Synthesis, crystal structure, thermal analysis, and electrical properties of bis tetrapropylammonium hexachloro-dizincate compound

The present paper accounts for the synthesis, crystal structure, differential scanning calorimetry, vibrational study, and electrical properties of the [N(C3H7)(4)](2)Zn2Cl6 compound. The latter is crystallized at room temperature in the triclinic system ( space group) with the following unit cell parameters: a = 13.736(2), b = 17.044(3), c = 17.334(2), alpha = 68.30(2)A degrees, beta = 75.14(2)A degrees, and gamma = 84.93(3). The atomic arrangement can be described by alternating organic and inorganic layers parallel to the (001) plan, made up of [N(C3H7)(4)](+) groups and [Zn2Cl6](2-) dimers, respectively. In crystal structure, the inorganic layer, built up by Zn2Cl6 dimers, is connected to the organic ones through van der Waals interaction in order to build cation-anion-cation cohesion. The infrared and Raman studies confirm the presence of the organic group tetrapropylammonium and the Zn2Cl6 anion. Concerning the differential scanning calorimetry, it revealed two reversible solid-solid phase transitions of first order: at 327/324 K and 347/343 K (heating/cooling). Besides, the impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. Regarding the temperature dependence of the dc conductivity, it suggests Arrhenius type: sigma (dc) T = B exp(-E (a) /kT). The tetrapropylammonium cations appeared to be the most sensitive to the phase transition.