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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 22 (1969), S. 73-82 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The grades of ordering as represented by I.R. and X-ray spectra for platy kaolinite, fire clay mineral, ball clay, dickite, nacrite and tubular dehydrated halloysite samples of various origin, are related. Well ordered kaolinite, has four bands 3,693, 3,668, 3,652 and 3,620 cm−1. In less ordered kaolinite, fire clay mineral and ball clay these bands have shifted a little or of the middle two, which are the weakest, only one band may be left (between brackets): less ordered kaolinite: 3,695, 3,667, 3,652 (3,653) and 3,620 cm−1; fire clay mineral 3,696, 3,668, 3,653 (3,653) and 3,621 cm−1; ball clay 3,697, 3,652 and 3,621 cm−1. Dehydrated halloysite has 3,693–3,698, 3,668, 3,650–3,654 and 3,620–3,626 cm−1 bands. In the most disordered dehydrated halloysite samples (Martinsberg and Baia Mare) only two bands are left at 3,696 and 3,624 cm−1. Dickite has four bands: 3,708, 3,656, 3,627 and 3,622 cm−1. For the lesser ordered Mexico sample it is 3,701, 3,652, 3,627 and 3,621 cm−1. Nacrite also has four bands i.e.: 3,700, 3,650, 3,627 and 3,620 cm−1. There is, apart from orientation effects, a wide variation in the absolute and especially in the relative intensities of the I.R. bands and X-ray reflections for each of the mineral groups investigated here, but of various origin. The need of a nomenclature adapted to the level of our knowledge about this matter to day and comprising all these variations included those in morphology is emphasized. Quantitative analyses, the adjective meant in the sense of an accuracy of minimal 5%, constitute a difficult problem which is perhaps even wholly impossible to solve with the conventional methods of today.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 243 (1968), S. 80-92 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird gezeigt, daß von den gebräuchlichen Methoden zur Aufnahme der Infrarotspektren von Mikromengen (Mikro-Flüssigkeitsküvette, Mikroreflexion, FMIR-Technik, Mikro-KBr-Preßtechnik) die Mikro-KBrPreßtechnik die weitaus empfindlichste ist. 0,1 μg Phenacetin können noch an Hand des Infrarotspektrums identifiziert werden. Die oft schwierige Präparation sehr kleiner Substanzmengen wird stark erleichtert, wenn die Substanz mittels eines porösen KBr-Keils aus dem Trägermaterial eluiert wird. Die abgebrochene Spitze, in der sich die Substanz danach befindet, kann direkt zu einem Mikro-KBr-Preßling gepreßt werden. Mit dieser Methode wurden die Infrarotspektren der Komponenten eines dünnschicht-chromatographisch getrennten Gemisches aufgenommen, das je 15 μg DDT, Methoxychlor und Methylparathion enthielt.
    Notes: Abstract It is shown that, among the methods currently used for scanning infrared spectra of micro-amounts (micro-liquid-cell, micro-reflectance, FMIR technique, micro-KBr-technique), the method using micro-KBr discs is by far the most sensitive one. It is possible to identify an amount as low as 0.1 μg of phenacetin by means of its infrared spectrum. The often difficult preparation of very small substance amounts is much facilitated when the substance is eluted from the support with the aid of a porous KBr wedge. The upper tip of the wedge, where the substance has concentrated, can then be broken off and shaped directly into a micro-KBr disc. This method was used for recording the infrared spectra of the components of a mixture separated previously by thin layer-chromatography and containing 15 μg each of DDT, Methoxychlor, and Methylparathion.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 369 (1969), S. 238-248 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: IR-spectra of LiCH3, Be(CH3)2, Mg(CH3)2, Li2CH2 and MgCH2 were taken and assigned. Proton magnetic resonance spectra of LiCH3, Be(CH3)2 are reported. The interpretation of both types of spectra leads to the coclusion, that with decreasing electronegativity the metal-methyl bond becomes more polar. Correspondingly, the C—H bond acquires increasing p character, which is dominating in the methylene compounds.
    Notes: Es wurden die IR-Spektren von LiCH3, Be(CH3)2, Li2CH2 und MgCH2 aufgenommen und zugeordnet. Weiterhin werden die Protonen-Resonanz-Spektren von LiCH3, Be(CH3)2 und Mg(CH3)2 mitgeteilt. Aus beiden Spektren wird abgeleitet, daß mit abnehmender Elektronegativität des Elementes die Bindung zur Methylgruppe immer polarer wird. Damit bekommt die CH-Bindung zunehmenden p-Charakter. Dies trifft weitgehend für die beiden Methylenverbindungen zu.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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