Temperature-Triggered Reversible Dielectric and Nonlinear Optical Switch Based on the One-Dimensional Organic–Inorganic Hybrid Phase Transition Compound [C₆H₁₁NH₃]₂CdCl₄

The one-dimensional organic–inorganic hybrid compound bis­(cyclohexylammonium) tetrachlorocadmate­(II) (1), in which the adjacent infinite [CdCl₄]_n^– chains are connected to each other though Cd···Cl weak interactions to form perovskite-type layers of corner-sharing CdCl₆ octahedra separated by cyclohexylammonium cation bilayers, was synthesized. It undergoes two successive structural phase transitions, at 215 and 367 K, which were confirmed by systematic characterizations including differential scanning calorimetry (DSC) measurements, variable-temperature structural analyses, and dielectric and second harmonic generation (SHG) measurements. A precise structural analysis discloses that the phase transition at 215 K is induced by the disorder–order transition of cyclohexylammonium cations, while the phase transition at 367 K derives from changes in the relative location of Cd atoms. Emphatically, both the dielectric constant and SHG intensity of 1 show a striking change between low and high states at around 367 K, which reveals that 1 might be considered as a potential dielectric and nonlinear optical (NLO) switch with high-temperature response characterization, excellent reversibility, and obvious change of states.