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Your search keyword '"Svetlana S. Volkova"' showing total 6 results
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6 results on '"Svetlana S. Volkova"'

1. Negative thermal expansion in one-dimension of a new double sulfate AgHo(SO4)2 with isolated SO4 tetrahedra

Author

Zheshuai Lin, Klaus Müller-Buschbaum, Yuriy G. Denisenko, Alexander E. Sedykh, Naizheng Wang, Maxim S. Molokeev, Xingxing Jiang, Victor V. Atuchin, Oleg V. Andreev, Aleksandr S. Aleksandrovsky, Alexander S. Krylov, Aleksandr S. Oreshonkov, and Svetlana S. Volkova

Subjects
Materials science, Polymers and Plastics, Infrared, Mechanical Engineering, Metals and Alloys, Analytical chemistry, 02 engineering and technology, Crystal structure, Atmospheric temperature range, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Thermal expansion, 0104 chemical sciences, Crystal, Negative thermal expansion, Mechanics of Materials, Materials Chemistry, Ceramics and Composites, 0210 nano-technology, Luminescence, Monoclinic crystal system
Abstract

A double holmium-silver sulfate was obtained for the first time. The temperature intervals for the formation and stability of the compound were determined by differential scanning calorimetry. The crystal structure of AgHo(SO4)2 was determined by Rietveld method. The X-ray diffraction (XRD) analysis showed that the compound crystallizes in the monoclinic syngony, space group P21/m, with the unit cell parameters a = 4.71751 (4) A, b = 6.84940 (6) A and c = 9.89528 (9) A, β = 95.1466 (4)°, V = 318.448 (5) A3, Z = 2, RB = 1.55 %, T = 303 K. Two types of sulfate tetrahedra were found in the structure, which significantly affected the spectral properties in the infrared range. In the temperature range of 143−703 K, a negative thermal expansion along the b direction accompanied by a positive thermal expansion along the a and c directions was observed. It was established that negative thermal expansion is the result of the deformation of sulfate tetrahedra, which is affected by the movement of holmium and silver atoms. The excitation in the blue spectral range (457.9 nm) produces a luminescence in light blue (489 nm), green (545 nm) and red (654 nm) spectral ranges, and the latter two were of comparable intensity that is favorable for WLED sources. The observed luminescent band distribution is ascribed to the specific crystal field at Ho3+ ion sites rather than a variation of radiationless probability.

Published
2021

2. Quaternary Selenides EuLnCuSe

Author

Maxim V, Grigoriev, Leonid A, Solovyov, Anna V, Ruseikina, Aleksandr S, Aleksandrovsky, Vladimir A, Chernyshev, Dmitriy A, Velikanov, Alexander A, Garmonov, Maxim S, Molokeev, Aleksandr S, Oreshonkov, Nikolay P, Shestakov, Alexey V, Matigorov, Svetlana S, Volkova, Evgeniy A, Ostapchuk, Alexander V, Kertman, Thomas, Schleid, and Damir A, Safin

Subjects
Models, Molecular, Selenium, Molecular Structure, X-Ray Diffraction, Organometallic Compounds, Crystallography, X-Ray, Lanthanoid Series Elements, Powder Diffraction
Abstract

In this work, we report on the synthesis, in-depth crystal structure studies as well as optical and magnetic properties of newly synthesized heterometallic quaternary selenides of the Eu

Published
2021

3. Europium Oxysulfate Eu2O2SO4 Crystal Structure

Author

Yu. G. Denisenko, Svetlana S. Volkova, Oleg V. Andreev, Nikolay A. Khritokhin, and Nikita O. Azarapin

Subjects
Materials science, Materials Science (miscellaneous), Infrared spectroscopy, chemistry.chemical_element, Crystal structure, 010402 general chemistry, 010403 inorganic & nuclear chemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, Crystallography, chemistry, Group (periodic table), Tetrahedron, Physical and Theoretical Chemistry, Sulfate, Europium, Powder diffraction, Monoclinic crystal system
Abstract

