A Comprehensive Study of the Thermal Behavior of Rare Earth Chloride Hydrates: Resolving Contradictions

Received: 11 January 2024. Accepted: 12 February 2024. Published online: 6 March 2024.Rare earth metal chlorides are used as starting materials on electrochemical synthesis of pure metals. These chlorides are hygroscopic and tend to form hydrates. To resolve the uncertainty of the thermal behavior of the hydrates LaCl3 ∙ 7H2O, NdCl3 ∙ 6H2O, SmCl3 ∙ 6H2O, and YbCl3 ∙ 6H2O, a comprehensive study is carried out. Thermogravimetry, differential scanning calorimetry and mass spectrometry were used to reveal the dehydration and hydrolysis processes over the temperature range of 25–700 ºC. Phase compositions of the initial hydrates, intermediate and final products are investigated by the XRD analysis, Raman and IR spectroscopy. Distinctions in the thermal behavior of the studied hydrates were found. The features must be taken into account when obtaining anhydrous rare earth chlorides and in technological processes with its participation.XRD analysis and Raman spectra were performed using the equipment of the Shared Access Centre ‘‘Composition of compounds”, IHTE, Ural Branch of RAS

AZINE-GRAPHENE-DYAD: SYNTHESIS AND PROPERTIES

This work was supported by the Russian Science Foundation, project № 22-13-00298

DETERMINATION OF 1-ETHYL-3-METHYLIMIDAZOLIUM CHLORALUMINATE IONIC COMPOSITION BY RAMAN SPECTROSCOPY

Получены спектры комбинационного рассеяния (КР) ионной жидкости состава AlCl3 / 1-этил-3-метилимидазолий хлорид ([EMIM]Cl) с мольными отношениями 1; 1,5; 2. По данным спектров определено наличие ионов [EMIM]+, AlCl4- и Al2Cl7-, и установлена тенденция изменения концентрации заряженных частиц в зависимости от содержания AlCl3 в исследуемом электролите.Raman spectra of the AlCl3/1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) ionic liquid with a molar ratio of 1; 1.5; 2 were obtained. According to the Raman spectroscopy data the presence of [EMIM]+, AlCl4- and Al2Cl7- ions were determined. It was established that the charged particles concentration depends on the AlCl3 content in the studied electrolytes

Structure peculiarities of carbon-coated lithium titanate: Raman spectroscopy and electron microscopic study

Li 4Ti 4.92(CrV) 0.04O 12/C composites were synthesized at 800 °C under a flow of argon/acetylene gas mixture taken in the 40:1volumetric ratio. X-ray diffraction (XRD), thermogravimetric analysis (TGA), magnetic susceptibility, Raman spectroscopy, and electron microscopy (TEM) were used to characterize the phase structure, composition, and morphology of the composites. Transmission electron microscopy and Raman spectroscopy confirmed that carbon exists on the surface of the spinel matrix. The composites proved to have a modified structure in comparison with the pristine spinel phase. © 2011 Elsevier Masson SAS. All rights reserved

Conditions of hydrochemical synthesis, composition, and structure of tellurium films

Conditions of the hydrochemical synthesis of thin tellurium fi lms by reduction of an aqueous solution of tellurous acid with hydrazine were determined. The redox potentials of tellurous acid and hydrazine and their difference in relation to pH of the medium and concentration of tellurite ions were calculated. The kinetics of tellurium layer growth on glass-ceramic substrates and the structure, composition, and morphology of the layers were studied. © 2012 Pleiades Publishing, Ltd

Thermodynamic properties and phase equilibriums in ternary alloys of the Al-C-3D-metal systems

The thermodynamic properties of liquid alloys of the 3d-Me-C systems are calculated using the described algorithm and some experimental data. The analysis of own and literary data has allowed to establish the most reliable mixing enthalpies of binary boundary systems Al-3d-metal. This allowed to estimate the thermodynamic properties of ternary alloys of the Al-C-Sc(Ti, V, Cr, Mn, Fe, Co, Ni, Cu) systems by Kohler equation and to find a regularity of its changing

Structural and Vibrational Properties of the Ordered Y₂CaGe₄O₁₂ Germanate: A Periodic Ab Initio Study

DFT calculations with six LDA, GGA, and hybrid functionals have been performed using the CRYSTAL09 code to describe the crystal structure and vibrational spectra of Y₂CaGe₄O₁₂ cyclotetragermanate, a new optical host. Two space groups <i>P</i>4/<i>nbm</i> and <i>Cmme</i> have been considered. The former corresponds to a mixed (0.5 Ca + 0.5 Y) distribution at the octahedral sites found from the results of Rietveld refinement of room temperature powder XRD pattern; the latter refers to the model of crystallographically nonequivalent calcium and yttrium atomic setting in distorted oxygen octahedrons. The most accurate geometry description has been obtained with the WC1LYP and PBE (<i>n</i> = 6) hybrid functionals, while the B3LYP calculation provides the best agreement between the recorded infrared and Raman spectra and their computed counterparts. Assignments of most of the observed bands to vibrational modes are given. The comparison between calculated and experimental frequencies shows a general good agreement for the spectra below 600 cm^–1. The relationship between selected infrared bands and Raman lines, internal vibrations of the [Ge₄O₁₂] unit, and external modes is briefly discussed