Synthesis, crystal structure, thermal and dielectric properties of tetrapropylammonium tetrabromozincate [N(C3H7)4]2[ZnBr4] compound

The new organic-inorganic compound tetrapropylammonium tetrabromozincate [N(C₃H₇)₄]₂ZnBr₄ has been synthesized and characterized by single-crystal X-ray diffraction, differential scanning calorimetry, IR, Raman and impedance measurements. The crystal structure refinement shows that the [N(C₃H₇)₄]₂ZnBr₄ compound is crystallized in the monoclinic system (space group C_2/c) with the following unit cell parameters: a = 33.145(5) Å, b = 14.234(3) Å, c = 15.081(2) Å, β = 110.207(5)° and Z = 8. The structural arrangement of the title compound can be described as an alternation of organic and inorganic layers along the [100] direction. Differential scanning calorimetry disclosed two order-disorder transition phases located at 340 and 393 K. Besides, an analysis of the dielectric constants ɛ' and ɛ″, at several frequencies, shows a distribution of relaxation times. This relaxation is probably due to the reorientational dynamics of alkyl chains.