Diagramme de phases du système Tl2OMoO3

Six thallium(I) molybdates with numerous allotropic modifications have been found in the binary system Tl₂OMoO₃; Tl₄MoO₅, Tl₂Mo₂O₇, Tl₈Mo₁₀O₃₄ (three forms), and Tl₂Mo₇O₂₂ (two forms) melt incongruently; Tl₂MoO₄ and Tl₂Mo₄O₁₃ which are trimorphic melt congruently. For the most part, the compounds were characterized by their powder diagram and by their IR spectrum which allowed comparisons with alkaline molybdates.     

Etude du système Li0,5Ga2,5O4CuGa2O4 par spectrométrie IR et diffraction de neutrons

The phase diagram of the system (1 − s) Li_0·5Ga_2·5O₄−s CuGa₂O₄ has been established by quenching, DTA, X-ray diffraction at high temperature and IR spectrometry. The change from the disordered (space group P4₃32) to the ordered cubic form (space group Fd3m) is made by means of an extensive biphase (0·25 ⩽ s ⩽ 0·52). The thermal stability of copper and mixed gallates has been studied by thermogravimetric analyses. The spectrum of Cu²⁺ in spinels (0·8–2·5 μ, s ⩾ 0·54) discloses copper on A and B sites. The cation distribution is deduced from neutron diffraction.     

Diagramme de phases du système Ag2Te-In2Te3

The phase diagram of the Ag₂Te-In₂Te₃ quasibinary system was established by differential thermal analysis and X-ray diffraction, in particular by the Guinier — Lenné method. This study confirms the existence of three intermediate ternary phases: AgInTe₂, which crystallizes in a chalcopyrite-type structure and possesses a homogeneity range, undergoes a peritectic decomposition at 650 °C; AgIn₅Te₈, which possesses a large homogeneity range, shows a phase transition at 699 °C and congruently melts at 725 °C; Ag₃In₉₇Te₁₄₇, which crystallizes in a cubic structure, incongruently melts at 672 °C.     

Caractérisation de la solution solide In1−xLi3xVO4 (0 < x ≤ 0,4) dans le système InVO4Li3VO4 et examen des systèmes CrVO4Li3VO4 et InVO4CrVO4

In the InVO₄Li₃VO₄ system, a continuous solid solution In_1−xLi⁽⁶⁾_a□⁽⁶⁾_bLi⁽⁴⁾_c□⁽⁶⁾_dVO₄ exists between InVO₄ and In_0.6Li_1.2VO₄, with a + b = x, c + d = 1, and a + c = 3x. The solid solution is of two types: in the first, 0 < x ≤ 0.33, a = 0, interstitial Li⁺ ions are in the vacant tetrahedral sites of InVO₄; in the second, 0.33 < x ≤ 0.4, c = 1, Li⁺ ions are also in the octahedral sites vacated by In³⁺. The ionic conductivity measured for some compositions is weak, 10⁻⁷ (Ω cm)⁻¹ at 493 K. Solid solution has not been found between CrVO₄ and Li₃VO₄, although CrVO₄ is isostructural with InVO₄. Mutual solid solution between CrVO₄ and InVO₄ is extremely limited. Yellow and weakly hygroscopic monocrystals have been synthetized for R₂Li₃(VO₄)₃ compositions (R = In,Cr,Fe); their chemical formula can be symbolized by LiVO₃: R³⁺. The R³⁺ percentage was too low to be detected by analysis of electronic densities based on X-ray diffraction intensities.     

Système AsGeTe: II. Diagramme de phase du système ternaire AsGeTe

The AsGeTe system is formed by three independent triangles, corresponding to the two quasibinary systems GeAsGeTe and As₂Te₃GeTe. The presence of four phases As₂Ge_nTe_3+n (n = 1 to 4) having peritectic decomposition introduces eight ternary peritectic invariants, whose temperatures and compositions are described. The three ternary eutectics have the following characters: E₁, As₁₉Ge₅₂Te₂₉ (662°C); E₂, As₄₂Ge₅Te₅₃ (368°C); E₃, As₂₂Ge₅Te₇₃ (350°C).     

Etude du phénomène de dépiégeage des ondes de densité de charge dans les systèmes de basse dimensionnalité

Numerical results of the behaviour of a low dimensional system show that the electric resistivity depends on the friction coefficient generated by the defects. We also show that the electric field dependence of the response time at different friction coefficients follows a power law. The divergence of the charge density wave response time near the threshold field indicates that depinning may be viewed as a dynamical critical phenomenon.     