The europium oxysulfate crystal structure was solved by X-ray powder diffraction. The compound crystallizes in monoclinic crystal system. The unit cell parameters are a = 13.6952(1) A, b = 4.1929(4) A, c = 8.1393(2) A, β = 107.455(4)°, space group C2/c. The three major structural elements are recognized to be Eu atoms, SO4 tetrahedra, and μ-O atoms, and their coordination environments were analyzed. The specific structural elements are infinite screw chains composed of trigonal prisms [EuO9]; sulfate tetrahedra [(SO4)Eu8] enclosed into cubes built of europium atoms; and infinite chains composed of tetrahedra [OEu4]. Rationale was given to the splitting of the IR absorption bands corresponding to the vibrations of sulfate groups.

Published
2019

4. Structure, Thermal Stability, and Spectroscopic Properties of Triclinic Double Sulfate AgEu(SO4)2 with Isolated SO4 Groups

Author

Victor V. Atuchin, Alexander S. Krylov, Svetlana S. Volkova, Aleksandr S. Oreshonkov, Aleksandr S. Aleksandrovsky, Maxim S. Molokeev, Yuriy G. Denisenko, and Oleg V. Andreev

Subjects
Chemistry, Monte Carlo method, Structure (category theory), 02 engineering and technology, Crystal structure, Triclinic crystal system, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, Physical chemistry, Thermal stability, Physical and Theoretical Chemistry, Sulfate, 0210 nano-technology
Abstract

Silver–europium double sulfate AgEu(SO4)2 was obtained by solid-phase reaction between Ag2SO4 and Eu2(SO4)3. The crystal structure of AgEu(SO4)2 was determined by Monte Carlo method with simulated ...

Published
2018

6. Synthesis of Samarium OxysulfateSm2O2SO4 in the High-Temperature Oxidation Reaction and Its Structural, Thermal and Luminescent Properties

Author

Maxim S. Molokeev, E.I. Sal’nikova, Svetlana S. Volkova, Alexander S. Krylov, Yu. G. Denisenko, N. A. Khritokhin, Oleg V. Andreev, Victor V. Atuchin, Aleksandr S. Oreshonkov, S.A. Basova, and Aleksandr S. Aleksandrovsky

Subjects
Materials science, oxysulfate, Enthalpy, Pharmaceutical Science, chemistry.chemical_element, Infrared spectroscopy, Crystal structure, Kinetic energy, Article, Analytical Chemistry, lcsh:QD241-441, lcsh:Organic chemistry, Drug Discovery, luminescence, Thermochemistry, thermochemistry, structure, samarium, Physical and Theoretical Chemistry, Organic Chemistry, Temperature, Atmospheric temperature range, Samarium, chemistry, Chemistry (miscellaneous), Thermodynamics, Molecular Medicine, Physical chemistry, Luminescence, Oxidation-Reduction
Abstract

The oxidation process of samariumoxysulfide was studied in the temperature range of 500&ndash, 1000 &deg, C. Our DTA investigation allowed for establishing the main thermodynamic (∆H&ordm, exp = &minus, 654.6 kJ/mol) and kinetic characteristics of the process (Ea = 244 kJ/mol, A = 2 &times, 1010). The enthalpy value of samarium oxysulfate (&Delta, H&ordm, f (Sm2O2SO4(monocl)) = &minus, 2294.0 kJ/mol) formation was calculated. The calculated process enthalpy value coincides with the value determined in the experiment. It was established that samarium oxysulfate crystallizes in the monoclinic symmetry class and its crystal structure belongs to space group C2/c with unit cell parameters a = 13.7442 (2), b = 4.20178 (4) and c = 8.16711 (8)&Aring, &beta, = 107.224 (1)&deg, V = 450.498 (9)&Aring, 3, Z = 4. The main elements of the crystalline structure are obtained and the cation coordination environment is analyzed in detail. Vibrational spectroscopy methods confirmed the structural model adequacy. The Sm2O2SO4luminescence spectra exhibit three main bands easily assignable to the transitions from 4G5/2 state to 6H5/2, 6H7/2, and 6H9/2 multiplets.

Published
2020

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