Studies of phase transition in N-isopropylcarbazole polar molecular crystal

Abstract

A structural phase transition taking place at 140 ± 1 K between two orthorhombic polar phases of N-isopropylcarbazole molecular crystal is reported. The space groups of the low-temperature (118 K) and room-temperature phases are Pbc21 (C2v5) and Iba2 (C2v21), respectively. The crystal is found to exhibit anomalies of thermal expansion, spontaneous polarization and relative dielectric permittivity, related to the phase transition.