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Halogen Ligand Exchange between Diboron(4) Molecules. Synthesis of B2I4 NMR-studies of mixtures of B2F4/B2Cl4 and B2Cl4/B2Br4 respectively show a high degree of ligand exchange in the latter a lower in the first system. An assignement to different mixed halide compounds was not possible. ? BI3 and B2Cl4 react to form B2I4 in almost quantitative yield; spectroscopic data of tetraiodo-diboran(4) are given. 相似文献
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Mixed Crystals from A4B3 Molecules (A = P, As; B = S, Se) The system P4S3? P4Se3? As4S3? As4Se3 was investigated by thermal and x-ray methods. Five regions of solid solubility with different crystal structures were found at room temperature. The range of existence can be influenced by the temperature of annealing. All these phases transform into a plastic-crystalline modification with complete solid solubility at higher temperature. A decomposition reaction of the A4B3 molecules was observed in the P4Se3/As4Se3/As4S3 part of the system. The molecules decompose into A4B4 molecules and an amorphous phase. The existence of all molecules of the type PnAs4–nSmSe3–m (n = 0–4, m = 0–3) and also As4SmSe4–m (m = 1–3) was verified by mass spectrometric measurements. The thermochemical data of the mixed crystals are determined by the type of the constituent A4B3 molecules. The temperature and the entropy of the α–β transition are lower for mixed crystals, formed by substituted molecules, than for those of the same structure, consisting of pure A4B3 molecules. 相似文献
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The distribution of activity of22Na+ and24Na+ in the heterogeneous equilibrium of a cationic exchange resin and the aqueous or methanolic solution was measured in order
to evaluate an isotope effect. Using Li+-charged ion exchanger in methanol, an enrichment of24Na was observed. If bicyclic aminopolyethers (221, 222) are present in the solution, this effect is not seen. This means that
the complexing agents above carry out an enrichment themselves, as could be shown by calculating the corresponding elementary
separation factor. The enrichment of24Na on the ion exchanger was measured directly by using Cs+-charged exchangers. The analytical method applied is described, and the limits of error are discussed.
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Ohne Zusammenfassung 相似文献
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Dr. Theodor N. Kleinert 《Monatshefte für Chemie / Chemical Monthly》1964,95(2):387-389
Zusammenfassung Bei der UV-Bestrahlung von Cellulose werden freie Radikale gebildet, deren Menge in einem annähernd linearen Verhältnis zur Kettenspaltung steht. Diese Bildung freier Radikale ist eine reine Wirkung der Lichtenergie und unabhängig davon, ob Sauerstoff anwesend ist oder nicht. Peroxydbildung in Anwesenheit von Sauerstoff wird auf eine Radikalkombination mit Sauerstoff zurückgeführt. Die beobachteten Änderungen verschiedener chemischer und optischer Eigenschaften bestrahlter Cellulosen werden als Reaktionen der gebildeten Radikale gedeutet.Mit 1 AbbildungDie vorliegenden Untersuchungen wurden zum Teil in der Abteilung für angewandte Chemie, National Research Council, Ottawa, zum Teil am Pulp and Paper Research Institute of Canada, Montreal, durchgeführt. Ein eingehender Bericht in englischer Sprache wird demnächst an anderer Stelle veröffentlicht werden. 相似文献