Die Kinetik der Murexid-Komplexbildung mit Kationen verschiedenen Koordinationscharakters

The kinetics of the reaction of murexide with different divalent metal ions of class A and B have been measured by the temperature-jump-relaxation method. The second-order formation rate constant increases in the sequence Ni²⁺ < Co²⁺ < Mn²⁺ < Zn²⁺ < Cd²⁺ ? Cu²⁺ ? Ca²⁺ < Sr²⁺ < Ba²⁺ < Pb²⁺. Thermodynamic data obtained from kinetic and equilibrium studies, respectively, are in good agreement. The results are compared with the characteristic rate constants for H₂O-exchange in the inner coordination sphere of these metal ions, which follow the same sequence. The rate constants of the reaction of murexide with various trivalent metal ions, including the lanthanides, are also discussed in terms of current ideas on metal complex formation.     

Bestimmung von Bor in Ferrobor mit der ICP-Spektrometrie

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Determination of boron in ferro-boron by ICP spectrometry

     

Systematischer Gang der qualitativen Analyse mit kleinen Mengen Kationen

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Ligandenaustauschreaktionen von Fluoratomen mit Chloratomen bei Phosphorverbindungen der Koordinationszahl 3 und 4

Ligand-exchange reactions of fluorine versus chlorine atoms in phosphorus compounds with coordination number 3 or 4 Fluorine versus chlorine ligand-exchange reactions were carried out on the following phosphorus-based central moieties: CH₃P <, CH₃P(O)<, CH₃P(S)< and CH₃P(Se)<. The measured equilibrium distributions were shown to favour the species which result from an accumulation of like substituents on the central moieties, whereas the equilibrium distribution of chlorine vs bromine on CH₃P(O) < was found to be almost random. These fluorine exchanging systems thus represent the unusual case of large positive deviation from random distribution. It is also noteworthy that the equilibrium distributions depend only very little on the nature of the atom which is bonded to phosphorus in the “isolated” position. System CH₃PF₂/CH₃PCl₂ could not be studied quantitatively owing to the competitive dismutation of CH₃PF₂; however, evidence is given for fast initial redistribution of the halogens on the methylphosphorus moiety and for the transient formation of CH₃PFCl.     

Rb2TiO3, ein neues Oxotitanat mit der Koordinationszahl 4

Rb₂TiO₃, a New Oxotitanate with Coordination Number 4 Rb₂TiO₃ cristallizes according to single crystal datas [544 Okl? 4kl, Mo? Kα] orthorhombic, a = 6.01₅, b = 11.93₆, c = 13.36₆ Å, Z = 8, space group D? Cmca, d_rö = 3.69, d_pyk = 3.65 g cm^?3; for occupied positions and atomic parameters see text. Surprisingly the coordination number of Ti to 0 turns out to be 4. The chains [TiO_1/1O_1/1O_2/2] are placed along [100]. The Madelung part of lattice energy (MAPLE) of Rb₂TiO₃ is calculated and discussed. In order to display the characteristics of the structure, further MAPLE-calculations have been carried out. K₂TiO₃ belongs to the Cs₂PbO₃-Family of structure with C.N. 5 of Ti to 0. Cs₂TiO₃ and Rb₂TiO₃ are not isotypic.     

Extraktionsversuche mit den Diphenylcarbazonkomplexen verschiedener Kationen

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Bei der Bestimmung von Bor in elementarem Bor

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Wasserfreies Octamolybdat mit Trimethylhexadecylammonium‐Kationen

Anhydrous Octamolybdate with Trimethyl Hexadecyl Ammonium Cations The compound [N(CH₃)₃C₁₆H₃₃]₄Mo₈O₂₆ was synthesized via a template route in form of plate‐like crystals which have been characterized by Xray analysis (P1 (Nr. 2); a = 1003.0(4) pm, b = 1123.6(4) pm, c = 2528(1) pm, α = 97.42(3)°, β = 96.09(3)°, γ = 115.76(3)°; Z = 1). [N(CH₃)₃C₁₆H₃₃]₄Mo₈O₂₆ is a crystalline composite of octamolybdate anions and trimethyl hexadecyl ammonium cations. Cations and anions organize in separate spatial sections forming layers of inorganic and organic species. Another composite of the same constituents has been found which is an amorphous lamellar material consisting of alternating layers of MoO₃ and templates.