New Tl4.86Fe0.82Hf1.18(MoO4)6 ternary molybdate: crystal structure and properties

Novikova, N.E.; Grossman, V.G.; Bazarov, B.G.; Verin, I.A.; Dudka, A.P.; Stefanovich, S.Y.; Bazarova, J.G.

Авторы: Novikova N.E., Grossman V.G., Bazarov B.G., Verin I.A., Dudka A.P., Stefanovich S.Y., Bazarova J.G.
Журнал: Acta Crystallographica Section B: Structural Science
Том: 76
Год издания: 2020
Издательство: Blackwell Publishing Inc.
Местоположение издательства: United Kingdom
Первая страница: 839
Последняя страница: 849
DOI: 10.1107/S2052520620010768
Аннотация: Single crystals of Tl4.86Fe0.82Hf1.18(MoO4)6 (a = b = 10.5550 (3) Å, c = 37.7824 (9) Å, γ = 120°) are obtained by the self-flux method in the Tl2MoO4–Fe2(MoO4)3–Hf(MoO4)2 system. On the curve of differential scanning calorimetry in a range 320–350 K and at T ~690 K, endothermic peaks are observed. The second harmonic generation test shows an excess of the signal of the quartz standard by almost three times at room temperature.In the range 320–340 K, its intensity decreases by almost three times and at T ~700 K it drops to zero.In the same interval, the temperature dependences of the unit cell parameters and volume exhibit features. According to X-ray diffraction data, the crystal structure consists of non-polar and polar domains with different local symmetries.The structureisa three-dimensional frameworkconsistingofalternating(Hf,Fe)O6-octahedraconnectedbyМоО4 tetrahedra. Hf and Fe atoms occupy mixed Hf/Fe positions with different probabilities: 0.77:0.23, 0.50:0.50 and 0.32:0.68. Tl cations are located inside the framework in zigzag channels extended along the a and b axes. The thallium arrangement is disordered, i.e. it involves additional positions and vacancies. The complex crystal structure has been solved using the nonstandard space group R1, taking into account the local symmetry R3c for the Mo atoms and mixed Hf/Fe positions mainly occupied by Hf atoms. The possible paths of ion transport are analyzed. The energy required to overcome the potential barrier between sites of Tl cations to migrate, which corresponds to the activation energy of conductivity, is estimated. The ion current is shown to be most probable in the abplane
Добавил в систему: Стефанович Сергей Юрьевич

	ИСТИНА	Войти в систему Регистрация
	Интеллектуальная Система Тематического Исследования НАукометрических данных
	Главная Поиск Статистика О проекте Помощь

ИСТИНА

Интеллектуальная Система Тематического Исследования НАукометрических данных

New Tl4.86Fe0.82Hf1.18(MoO4)6 ternary molybdate: crystal structure and propertiesстатья

Прикрепленные файлы