Crystal structure, phase transition and electrical conductivity studies of [(C3H7)4N][SbBr4] compound

The tetrapropylammonium tetrabromidoantimonate (III) [(C 3 H 7 ) 4 N][SbBr 4 ] is a new member of the organic–inorganic hybrid family like perovskite system. This compound crystallizes in the orthorhombic centrosymmetric Pbca space group at room temperature. Its structure can be described by an alternation of organic and inorganic layers parallel to the (001) plan, made up of [(C 3 H 7 ) 4 N] + cations and [SbBr 4 ] − anions. An extensive network of hydrogen bonds ensures the interconnection of the different entities. Greater knowledge on these interactions has been provided based on the Hirshfeld surface analysis and 2D fingerprint plots. The differential scanning calorimetry studies disclose a presence of two phase transitions located at T 1 = 343 K and T 2 = 363 K. The temperature dependence of the Raman spectra of [(C 3 H 7 ) 4 N][SbBr 4 ] single crystals was studied in the wavenumber range from 10 to 3500 cm −1 for temperatures between 303 and 380 K. The strong evolutions of the Raman shift, half-widths and intensity of many lines associated with the organic cation [(C 3 H 7 ) 4 N] + were observed with discontinuities in the vicinity of the two phase transitions, especially for the lines 1024 cm −1 and 1053 cm −1 , respectively. The Nyquist plot (− Z ’’ vs. Z ’) from the complex impedance spectrum showed only one semicircular arc, representing the grain effect in the electrical conduction. The thermal evolution of the conductivity of the grains also presents an Arrhenius-type behavior, revealing that charge carriers have to overcome different energy barriers while conducting and relaxing.