurrence of only AB₂ spin systems each for both of the pure salts as well as for an equimolecular mixture of these compounds indicates a fast inter- and possibly intramolecular metal exchange in solution. The latter of which probably takes place in the case of the solved homologue 1,-4-dipotassium-l,2,3,4-tetra-phenyl-tetraphosphide 6. for which the ³¹P nmr data indicate a quasi-cyclic conformation.     

Darstellung der Koordinatenräume der Gleichgewichtslösungen der Ein-Bodensalz-Gebiete des Systems H2O/Na2/K2/Mg/SO4/Cl2 bei 25°C durch Schalen,die sich durch Höhenlinien der „Basisfläche”︁ der Räume ergeben

Coordinate Spaces of the Equilibrium Solutions of one-sediment Regions in the System H₂O/Na₂/K₂/Mg/SO₄/Cl₂ at 25°C by Shells, which are represented by Niveau lines of “basal Areas” The coordinate spaces of 15 regions of the above mentioned system are constructed by one-dimensional arraying of their limiting areas. The two groups of lower and upper limiting areas merge within the so constructed “basal area”. For spacial representation, the two groups are assigned by niveau lines, thus leading to shells, which circumscribe the coordinate spaces. For evaluating these shell diagrams, the niveaus are substituted by nomographic scales allowing the incorporation of further “supplemental coordinates”. Practical applications of the shell diagrams are communicated.     

Zur Kinetik des Abbaus von Polykieselsäure (H2SiO3)x in wäßriger Lösung

The degradation of polysilicic acid has been investigated in the region of pH = 1.3–5.5 and 0–65°C. At pH = 3.3 there was found a maximum (18.5 kcal/mol) and at pH = 4.3 a minimum (15.6 kcal/mol) of the activation of this reaction. Nucleophiles and HF accelerate the degradation.     

AlCl3 · 2NH3 – eine Verbindung mit der Kristallstruktur eines Tetraammindichloroaluminium-tetrachloroaluminats – [AlCl2(NH3)4]+[AlCl4]−

ACl₃ · 2NH₃ – a Compound with the Crystal Structure of a Tetraammine Dichloroaluminiumtetrachloroaluminate – [AlCl₂(NH₃)₄]⁺[AlCl₄]^? Ammoniates of aluminiumchloride AlCl₃ · xNH₃ are in discussion as starting materials for the synthesis of aluminiumnitride. Therefore the reactions of melts of monoamminealuminiumchloride with ammonia were investigated. They react at 150°C within 10 min with one mole of ammonia to the diammoniate, [AlCl₂(NH₃)₄]⁺[AlCl₄]^?. The pure compound can be obtained by sublimation at 200°C in vacuumline apparatus. X-ray structure determination on [AlCl₂(NH₃)₄]⁺[AlCl₄]^? was carried out: see “Inhaltsübersicht”.     

Zur Kenntnis der Substitutionsprodukte der (2H)-Imidazol-4(3H)-thione und 2H-Imidazol-4(3H)-one

2H-Imidazole-4(3H)-thiones (a), available from methyl alkyl and methyl aryl ketones with sulfur and ammonia, react via their corresponding N-sodium compounds or in presence of tert. amines with alkyl and aryl carboxylic acid chlorides to give the corresponding intensely coloured (orange to violett) cryst. 3-acyl-2H-imidazole-4(3H)-thiones4 a-q and6–26. With dicarboxylic acid dichlorides the colourless cryst. N,N′-diacyl-bis-3-imidazoline-5-thiones5 a-d and27–32 are obtained. With carbamic acid chlorides and chloroformic acid esters the corresponding urea (33–35) and urethane derivatives36, 37 are formed. In an analogous way 2H-imidazol-4(3H)-ones react with acid chlorides to 3-acyl-2-imidazol-4(3H)-ones (44–50), which can also be obtained by treating the corresponding 3-acyl-2H-imidazole-4(3H)-thione with KMnO₄.     

Beiträge zur Chemie des Phosphors. 168 [1]. Zur Kenntnis der Isomere von Tetraphosphan(6), P4H6

Contributions to the Chemistry of Phosphorus. 168. About the Isomers of Tetraphosphane(6), P₄H₆ Additional informations about the ³¹P-NMR parameters of d,l- and meso-n-P₄H₆ as well as of iso-P₄H₆ have been obtained by ³¹P-NMR spectroscopic investigations of mixtures of phosphanes containing 26—48 P-% of tetraphosphane(6). On the basis of the differences in the ³J(PP)-coupling constants the observed AA′BB′-spin systems have been reassigned to the various diastereomers of n-P₄H₆.     

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.     

