Raman scattering and alternative current conduction mechanism of the high‐temperature phase transition in [(C₄H₉)₄N]₃Bi₂Cl₉

Abstract

The tri‐tetrabutylammonium nonachlorobibismuthate(III) was found to crystallize in the monoclinic P21/n space group. Two reversible order–disorder phase transitions are observed at 434/430 K and 477/473 K by differential scanning calorimetry technique. The evolution of Raman wavenumber versus temperature shows a remarkable shifting of the bands associated to alkyl chains, suggesting that the phase transition is governed by the reorientational motion of the organic part [(C4H9)4N]+. The analysis of Nyquist plots has revealed the contribution of two electrical active regions corresponding to the bulk mechanism and the distribution of grain boundaries. The AC conductivity is analyzed by different processes: the non‐overlapping small polaron tunneling model proposed as a closely good model for region I and the correlated barrier hopping attributed to the conduction mechanism for region II. Copyright © 2016 John Wiley & Sons, Ltd.

Vibrational Analysis and Electrical Conduction Mechanism Investigations ofOrder Disorder Phase Transitions in [N(C3H7)4]2ZnBr4Compound

“…All these plots are formed by two semi-circles. Thus, the lower frequency dispersion corresponds to the grain boundary and the higher one to the interior grain [27]. In other words, the centers of semicircles that compose the total electric response are centered below the real axis (Z), which confirms the presence of non-Debye type of relaxation in the materials.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XII

“…Trigui et al report Raman scattering as an alternative current‐conduction mechanism of the high‐temperature phase transition in [(C 4 H 9 ) 4 N] 3 Bi 2 C l9 . They find that alkyl chain condition is analyzed by different processes: the nonoverlapping small polaron tunneling model and the correlated barrier hopping attributed to the conduction mechanism . Wang et al presented an in situ high‐temperature Raman spectroscopic study of the structural evolution of Na 2 W 2 O 7 from the crystalline to molten states.…”

“…They find that alkyl chain condition is analyzed by different processes: the nonoverlapping small polaron tunneling model and the correlated barrier hopping attributed to the conduction mechanism. [217] Wang et al presented an in situ high-temperature Raman spectroscopic study of the structural evolution of Na 2 W 2 O 7 from the crystalline to molten states. To validate the structural evolution of Na 2 W 2 O 7 above, Raman activity of vibrations of the crystal and its melt were calculated using DFT and compared with the in situ Raman spectra of Na 2 W 2 O 7 .…”

Crystal structure, phase transitions and Raman scattering in the new non‐centrosymmetric [(C3H7)4N]3Bi3Br12 compound

“…[ 9,10 ] Most of these phase transitions are found to be triggered by the reorientation motion of the cations exhibiting an order–disorder mechanism. [ 11–13 ]…”

“…We have studied lately in our laboratory hybrid materials containing tetra‐alkylammonium cations with chlorobismuthates (III) anions ([(C 3 H 7 ) 4 N] 3 Bi 3 Cl 12 and [(C 4 H 9 ) 4 N] 3 Bi 2 Cl 9 ), which appeared to have interesting dynamic properties. [ 11,21 ] In view of those considerations and in order to explore the mechanism of phase transition in the tetralkylammonium family compounds, we have successfully synthesized the new tri‐tetrapropylammonium dodeca bromobismuthate (III) crystal.…”