Étude de la solubilité et des phases en équilibre dans le système quaternaire réciproque K+, Mn2+/Br−, (H2PO2)−//H2O

Study of solubility and of phases at equilibrium in the K⁺, Mn²⁺/Br⁻, (H₂PO₂)⁻//H₂O system. To elaborate a new method of synthesis of manganese hypophosphite Mn(H₂PO₂)₂·H₂O based on an exchange reaction, the solubility of the phases at equilibrium in the K⁺, Mn²⁺/Br⁻, (H₂PO₂)⁻//H₂O system has been investigated by the isothermal method at 25 °C. For the system under investigation, the two invariants quartets points have been determined, of which compositions are: E₁ – KBr 10.21, MnBr₂ 57.37, Mn(H₂PO₂)₂ 1.35 and H₂O 31.07; E₂ – KBr 3.12, KH₂PO₂ 72.22, Mn(H₂PO₂)₂ 0.12 and H₂O 24.54. The crystallization field of the Mn(H₂PO₂)₂ occupies 91.6% of the total area.     

Étude des structures électroniques de In2O3 pur et dopé avec l’étain

The electronic structures of the sesquioxide In₂O₃ and Sn-doped In₂O₃ are examined both self-consistently within the ab initio local density functional theory and using the non self-consistent extended Hückel method. A direct band gap and a wide dispersion of the bottom of the conduction band are obtained in the non-doped case. In the doped case, a narrow, half-filled band assigned to Sn is found at the bottom of the conduction band, in agreement with the metallic and transparent characteristics observed experimentally.     

Étude des spectres vibrationnels des cyclotétraphosphates

The analysis of the infrared and Raman spectra of a number of cyclotetraphosphates shows that it is possible to characterize the cyclic anion P₄O⁴⁻₁₂. The number, positions and shapes of the infrared absorption bands observed in the symmetric stretching region provide an indication of the symmetry of the P₄O⁴⁻₁₂ ring in each compound.     

Über die Formen des Bibromkampher C10H14Br2O

Ohne Zusammenfassung     

Spectres de vibration des acides oxaliques. I.—Spectres infrarouge et Raman de la phase β des acides H2C2O4, D2C2O4, H2C218O4 et D2C218O4

The infrared and Raman spectra of β phase of H₂C₂O₄, H₂C₂¹⁸O₄, D₂C₂O₄, D₂C₂¹⁸O₁₄ and HDC₂O₄ isotopic species have been investigated at various temperatures (300-30 K) in the 4000-50 cm⁻ range. All the expected (K = 0) lattice modes have been assigned and the amplitudes of R′_x and R′_z librations have been calculated. An assignment for 17 intramolecular fundamentals out of the 18 expected is given. Most of these internal modes show a relatively strong correlation field splitting. The structure of the OH and OD stretching bands is discussed in some detail using the isotope and temperature shifts and the isotopic dilution technique.     

Étude mécanistique et structurale des résines R/F

The follow-up of the advance of the reaction of polymerization of resorcinol with formaldehyde in acid or basic medium by NMR shows that the structure of the obtained xerogel in both cases is the same one. Indeed, the junction between the aromatic nuclei is of type OCH₂OCH₂. While basing itself on the structure of the xerogel, we propose the mechanism for the polymerization reaction between resorcinol and formaldehyde.     

Étude physico-chimique des substances thermomètres

Résumé Les auteurs ont donné un résumé de leurs recherches sur la pyrolyse de 32 substances qui changent de couleur entre 35 et 450° C et qui peuvent s'utiliser comme indicateurs de température. Les courbes de thermolyse ne sont pas reproduites à cause de leur simplicité. Les causes des changements de couleur sont variables. Dans quelques cas, il s'agit d'un changement d'état allotropique (dérivés du mercure) et l'on observe une réversibilité parfaite. Dans d'autres cas, sous l'action d'une reprise d'humidité, on revient à la teinte initiale. Enfin, comme la température de destruction dépend beaucoup du mode de préparation, de la vitesse de chauffe, de l'atmosphère environnante, certaines températures de virage ne doivent pas être considérées comme absolues. C'est pourquoi certaines de nos valeurs s'écartent de celles des auteurs précédents.

