Thermal properties and phase transition in the fluoride, (NH4)(3)SnF7

Описание

Тип публикации: статья из журнала

Год издания: 2016

Идентификатор DOI: 10.1016/j.jssc.2016.02.027

Ключевые слова: Phase transition, Fluorides, Heat capacity, Entropy, Thermal expansion, High pressure

Аннотация: Calorimetric, dilatometric and differential thermal analysis studies were performed on (NH4)(3)SnF7 for a wide range of temperatures and pressures. Large entropy (delta S-0=22 J/mol IQ and elastic deformation (8 (Delta V/V)(0)=0.89%) jumps have proven that the Pa-39 Pm-3m phase transition is a strong first order structural transfoПоказать полностьюrmation. A total entropy change of Delta S-0=32.5 J/mol K is characteristic for the order disorder phase transition, and is equal to the sum of entropy changes in the related material, (NH4)(3)TiF7, undergoing transformation between the two cubic phases through the intermediate phases. Hydrostatic pressure decreases the stability of the high temperature Pm-3m phase in (NH4)(3)SnF7, contrary to (NH4)(3)TiF7, characterised by a negative baric coefficient. The effect of experimental conditions on the chemical stability of (NH4)(3)SnF7 was observed. (C) 2016 Elsevier Inc. All rights reserved.

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Издание

Журнал: JOURNAL OF SOLID STATE CHEMISTRY

Выпуск журнала: Vol. 237

Номера страниц: 269-273

ISSN журнала: 00224596

Место издания: SAN DIEGO

Издатель: ACADEMIC PRESS INC ELSEVIER SCIENCE

Авторы

  • Kartashev A.V. (Russian Acad Sci, Siberian Dept, Kirensky Inst Phys, Krasnoyarsk 660036, Russia; Astafijev Krasnoyarsk State Pedag Univ, Krasnoyarsk 660049, Russia)
  • Gorev M.V. (Russian Acad Sci, Siberian Dept, Kirensky Inst Phys, Krasnoyarsk 660036, Russia; Siberian fed univ, Inst Engn Phys & Radio Elect, Krasnoyarsk 660074, Russia)
  • Bogdanov E.V. (Russian Acad Sci, Siberian Dept, Kirensky Inst Phys, Krasnoyarsk 660036, Russia; Krasnoyarsk State Agr Univ, Krasnoyarsk 660049, Russia)
  • Flerov I.N. (Russian Acad Sci, Siberian Dept, Kirensky Inst Phys, Krasnoyarsk 660036, Russia; Siberian fed univ, Inst Engn Phys & Radio Elect, Krasnoyarsk 660074, Russia)
  • Laptash N.M. (Russian Acad Sci, Far Eastern Dept, Inst Chem, Vladivostok 690022, Russia)

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