Über basische Aluminiumsalze und ihre Lösungen. XVI. Kinetische Untersuchungen an niederbasischen Aluminiumchloridlösungen

Basic Aluminum Salts and their Solutions. XVI. Kinetic Studies on Low Basic Aluminum Chloride Solutions Basic aluminum chloride solutions of low basicity were prepared by different methods and investigated by means of the ferrone kinetics. In solutions prepared by expulsion of hydrogen chloride or addition of solid sodium carbonate preferably dimeric cations are formed. In solutions prepared by addition of sodium hydroxide solution or sodium carbonate solution only at very low basicity small quantities of dimeric ions are formed, at increasing basicity tridecameric ions arise. An explanation of this behaviour is given, involving the action of hydroxide ions and a possible formation of the dihydroxy-aluminum complex. The rate constant for the reaction of the dimeric ions with the ferrone reagent was determined to be k = 0.97 ± 0.06 min^?1.     

Über basische Aluminiumsalze und ihre Lösungen. (XII). Vergleichende Untersuchungen an unterschiedlich dargestellten Basischen Aluminiumchloridlösungen

Basic Aluminium Salts and their Solutions. XII. Comparative Studies of Basic Aluminium Chloride Solutions Prepared in Different Ways Basic aluminum chloride solutions were prepared from solutions of the neutral salt by adding alkali or by dissolution of metallic aluminum. The solutions prepared by both methods contain monomeric, tridecameric, and polymeric aluminum cations, as was shown by the ferrone method and by ²⁷Al NMR spectroscopy. The formation of tridecameric ions is favoured by low temperature, low basicity, and in diluted solution; at higher temperatures and basicities they are transformed to polymeric and monomeric forms.     

Über basische Aluminiumsalze und ihre Lösungen. VII. Zum Einfluß der Herstellungsbedingungen,der Konzentration und der Alterungszeit auf die Zusammensetzung von Lösungen basischer Aluminiumsalze

Basic Aluminium Salts and their Solutions. VII. Influence of Preparation, Concentration, and Aging on the Constitution of Solutions of Basic Aluminium Salts 0.1 to 4 molar basic aluminium chloride solutions – prepared by dissolving aluminium metal in substoichiometric quantities of hydrochloric acid and 10^?4 to 0.2 molar basic solutions of aluminium chloride and perchlorate – prepared by adding alkali to the solutions of the neutral salts were investigated for the kinetics of their reactions with ferrone and by ²⁷Al NMR spectroscopy. In all solutions the contents of polymeric species decreases at equal basicity with increasing aluminium concentration. On the other hand the Al₁₃O₄₀ complex is only formed in solutions prepared by addition of alkali. The differences of composition are confirmed by the aging behaviour of the solutions.     

Über basische Aluminiumsalze und ihre Lösungen. X. NMR-Untersuchungen am tridekameren Al-oxo-hydroxo-Kation

Basic Aluminum Salts and their Solutions. X. NMR-Investigations on the Tridecameric Al-Oxo-Hydroxo Cation Using solid-state high resolution ²⁷Al-NMR it is shown that in the basic aluminum chloride with a degree of alkalinity r = OH/Al = 2.5 cations of the [Al₁₃O₄(OH)₂₅(H₂O)₁₁]⁶⁺ type exist. The ¹H-NMR detects besides the constitutional water still an amount of mobile, enclosed H₂O molecules which can be removed by thermal treatment at 104°C. The ²⁷Al spectrum of the aqueous solutions of the chloride shows only one peak at 62.5 ppm which is characteristic for the tridecameric cation. Adding HCl to the solution causes a decomposition to low-molecular species (peak at 0 ppm). Adding NaOH to the aqueous solution of the chloride effects a rearrangement of the tridecameric cations to higher molecular particles which are no more accessible by ²⁷Al-NMR.     

Über basische Aluminiumsalze und ihre Lösungen. XIV. Zur Strukturellen Funktion des Wassers in basischen Aluminiumchloriden

Basic Aluminum Salts and their Solutions. XIV. Structural Function of Water in Basic Aluminum Chlorides The structural function of water in basic aluminum chlorides as intercalation compounds was examined by X-ray, thermoanalytical, and solid state ¹H-NMR investigations in connection with charging experiments in water vapor atmosphere. The basic salts were prepared by hydrothermal reaction of χ-Al₂O₃ with hydrochloric acid. It was shown, that the structural changes caused by loading with water vapor are reversible; the original state of the compounds may be recovered by a treatment in vacuum or by heating up to 130°C. The ¹H-NMR spectrum of the H₂O-loaded compounds consists of three components, caused by protons (a) of fixed coordination water or of OH^? ions, (b) of adsorbed water molecules with possibility of random motion, (c) of water molecules with hindered mobility. The development of spectra as a function of specimen temperature and of specimen treatment shows, that the third component is bound to intercalated water, located in voids, the dimensions of which are in the order of magnitude of water molecules.     