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Summary The writers have given a résumé of their investigations of the pyrolysis of 32 substances which change color between 35 and 450° C and which can be employed as temperature indicators. The thermolysis curves are not reproduced because of their simplicity. There are various reasons for these changes in color. In some instances a change in allotropic state is involved (mercury derivatives) and a perfect reversibility is observed. In other cases, the initial color is restored because of the recovery of moisture. Finally, since the temperature of destruction depends greatly on the method of preparation, the rate of heating and the surrounding atmosphere, certain color change temperatures should not be regarded as absolute. This explains the divergence of our values from those of previous workers.

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Zusammenfassung Über die Untersuchungen der Pyrolyse von 32 Substanzen, die zwischen 35 und 450° C ihre Farbe ändern und daher als Wärmeindikatoren dienen können, wird zusammenfassend berichtet. Die Thermolysekurven sind ihrer Einfachheit wegen nicht wiedergegeben. Die Ursachen der Farbänderung sind unterschiedlich. Mitunter handelt es sich um Polymorphien (Quecksilberverbindungen), die vollständig reversibel sind. In anderen Fällen führt die Wiederaufnahme von Wasser auch zur ursprünglichen Farbe. Da die Zersetzungstemperatur weitgehend von der Art der Darstellung des Präparates, der Geschwindigkeit des Erhitzens, der umgebenden Atmosphäre abhängt, sind manche Umwandlungspunkte nicht als Absolutwerte anzusehen. Aus diesem Grund ergaben sich auch Abweichungen gegenüber Angaben anderer Autoren.

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En l'honneur du ProfesseurFrite Feigl, pour son 70^e anniversaire.     

Les composés CoNpF6·3H2O etCoUF6·3H2O: Étude Structurale,mesure des susceptibilités magnétiques et résonance mössbauer (237Np)

CoUF₆·3H₂0 and CoNpF₆·3H₂O were prepared using hydrothermal synthesis (40% HF), Γ = 750 K and P = 2000 bar. They crystallize in the monoclinic system, space group C2. The crystal structure of CoNpF₆·3H₂O was refined to R = 0.030 and R_p = 0.041 for 1999 independent reflections. The neptunium atoms have a coordination of nine (eight fluorine atoms and one water molecule) and the cobalt atoms have a coordination of six (four fluorine atoms and two water molecules). The Np-F distances vary between 2.194(9) and 2.413(8) Å and the Co-F distances vary between 1.959(9) and 2.072(9) Å. The packing consists of infinite chains of neptunium polyhedra sharing two fluorine atoms; these chains are linked to each other by the cobalt atoms. The magnetic susceptibility of CoUF₆·3H₂O follows a Curie-Weiss law (θ = −74(1) K; μ_eff = 7,4(1) μ_B (formula unit)⁻¹). A magnetic transition is observed for the neptunium compound at T_N = 9(1) K (θ = −62(1) K; μ_eff = 6.4(1) μ_B (formula unit)⁻¹). The ²³⁷Np Mössbauer spectrum for this compound was recorded at 4.2 K and shows magnetic hyperfine structure associated with quadrupole splitting. The spectrum was fitted assuming that the principal axes of the magnetic field and the electric field gradient are collinear and that the asymmetry parameter is zero η = 0; H_eff = 3530(6) kOe; e²qQ = −41.2(8) mm s⁻¹; δ = −6.3(4) mm s⁻¹ with respect to NpAl₂; Γ = 4.2(3) mm s⁻¹).     

Étude critique des réactions des cations : Nickel

The authors have tried out the spot tests suggested for the cation nickel between 1937 and 1947. After a critical examination they recommend following the details of the second Report as drawn up by WENGER AND DUCKERT, in particular the use of the dioxime of 1:2-cyclohexanedione, known commercially under the name nioxime.     

Étude critique des réactions des cations : Cobalt

The authors have critically examined the reactions proposed for cobalt between 1937 and 1947. Their findings are in agreement with the conclusions, of the second Report (wenger and duckert). However, the reaction with potassium cyanate can be replaced by the closely similar test, using sodium thosulpliate, a more accessible reagent, there is no interference; from copper, iron and nickel.     

