Using Raman spectroscopy to understand the origin of the phase transitions observed in [(C3H7)4N]2Zn2Cl6 compound

•This compound is crystallized in the triclinic system with P1¯ space group.•The DSC shows two reversible phase transitions at 327 K and 347 K.•The phase transition has been analyzed by Raman spectroscopy.•Dielectric permittivity confirms the conclusion drawn from the DSC and Raman.

Phase transitions of the centrosymmetric compound, [(C3H7)4N]2Zn2Cl6, were studied by differential scanning calorimetry (DSC), X-ray diffraction, Raman spectroscopy and dielectric measurements. Two reversible order–disorder and displacive phase transitions are observed at T1 = 327 K and T2 = 347 K with 3 K and 4 K hysteresis respectively, indicating a first order character. The evolution of Raman line shifts, “ν”, and the half-width, “Δν”, versus temperature show some singularities associated with the transitions, suggesting that they are governed by the reorientational and the displacement of the organic part. Besides the results of the dielectric permittivity study confirms the conclusion drawn from the calorimetric and Raman measurements that the phase transition located in the vicinity of the temperature of the dielectric proprieties is characterized by change of dynamical state of cation.

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