Thermal stability, low gap energy and high Temperature order–disorder Phase Transition in Hybrid Material: [N (CH₃)₄]₂PdCl₄

Abstract

The crystal compound [N (CH3)4]2PdCl4 was crystallized in the orthogonal system and the space group is P4/mmm and the refined unit cell parameters are a = b = 8.831 Å, c = 11.415 Å. The structure, vibrational spectra and optical properties have been investigated. DSC studies indicate the presence of two phase transitions at higher temperature which confirm the thermal stability of the palladium‐based compound. These transitions have been studied by Raman scattering on single crystals as a function of temperature which confirmed their nature. The assignment of the observed bands is discussed based in the theoretical calculated frequencies by the density functional theory (DFT) method using B3LYP/LanL2DZ basis in the GAUSSIAN‐09 package of programs. The optical properties in the UV–visible region have been deduced and the energy gap has been determined which is equal to 3.11 eV.

Vibrational spectroscopy, electrical, and thermal properties of [N (CH3)4][N(C2H5)4]CoCl4 compound

“…Szklarz et al had noticed that when the value of the entropy is higher than 2 J mol À1 K À1 it is usually considered as an indication of the order-disorder type of a phase transition, if lower to this value the transition is of displacive type. [13] We can conclude that the transitions occurring at T 1 and T 2 are of displacive type. The detailed assignments of all the bands, based in the comparison with similar compounds, [8,14] are listed in the Table 2.…”