Repozytorium

Structure and phase transitions in tetramethylammonium tetrabromoindate(III) and tetraethylammonium tetrabromoindate(III) crystals.

Autorzy

Małgorzata Góśniowska

Zbigniew Ciunik

Grażyna Bator

Ryszard Jakubas

Jan Baran

Rok wydania

2000

Czasopismo

Journal of Molecular Structure

Numer woluminu

555

Strony

243-255

DOI

10.1016/S0022-2860(00)00607-4

Kolekcja

Naukowa

Język

Angielski

Typ publikacji

Artykuł

Streszczenie

Two alkylammonium bromoindate(III) crystals: [(CH3)4N]InBr4 and [(C2H5)4N]InBr4 have been studied by differential scanning calorimetry, thermal expansion, dielectric, IR and X-ray diffraction methods. In the tetramethylammonium analogue three thermal anomalies have been detected at 219, 255 and 332 K indicating complex sequence of phase transitions. The tetraethylammonium analogues have revealed one structural phase transition at 225 K. All phase transitions of first-order type are characterised by a large transition entropy indicating a considerable disordering of the high temperature phases of both compounds. The dielectric anomalies accompanying the phase transitions are typical for crystals exhibiting high temperature “rotator phase”. The infrared changes observed at the phase transition point in [(C2H5)4N]InBr4 indicate that the mechanism of this transition is governed by a disordering process of the cationic sublattice.

Słowa kluczowe

Phase transitions, Alkylammonium, Differential scanning calorimetry, Dilatometric measurements, Infrared spectroscopy

Adres publiczny

https://doi.org/10.1016/S0022-2860(00)00607-4

Strona internetowa wydawcy

http://www.elsevier.com

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