Über basische Aluminiumsalze und ihre Lösungen. (XIII). Kristalline basische Aluminiumchloride als Produkte der Rehydratisierung und Hydrochlorierung von Übergangstonerden

Basic Aluminum Salts and their Solutions. XIII. Crystalline Basic Aluminum Chlorides Formed as Products of Rehydration and Hydrochlorination of Transition Aluminas By reaction of transition aluminas with hydrochloric acid in sealed tubes at temperatures above 100°C crystalline basic aluminum chlorides were prepared. From the aluminum oxides used (χ-Al₂O₃, χ-Al₂O₃, and χ-Al₂O₃) χ-Al₂O₃ was most suitable for preparation. The homogeneous basic salts are characterized by a certain variability in composition as phases. After a treatment with water vapor there is a remarkable change in the X-ray diagrams of the compounds. It is shown, that at this alteration the lattice was only changed unessentially. Therefore the existence of intercalation compounds with a 3D host lattice is assumed; the water molecules are located at defined positions in the voids.     

Über basische Aluminiumsalze und ihre Lösungen. XI. Vergleichende 27Al-NMR-Untersuchungen am Mineral Zunyit und basischen Aluminium-Salzen mit tridekameren Al-oxo-hydroxo-aquo-Kationen

Basic Aluminium Salts and their Solutions. XI. ²⁷Al-NMR Studies Comparing the Mineral Zunyite and Basic Aluminium Salts of Tridecameric Al-oxo-hydroxo-aquo-Cations Solid-state high resolution ²⁷Al NMR studies of basic aluminum sulphate and the mineral zunyite, both containing tridecameric Al-oxo-hydroxo groups, show different ²⁷Al spectra. While for zunyite both AlO₆ octahedra (0 ppm) and the central AlO₄ tetrahedron (69 ppm) are observed in the spectrum, in the case of the basic aluminum sulphate only the tetrahedrally coordinated Al (59 ppm) is detected by NMR. This behaviour is explained by structural data, which indicate stronger distortions of the AlO₆ octahedra in the case of the basic aluminum sulphate. The increased shielding of the fourcoordinated Al of the basic sulphate is attributed to an increased ionic character of the Al? O bond in this compound.     

Über basische Aluminiumsalze und ihre Lösungen. VI. Darstellung und Charakterisierung eines wasserlöslichen Al13O40-Chlorides

Basic Aluminium Salts and their Solutions. VI. Preparation and Characterization of a Water-soluble Al₁₃O₄₀ Chloride The water-soluble chloride is prepared from the sparingly soluble basic aluminium sulfate [Al₁₃O₄(OH)₂₅(H₂O)₁₁](SO₄)₃ · xH₂O by reaction with barium chloride. From kinetic and ²⁷Al NMR measurements is concluded, that the solid chloride as well as its aqueous solution contain exclusively the Al₁₃O₄₀ cation. It is shown by differential thermal analysis that the solid chloride includes water in different linkage.     

Über die Silicatanionenkonstitution in Tetraethylammoniumsilicaten und ihren wäßrigen Lösungen

On the Constitution of Silicate Anions in Tetraethylammonium Silicates and their Aqueous Solutions Investigations by paperchromatography, ²⁹Si-NMR spectroscopy and trimethylsilylation method show that concentrated solutions of tetraethylammonium (TEA) silicates with molar TEA:Si ratios from 2.8 to 1 contain mainly double three-ring silicate anions. Besides of these small amount of mono-, di-, tri-, tetra-, cyclotri-, cyclotetra-, double four-ring- and other polycyclic silicate anions are present. From these solutions a crystalline double three-ring silicate of the formula [N(C₂H₅)₄]₆[Si₆O₁₅] · 57 H₂O could be obtained by crystallization at low temperature. Concentrated solutions with TEA:Si ratios of 0.8 to 0.6 contain mainly double three-, double four-, double five- an probably double six-ring silicate anions. From such solutions always the solid TEA-double four-ring silicate is obtained by crystallization. The reasons for the prefered formation of double ring silicate anions in TEA-silicate solutions and their crystallization are discussed.     