Étude critique des réactions des cations : Uranium

A critical examination has been made of all drop reactions proposed for uranium during the period 1937–1917. In view of the preparation of the fourth Report, it is proposed to retain only the micro-chemical reaction given by an alkaline thiocyanate and sparteine, even in presence of a large excess of iron.     

Étude par spectrographie infrarouge de la structure de l'acide iodique,de l'acide anhydroiodique et des polyiodates alcalins

Résumé L'étude par spectrographie infrarouge entre 2 et 33 des divers produits de déshydratation de l'acide iodique et des nombreux iodates «acides» et «pyroiodates» qu'il donne avec les iodates alcalins montre l'existence de ponts I-O-I analogues à ceux qui existent dans l'anhydride iodique I₂O₅. Ces liaisons se caractérisent dans la région explorée par deux groupes de bandes fortes à 400–460 cm^–1 et à 515–646 cm^–1, c'est-à-dire en dehors des régions d'absorption caractéristiques des groupements IO₂ ou IO₃.

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Summary The infrared spectrographic study between 2 and 33, of various products of dehydration of iodic acid and numerous acid iodates and pyroiodates which it yields with alkaline iodates reveals the existence of I-O-I bridges analogous to those in I₂O₅. In the regions explored, these links are characterized by two groups of strong bands at 400–460 cm^–1 and at 515–646 cm^–1, i. e. beyond the absorption regions characteristic of the IO₂ or IO₃ groups.

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Zusammenfassung Die IR-spektrographische Untersuchung verschiedener durch Wasserabspaltung aus Jodsäure hergestellter Produkte, zahlreicher saurer Salze und mit Alkalijodaten gebildeter Pyrojodate zwischen 2 und 33 zeigt das Vorhandensein von J-O-J-Brücken, wie sie analog im Jodsäureanhydrid J₂O₅ vorliegen. Charakteristisch für diese Bindung sind im untersuchten Bereich zwei starke Bandengruppen bei 400 bis 460 cm^–1 und bei 515 bis 646 cm^–1, das heißt jenseits des Bereiches der charakteristischen Absorption der Atomgruppen JO2 oder JO3.

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En l'honneur du ProfesseurF. Feigl, pour son 70^e anniversaire.     

Synthesis, crystal structure, and photophysical properties of acid (H3O)2[{W6Br8}Br6] · 4H2O

Compound (H₃O)₂[{W₆Br₈}Br₆] · 4H₂O is synthesized by the reaction of polymeric tungsten bromide W₆Br₁₂ with hydrobromic acid in an ethanolic solution. The structure of the compound is a packing of counterions H₃O⁺ and [{W₆Br₈}Br₆]^2? and crystallization water molecules joined with each other by an extended system of hydrogen bonds. The finely crystalline sample of the complex exhibits luminescence, whose spectrum has a broad profile from ??500 nm to more than 950 nm with a maximum at ??715 nm, with an absolute quantum yield of ??0.225. The emission is characterized by the biexponential decay with lifetimes of ??2.2 and ??8.4 ??s.     

Etude cristallochimique des solutions solides Bi6Pb((P1−xVx)O4)4O4 et d'un nouvel oxyvanadate de bismuth et de plomb : Bi6PbV4O20

Synthesis and characterization of a new oxyvanadate Bi₆PbV₄O₂₀ and of Bi₆Pb((P_1−xV_x)O₄)O₄ solid solutions. The anion substitution of (PO₄)³⁻ by (VO₄)³⁻ groups in the Bi₆Pb(PO₄)₄O₄ oxyphosphate led to solid solutions of Bi₆Pb((P_1−xV_x)O₄)₄O₄ compositions and to a new Bi₆PbV₄O₂₀ oxyvanadate. The study by X-ray diffraction was used to define the limits of the solid solution. The substitution of (PO₄)³⁻ by (VO₄)³⁻ groups result in a displacement of the IR absorption bands to lower frequencies.     

Fourier transform infrared studies of 5′-GMP in 2H2O and H2O solutions.

