Repozytorium

Structural characterization, thermal, dielectric, vibrational properties and molecular motions in [C3N2H5]6[Bi4Br18].

Autorzy

Anna Piecha

Ryszard Jakubas

Adam Pietraszko

Jan Baran

Wojciech Medycki

Danuta Kruk

Rok wydania

2009

Czasopismo

Journal of Solid State Chemistry

Numer woluminu

182

Strony

2949-2960

DOI

10.1016/j.jssc.2009.08.007

Kolekcja

Naukowa

Język

Angielski

Typ publikacji

Artykuł

Streszczenie

[C3N2H5]6[Bi4Br18]has been synthesized and characterized by the X-ray (at 293 and 110 K), calorimetric, dilatometric and dielectric measurements. At room temperature it crystallizes in the monoclinic space group, C2/m. A crystal structure consists of disordered imidazolium cations and ordered discrete tetramers of [Bi4Br18]6-. This compound reveals a rich polymorphism in a solid state. It undergoes three solid–solid phase transitions: from phase I to II at 426/423 K (heating–cooling), at 227 K and at 219.5/219 K. A clear dielectric relaxation process is found in the room temperature phase II. Infrared studies of the polycrystalline[C3N2H5]6[Bi4Br18] showed that the , (ring) and modes of the imidazolium cations appeared to be very sensitive to the phase transition. 1H NMR measurements confirmed a key role of the imidazolium cations in the phase transitions mechanisms at low temperatures.

Słowa kluczowe

Imidazolium, Bismuthate(III), Phase transition, Dielectric relaxation, Infrared, 1H NMR

Adres publiczny

https://doi.org/10.1016/j.jssc.2009.08.007

Strona internetowa wydawcy

http://www.elsevier.com

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