Über die Hydrolyse von Eisen(III)Salzlösungen. I. Die Hydrolyse der Lösungen von Eisen(III)chlorid

When a very diluted iron(III)chloride solution is slowly alkalified by a weak base, the deprotonation of [Fe(H₂O)₆]³⁺ proceeds in a first stage to form mono- and dinuclear hydroxoaquo-complexes. In a second stage 4 dimers condense around a chloride ion to form an eight membered ring, an embryon, which grows fast to very small crystals of the composition Fe₄O₃(OH)₅Cl and the structure of the β-FeOOH. These crystalline micells remain colloidally dissolved. If the pH is raised above approximately 3.4 the Cl^?- are exchanged against OH^?-ions and flocculation occurs. This shows that Pauli, assuming the micells of such sols to be polynuclear complex ions, is basically correct, and it follows that micells can also be micro-crystals. When an iron(III)chloride solution is neutralized fast with a strong base, an ‘amorphous’ precipitation is obtained which gives with MoK_α-X-rays only two broad reflections, showing that the iron oxide hydroxide octahedra are condensed in a highly disordered way. The coherently scattering areas of this precipitate are probably tetramers. Small amounts of primarily formed amorphous iron(III)hydroxide are transformed into β-FeOOH.     

Über den Einfluß von Temperatur und Fremdionen auf Eigenschaften und Bau der Natriumwasserglaslösungen

The Influence of Temperature and Impurities Addition on the Properties and the Constitution of Sodium Water Glass Solutions Sodium water glass (NaWG-)solutions of constant composition (SiO₂/Na₂O = 3,3; C_SiO2 = 6,2 M) and different concentration of impurities (Fe, Al, Ti, Cu, chloride, sulfate) were investigated in dependence on temperature by means of the dye absorption method, ¹H- and ²³Na-NMR spectroscopy. It is shown, that the differences in the dye absorption spectra of normalized technical NaWG-solutions, mainly depend on the Fe-concentration in the solutions and their thermal history. From the results follow a crosslinking of polymeric silicate species by Fe? O? Si bonds and/or hydrogen bridges and a fully or partially degradation of these bonds at higher temperatures (150°C).     

Über Glasbildung und Eigenschaften von Chalkogenidsystemen. XIX. Zur Glasbildung von HgSe mit Germaniumseleniden

Glass Formation and Properties of Chalcogenide Systems. XIX. Glass Formation of HgSe with Germanium Selenides Glass formation is found in the System HgSe? GeSe? GeSe₂ in a large range of composition. The dependence of properties such as glass transition temperature, mole volume, mole polarization, and electrical conductivity on composition suggests a remarkably lower modifier function of HgSe on the germanium selenide glasses in comparison to PbSe. Two regions which are characterized by different structural units in the glass can be deduced from the curves. Annealing results in the formation of the new compound Hg₂ GeSe₃ as well as of two phases which could not be identified up to now. In special limits of composition HgSe/GeSe melts form glasses, too.     

Über den Anionenaufbau wäßriger Tetra-n-propyl- und Tetraethylammoniumsilicatlösungen

On the Anion Constitutions of Aqueous Tetra-n-propylammonium and Tetraethylammonnium Silicate Solutions The constitution of the silicate anions present in 0.1 M to 3 M tetrapropylammonium-(TPA-) and tetraethylammonium-(TEA-)silicate solutions with molar TPA/Si ratios of 3, 1 and 0.6 and TEA/Si ratios of 3 and 1 is investigated by means of trimethylsilylation. Up to 16 different oligomeric silicate anions are detected and estimated quantitively. Type and quantitative dis-tribution of the silicate anions are very similar in diluted 0.1 M TEA- and TPA-silicate solutions. Concentrated TEA-silicate solutions contain preferably Si₆O₁₅^6? anions whereas concentrated TPA-silicate solutions are characterized by a broad distribution of different oligomeric silicate anions. The anion distribution of TPA- and TEA -silicate solutions is compared with the results of tetramethyl- and tetrabutylammonium silicate solutions studied previously.     

Über Oxocobaltate der Alkalimetalle. Zur Kenntnis von Li8CoO6

Oxocobaltates of Alkali Metals. On Li₈CoO₆. Hitherto unknown Li₈CoO₆, rubin- red single crystals, cristallizes according to WEISSENBERG and precession photographs (MoK_α) hexagonal with a = 5.44 Å, c = 10.87 Å; c/a = 2.0; Z = 2, space group C? P6₃cm. Atomic parameters see text. The structure derives from a closest packing of O^2?, ABACA … (The tetrahedral, ?isolated”? groups [CoO₄] show remarkable short distances Co–O (1.66 Å), comparable with [CoO₄] in Li₄CoO₄, being isotypic with Li₄SiO₄. The MADELUNG Part of Lattice Energy is calculated and discussed.