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Evgeniy, Pogoreltsev
Evgeniy, Bogdanov
Svetlana, Melnikova
Igor, Flerov
Nataly, Laptash
2019-07-01T07:29:16Z
2019-07-01T07:29:16Z
2017-12
Evgeniy, Pogoreltsev. (NH4)3HfF7: Crystallooptical and calorimetric studies of a number of successive phase transitions [Текст] / Pogoreltsev Evgeniy, Bogdanov Evgeniy, Melnikova Svetlana, Flerov Igor, Laptash Nataly // Journal of Fluorine Chemistry. — 2017. — Т. 204. — С. 45-49
00221139
https://www.sciencedirect.com/science/article/abs/pii/S0022113917303445
http://elib.sfu-kras.ru/handle/2311/111326
Single crystals of (NH4)3HfF7 were grown. Polarising optical observations as well as measurement of the heat capacity and birefringence Δn(Т) were performed in the temperature range of 200–310 K. Reversible phase transitions at temperatures T0 =290 K, Т1 =280.5 K, Т2 ≈273 K, Т3 =266 K, Т4 =259 K, Т5 =231 K, Т6 =229 K were found. Observations in polarised light make it possible to suggest a sequence of changes in the symmetry groups for these transitions. The T-p phase diagram was studied and the temperature boundaries of the stability of the distorted crystalline phases were determined. A significant change of the entropy at successive phase transitions ΣΔS =10.6 J/mol K indicates a disordering of the initial cubic phase.
CRYSTAL STRUCTURE
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(NH4)3HfF7: Crystallooptical and calorimetric studies of a number of successive phase transitions
Journal Article
Journal Article Preprint
45-49
29.19
2019-07-01T07:29:16Z
10.1016/j.jfluchem.2017.10.004
Институт инженерной физики и радиоэлектроники
Кафедра теплофизики
Journal of Fluorine Chemistry
Q2
Q2


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