Тип публикации: статья из журнала

Год издания: 2023

Идентификатор DOI: 10.3390/inorganics11110434

Ключевые слова: rare earths, lanthanum, sulfate, crystal chemistry, thermodynamics, chemical kinetics, dielectrics

Аннотация: <jats:p>A new polymorphic modification of lanthanum sulfate was obtained by thermal dehydration of the respective nonahydrate. According to powder X-ray diffraction, it was established that β-La2(SO4)3 crystallized in the C2/c space group of the monoclinic system with the KTh2(PO4)3 structure type (a = 17.6923(9), b = 6.9102(4), c Показать полностью= 8.3990(5) Å, β = 100.321(3)°, and V = 1010.22(9) Å3). Temperature dependency studies of the unit cell parameters indicated almost zero expansion along the a direction in the temperature range of 300–450 K. Presumably, this occurred due to stretching of the [LaO9]n chains along the c direction, which occurred without a significant alteration in the layer thickness over the a direction. A systematic study of the formation and destruction processes of the lanthanum sulfates under heating was carried out. In particular, the decisive impact of the chemical composition and formation energy of compounds on the thermodynamic and kinetic parameters of the processes was established. DFT calculations showed β-La2(SO4)3 to be a dielectric material with a bandgap of more than 6.4 eV. The processing of β-La2(SO4)3 with the Kubelka–Munk function exhibited low values below 6.4 eV, which indicated a fundamental absorption edge above this energy that was consistent with LDA calculations. The Raman and infrared measurements of β-La2(SO4)3 were in accordance with the calculated spectra, indicating that the obtained crystal parameters represented a reliable structure.</jats:p>

Журнал: Inorganics

Выпуск журнала: Т.11, №11

Номера страниц: 434

ISSN журнала: 23046740

• Basova Sofia A. (Department of Inorganic and Physical Chemistry, Tyumen State University)
• Molokeev Maxim S. (Laboratory of Theory and Optimization of Chemical and Technological Processes, Tyumen State University)
• Oreshonkov Aleksandr S. (School of Engineering and Construction, Siberian Federal University)
• Zhernakov Maksim A. (Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen)
• Khritokhin Nikolay A. (Department of Inorganic and Physical Chemistry, Tyumen State University)
• Aleksandrovsky Aleksandr S. (Institute of Nanotechnology, Spectroscopy and Quantum Chemistry, Siberian Federal University)
• Krylov Alexander S. (Laboratory of Molecular Spectroscopy, Kirensky Institute of Physics, Federal Research Center KSC SB RAS)
• Sal'nikova Elena I. (Departement of Science and Innovation, Northern Trans-Ural Agricultural University)
• Azarapin Nikita O. (School of Natural Sciences, Tyumen State University)
• Shelpakova Natalia A. (School of Natural Sciences, Tyumen State University)
• Müller-Buschbaum Klaus (Center for Materials Research (LaMa), Justus-Liebig-University Giessen)
• Denisenko Yuriy G. (Construction Institute, Industrial University of Tyumen)

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