Premières applications du thiocarbohydrazide en chimie minérale

Résumé Les auteurs proposent l'emploi du thiocarbohydrazide en chimie minérale. Ils donnent une première liste d'ions réagissants. Ce réactif apparaît déjà intéressant pour le dosage gravimétrique ou colorimétrique du molybdène en présence de tungstène et d'uranium.

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Summary The authors propose the use of thiocarbohydrazide in inorganic chemistry. They give a preliminary list of reacting ions. This reagent appears to have some interest for the gravimetric or colorimetric determination of molybdenum in the presence of tungsten and uranium.

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Zusammenfassung Die Anwendung von Thiocarbohydrazid in der anorganischen Chemie wird vorgeschlagen und eine Liste der mit dieser Verbindung reagierenden Ionen angeführt. Für die gravimetrische oder kolorimetrische Bestimmung von Molybdän in Gegenwart von Wolfram und Uran scheint das Reagens von Interesse zu sein.

     

Intermediate coupling model description of55Fe and57Fe

The properties of the negative parity states of⁵⁵Fe and⁵⁷Fe are investigated in the framework of the intermediate coupling model. In the model, a neutron or a quasineutron is coupled to anharmonic vibrations of the core. Anharmonicities of the vibrations are estimated through the observed properties of the core. Energy levels, spectroscopic factors and electromagnetic properties have been calculated. The results of the present calculations are also compared with available experimental results and other theoretical results. The model reasonably accounts for many of the properties of the low-lying states.     

Sur le chlorure de formyle

Rèsumè Les auteurs n'ont pu mettre en évidence la bande d'absorption infrarouge du groupement CO vers 1800 cm^–1 relative au chlorure de formyle hypothétique.

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Summary The authors have not been able to establish the infrared absorption band of the CO group in the neighborhood of 1800 cm^–1 relative to the hypothetical formyl chloride.

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Zusammenfassung Die der Carbonylgruppe im hypothetischen Formylchlorid zugehörige Absorptionsbande bei 1800 cm^–1 ließ sich nicht nachweisen.

     

Une contrainte géométrique pour certaines sous-variétés rationnellement convexes

Sans résumé     

Excitation processes leading to ruby emission

We excited the ²T₁-levels in ruby by tunable laser light, pumped bya pulsed YAG:Nd³⁺ laser, and observed the low temperature emissions from the 2$\text{A}$ and $\text{E}$ sublevels of ²E in the mild bottlenecking regime. The R₂-line decay time was about five-fold longer and the ratio of intensities R₂/R₁ higher (by up to a factor 10) than after pumping into ⁴T₂. It is suggested that when ⁴T₂ is pumped the relaxation is nonadiabatic, so that transitions between the sublevels occur while the ²E state relaxes to its normal (trigonal) configuration. The time-development of the relaxing state is studied. It is shown that its coherence between the 2$\text{A}$ and $\text{E}$ sublevels leads to a narrowing of the spectral width in transition between the sublevels.     

Sur la thermogravimétrie des précipités analytiques: Dosage du platine

The authors have studied the thermogravimetric curves of precipitates proposed for the determination of platinum. This precipitated metal is, like gold, sometimes oxidisable, sometimes deposited at constant weight. Bivalent platinum thiophenolate, isolated by the authors, is excellently suitable for gravimetry, after which comes the weighing as platinum (II) chlorides.     

Laser spectroscopy of spinel microcrystallites in a Cr3+ doped silicate glass

Laser spectroscopy of Cr³⁺ ions makes it possible to follow the crystallization process in a cordiente glass (52 SiO₂, 347 Al₂O₃, 12.5 MgO and 08 Cr₂O₃) Absorption and fluorescence are interpreted by structural considerations showing the variation of Cr³⁺ environment during heat treatment Fluorescence line narrowing is performed at 4 2 K giving information on the detailed crystal structure in MgAl₂O₄ spinel microcrystallites formed during heat treatment The splitting of the ²E level is close to 70 cm^?1 and the ¦2D¦ parameter ranges between 0 95 and 1 35 cm^?1 This wide distribution is associated with the well known disordered distribution of Mg²⁺ and Al³⁺ cations in MgAl₂O₄ spinels.     

Analyse organique fonctionnelle : Combinaisons du dimédon (diméthyl-5,5 cyclohexa-nedione-1,3) avec les aldéhydes

The authors have traced and studied the thermolysis curves of dimedone and of the compounds it forms with 26 very different aldehydes. The purity of the aldehydes have been rigorously checked by infrared spectrography.     

Sur la stabilité thermique des étalons analytiques. VI

Twelve substances, which can be used as standards in volumetric analysis were studied, special attontion being paid to the pyrolysis of the three iron salts among these substances.