Synthesis and Characterization of a Displacement-Type Ferroelectric–Ferroelectric Phase Transition Compound [(NH3)(CH2)3(NH3)]2[InBr6]Br·H2O

Ferroelectric materials have aroused the researchers' great interest due to their wide applications. Here, a displacement-type ferroelectric-ferroelectric phase transition material [(NH3)(CH2)3(NH3)]2[InBr6]Br·H2O (1) with Tc = 143 K was successfully prepared. The ferroelectric phase transition is verified by the characterization techniques such as differential scanning calorimetry, single-crystal structure elucidation, dielectric and ferroelectric measurements. The single-crystal structure elucidation reveals that the displacement and distortion of [(NH3)(CH2)3(NH3)]2+ cations lead to the phase transition from Cmc21 to Pca21. The spontaneous polarizations at 293 and 133 K are 0.15 and 0.12 μC·cm-2, respectively. We expect that this work will help in further exploration of some new ferroelectric materials.