Interactions intramoleculaires—XXXI. Etude vibrationnelle des conformères de chloro-4 et de cyano-4 cyclohexénes alkylés en 3

Infrared and Raman spectra in the liquid state of 3-R, 4-X cyclohexenes (R = CH₃, (CH₃)₃C; X = CN,Cl) and their d₁-(4) and d₃-(3,6,6) isotopic modifications, Raman spectra of some low temperature crystallised compounds, vibrational spectra in the solid state of cis and trans 1-acetoxy 3-t-butyl 4-cyano cyclohexenes, were studied.The frequencies of cyclohexenic skeleton modes below 900 cm⁻¹ and the frequencies of deformation modes involving the CCN bond or stretching νCCl vibration of the different conformers were assigned. In the cis and trans 1-acetoxy 3-R 4-cyano cyclohexenes (respectively in the e′a and e′e conformations), the positions of the 627 cm⁻¹ δ_ax and the 538 cm⁻¹ δ_eq deformation vibrations agree with the assignments proposed for the other cyano derivatives.     

Etudes sur le système ternaire SnInS. Analyses thermique differentielle et radiocristallographique du pseudobinaire SnSIn2S3. Croissance en phase vapeur et caractérisation de composés a valences mixtes de l'étain

The SnInS ternary system has been studied using two different methods of crystal synthesis. By direct combination of the two sulfides (SnS and In₂S₃) various melts have been prepared, and the ternary phase diagram determined by differential thermal analysis. Three ternary phase are found: In₂Sn₂S₅, In₂SnS₄, and In₁₂Sn₅S₂₃. Chemical vapor transport (CVT), using iodine as transport gas, leads to different crystal morphologies (needles, sheets, and polyhedra) according the ratio of iodine to reagent. Several methods have been used to characterize the crystals, specifically X-ray diffraction, electronic microscopy, and Mössbauer spectrometry. The latter shows that both Sn(II) and Sn(IV) are present in all the crystals prepared by CVT.     

Etude structurale d'énoxysilanes—II. Cacul des modes normaux de vibration et du champ de forces de valence du triméthylsiloxyéthylène [(CH3)3SiOCHCH2] et de ses homologues deutériés [(CD3)3SiOCHCH2 et (CH3)3SiOCDCD2]; determination des conformations

The detailed analysis of the vibrational spectra of trimethylsiloxyethylene: [(CH₃)₃SiOCHCH₂] and his deuterated derivatives [(CD₃)₃SiOCHCH₂ and (CH₃)₃SiOCDCD₂] leads to the complete assignment of the observed frequencies.The computation of the valence force field and of the normal modes of vibration in various structural hypotheses shows that these compounds exist in a preferential plane s-trans conformer, the minor one being gauche.     

Etude comparée des spectres de vibration du tiapride. Base et chlorhydrate

Raman and infrared spectra of tiapride were recorded from 4000 to 200 cm⁻¹. Assignments of the fundamental vibrations involved in intra or intermolecular H-bonds as NH⋯O, N⁺H⋯O and N⁺H⋯Cl⁻ are discussed. Analysis of some characteristic vibrations leads to the conclusion that the conformations are quite independent of the solvent effects. The change from tiapride base to chlorhydrate that occurs during the crystallization involves a new order of the aliphatic chain which changes the planarity of the chelated form.     

Synthèse de nouveaux dérivés du 1-hydroxyindole et du pyrazole

New 1-hydroxyindole derivatives have been synthesised by alkylation, acylation reactions and by condensation with acetylacetone and dehydroacetic acid. Action of hydrazines on 3-acetyl-1-hydroxy-indole leads to new pyrazole derivatives.     

Etude par spectroscopie (IR et Raman) de l'éthylène diammonium bis dihydrogénomonophosphate NH3(CH2)2NH3(H2PO4)2

Infrared and Raman Spectra of single crystal and polycrystalline samples of NH₃(CH₂)₂NH₃(H₂PO₄)₂ and of its deuterated polycrystalline derivative have been recorded at 298 K. All the observed bands have been assigned using group theory. The IR and Raman spectra are consistent with the presence of strong OH⋯O hydrogen bonds.     

Etude par RMN de composés organiques contenant des chalcogènes—IX.* RMN du 13C dans des dérivés aromatiques du tellurényle

In order to synthesize new tellurium heterocycles, we prepared o-halogenotellurobenzoyl chlorides. We present and discuss here the results of a ¹³C NMR study of these compounds, together with other intermediates that we have isolated during our synthesis and two new tellurium heterocycles.