In a previous work (ref. 1) we observed important changes in the 1700–1400 cm⁻¹ region of FTIR spectra in ²H₂O solutions when 5′-GMP concentration increases. These changes can be attributed to the self-association of this mononucleotide. Recently, study of this process has been extended to other regions of the spectrum and to H₂O solution. Fourier deconvolution has been employed in order to resolve the broad band into component bands. Differences have been observed between spectra in H₂O and ²H₂O for the same solute concentration. The possible causes of these differences are indicated.     

Étude critique des réactions des cations : Rhénium

For the reactions proposed for rhenium, the author is in agreement with the conclusions of the “Second Report” (wenger AND duckErt) with one exception, the microchemical test with pyridine seems preferable to that using acridine.     

La règle de Gribbs et l'emploi des réactifs solides

Résumé Cette publication esquisse une rationalisation de l'emploi des solvants en chimie en se basant sur la règle des phases deGibbs. Cette dernière montre l'intérêt des réactifs solides, employés systématiquement en dehors de tout solvant en cours de réaction. Ces idées sont illustrées à titre d'exemple, par un dosage de la spartéine modifié en conséquence et comparé à un procédé classique.

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Summary This paper surveys a rationalization of the use of solvents in chemistry based on the phase rule ofGibbs. The latter demonstrates the value of solid reagents employed systematically in the absence of all solvent during the course of the reaction. This ideas are illustrated by means of an example, namely by a determination of sparteine modified accordingly and compared to a classic procedure.

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Zusammenfassung Die vorliegende Arbeit bringt einen Vorschlag zur Rationalisierung der Verwendung von Lösungsmitteln auf der Grundlage der Phasenregel vonGibbs. Diese zeigt den Vorteil der Verwendung fester Reagenzien ohne jedes Lösungsmittel beim Ablauf der Reaktion. Als Beispiel hierfür dient die entsprechend modifizierte Bestimmung des Sparteins im Vergleich zu einem üblichen Verfahren.

     

Introduction a l'étude des sels basiques insolubles: Étude des courbes de précipitation des sels basiques insolubles. Produits de solubilité des sels basiques et des hydroxydes

A critical study of curves of precipitation of basic salts by alkali hydroxides shows that the irregularities observed on these curves do not always permit the deduction of the constitution of the salt. They indicate nevertheless the appearance of a new phase and this observation explains, in particular, the important number of wrongly defined basic salts which have been observed.The theory of the titre curves leads to the proposal of formulas permitting the calculation of solubility products of basic salts and even those of hydroxides which were determined very accurately by other methods.     

Étude de la distribution des ions sur colonnes échangeuses

Résumé L'auteur étudie la distribution de divers ions seuls ou mélangés sur une résine cationique, par voie semimicro-analytique.

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Summary A column constructed from eight sacks filled with ion exchangers was used to study the distribution of metal ions of various valency from pure solutions or mixtures. If the chlorides of the metals are used in all cases, sodium and ammonium are retained in the first two sacks; magnesium and zinc in all sacks, especially in the first and sixth; iron and aluminium in all, particularly the first and sixth; nickel and cadmium in the first two, particularly the first; thorium in the first sack. These findings, which are independent of the atomic weight and valency, are possibly related to the formation of solvates and their various stabilities.

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Zusammenfassung Mit Hilfe einer Säule, die aus acht mit einem Ionenaustauscher gefüllten Säckchen bestand, wurde die Verteilung von Metallionen verschiedener Wertigkeit aus reinen Lösungen oder Gemischen untersucht. Verwendet man stets Chloride der betreffenden Metalle, so werden Natrium und Ammonium in den beiden ersten Säckchen, Magnesium und Zink in allen Säckchen, insbesondere im ersten und sechsten, Nickel und Cadmium in den beiden ersten, insbesondere im ersten, Eisen und Aluminium in allen, insbesondere im ersten und sechsten, Thorium im ersten Säckchen zurückgehalten. Diese von Atomgewicht und Wertigkeit unabhängigen Ergebnisse stehen möglicherweise mit der Bildung von Solvaten und deren verschiedener Stabilität im Zusammenhang.