Crystal structure, phase transitions and Raman scattering in the new non‐centrosymmetric [(C₃H₇)₄N]₃Bi₃Br₁₂ compound

Abstract

A novel tri-tetrapropylammonium dodeca bromobismuthate (III) compound has been synthesized and studied by single-crystal X-ray diffraction, differential scanning calorimetry, and Raman spectroscopy as a function of temperature. At room temperature, the title compound crystalizes in noncentrosymmetric Cc space group which belongs to monoclinic crystal system. The unit cell dimensions are a = 11.083(6) Å, b = 19.100(6) Å, c = 31.146 (3) Å, β = 98.42(0) , and V = 6522.69(9) Å 3 . The crystal package is provided by electrostatic interactions and hydrogen bonds (C-H … Br). Intermolecular interactions present in the grown single crystal were analyzed by Hirshfeld surface and 2D fingerprint plot. The differential scanning calorimetry reveals two reversible phase transitions at 297 and 430 K. The values of the transition entropies suggest that the first is of an order-disorder type, while the second appears as a displacive one. The Raman versus temperature studies show that