Raman investigation of the order-disorder phase transitions in the 2[N(C3H7)4]SbCl4 compound |
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| Institution: | 1. Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, 3 Lavrentiev av., Novosibirsk, Russia;2. Tobolsk Industrial Institute (Branch of Tyumen Industrial University), 626158 Zona Vuzov 5, Tobolsk, Russia;3. Novosibirsk State University, 630090 Pirogova St. 2, Novosibirsk, Russia;4. South Ural State University, Chelyabinsk 454080, Russia;5. Saint Petersburg State University, Institute of Chemistry, 199034 Universitetskaya Nab. 7-9, Saint Petersburg, Russia;6. Kazan Federal University, Alexander Butlerov Institute of Chemistry, Lobachevskogo St. 1/29, 420008 Kazan, Russia;1. Laboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna, Université de Carthage, Tunisia;2. Department of Chemical and Pharmaceutical Sciences and Center for Structural Diffractometry, via Fossato di Mortara 17, I-44121 Ferrara, Italy;3. Laboratoire de Chimie Organométallique de Surface (LCOMS), Ecole Supérieure de Chimie Physique Electronique, 69622 Villeurbanne Cedex, France |
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| Abstract: | The Raman spectra of bis (tetrapropylammonium tetrachloroantimonate (III)) 2(C3H7)4N]SbCl4 compound single crystals were studied in the wavenumber range from 3500 to 50 cm?1 for temperatures between 300 and 415 K. Two phase transitions occurring at 343 (Ttr1) and 363 K (Ttr2) were observed and characterized. The strong evolutions of the Raman shift, half-widths and intensity of many lines associated with the organic cations were observed with discontinuities in the vicinity of the two phase transitions. The most important changes were noticed for the band at 307 cm?1 (at room temperature) assignable to the torsion of CH3 groups of the cations. The spectral characteristics of this band was analyzed and consistently described in the framework of an order–disorder model for the two phase transitions. They allowed us to obtain information relative to the activation energy, the correlation length, and the critical exponent of the mechanism. The decrease of the estimated activation energies for the band 307 cm?1 with the increase in temperature has been interpreted in terms of a change in the reorientation motion of cations. The temperature dependence of the reduced peak intensity allowed for the determination of the critical exponents and evolution of the correlation length on approaching the transition. |
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| Keywords: | Raman spectroscopy Phase transition |
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