Beiträge zur Chemie des Phosphors. 67. Zur Kenntnis der Cyclotriphosphane (PC6H5)3, (PC6H5)2(PC2H5) und (PC6H5)2(PCH3)

Contributions to the Chemistry of Phosphorus. 67. About the Cyclotriphosphanes (PC₆H₅)₃, (PC₆H₅)₂(PC₂H₅), and (PC₆H₅)₂(PCH₃) The reaction of (CH₃)₃Si(C₆H₅)P? P(C₆H₅)Si(CH₃)₃ with RPCl₂ (R = C₆H₅, C₂H₅, CH₃) yields the cyclotriphosphanes (PC₆H₅)₃ 1 , (PC₆H₅)₂(PC₂H₅) 3 , and (PC₆H₅)₂(PCH₃) 4 , respectively. Besides, the corresponding homo- and mixed-substituted cyclotetraphosphanes, cyclopentaphosphanes, and cyclohexaphosphanes are formed. The relative concentrations of the cyclotriphosphanes in the reaction mixtures decrease continuously, whereas those of the cyclopentaphosphanes increase. The reasons for these ring-interconversion reactions of the cyclophosphanes (PR)_n are discussed. The cyclotriphosphanes 1, 3 , and 4 are characterized by ³¹P chemical shifts between +130 and +160 ppm that are at considerable high field compared to open-chain triphosphanes and cyclophosphanes of different ring-size. The substituents R are situated on both sides of the P₃-ring plane, thus giving rise to two diastereomers of 3 that are observed simultaneously in the statistically expected ratio. The ³¹P n.m.r. parameters of 1 and 3 are reported and discussed.     

Zur Synthese und Kristallstruktur der ternären Carbide Na2PdC2 und Na2PtC2

Syntheses and Crystal Structures of Ternary Carbides Na₂PdC₂ and Na₂PtC₂ Na₂PdC₂ and Na₂PtC₂ were synthesized by the reaction of sodium carbide with palladium and platinum respectively. The crystal structures could be solved from X-ray powder diffraction data (space group: P3 m1, Z = 1). Both compounds crystallize in a new structure type with [M(C₂)_2/2^2?] chains (M?Pd, Pt) as the characteristic structural unit. The existence of a C? C triple bond was confirmed by Raman spectroscopy.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 47. Zur Reaktion von Hexachloroceraten(IV) mit Lithiumorganylen

Contributions to the Chemistry of Organo-Transition Metal Compounds. 47. Reactions of Hexachlorocerates(IV) with Organolithium Compounds Pyridinium hexachlorocerate(IV) reacts with lithium organyls RLi RLi (R = 1-Nor, (CH₃)₂NCH₂CH₂CH₂, n-C₄H₉) in the molar ratio 1:2 with formation of Li₂[CeCl₆] · 2 NC₅H₅. A further mol RLi effects a reduction to Li₃[CeCl₆] · 2 NC₅H₅. With an excess of RLi amidocerium(III) complexes of the typ Li₄ are formed. Li₂[CeCl₆] is formed also at reactions of quartery ammonium salts, e. g. [C₆H₅CH₂N(C₂H₅)₃]₂[CeCl₆], with RLi (R = 1-Nor, Me₂₂NCH₂CH₂CH₂) followed by an reduction to Li₃[CeCl₆]. An excess of the lithium organyl effects the formation Li₄[RCeCl₆] complexes. The yielded compounds were characterized by elementary analysis, the hydrolysis and deuterolysis products, magnetic moments, and IR-spectra.     

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.     

AlCl3 · 3NH3 — eine Verbindung mit der Kristallstruktur eines Tetraammindichloroaluminium-diammintetrachloroaluminats: [AlCl2(NH3)4]+[AlCl4(NH3)2]−

AlCl₃ · 3NH₃ — a Compound with the Crystal Structure of a Tetraammine Dichloro Aluminium-Diammine Tetrachloro Aluminate: [AlCl₂(NH₃)₄]⁺[AlCl₄(NH₃)₂]^? . AlCl₃ · 3 NH₃ ? [AlCl₂(NH₃)₄]⁺ [AlCl₄(NH₃)₂]^? forms during the reaction of two mole NH₃ with AlCl₃(NH₃) at T ≥ 200°C. Repeated heating and cooling within 48 h between 200°C and 250°C gives a homogeneous product with total uptake of the necessary amount of NH₃. Slow sublimation in a vacuum line apparatus at 200°C gives crystals of the triammoniate sufficient for a X-ray structure determination: The compound contains elongated [AlCl₂(NH₃)₄]⁺ octahedra and compressed [AlCl₄(NH₃)₂]^? octahedra. Besides ionic bonding hydrogen bridge bonds with 3.369 Å ? d(N—H … Cl) ? 3.589 Å stabilize the atomic arrangement.