Temperature‐Induced Reversible Phase Transition with Switchable Dielectric Response in a A2BX4‐Type Hybrid Compound: [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3).

Low‐symmetric quasi‐spherical cations have been widely used in halogenometallate hybrids to increase the incidence of stimulus‐responsive crystal structures. In this paper, we successfully used triethylmethylammonium bromide and cadmium bromide for self‐assembly to obtain a A2BX4‐type hybrid compound [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3, 1) showing phase transition temperature (Tc) of 333 K above room temperature. Various‐temperature structures of 1 have been measured by X‐ray diffraction. We conclude, the phase transition property of 1 induced by thermal stimulation stems from the thermal ellipsoids of the [TEAMA]+ become strikingly larger with the increase of the temperature. The dynamics of the dipoles is the key to construct hybrid molecule‐based switchable dielectrics by motional changes of polar components at different phases. Furthermore, the dielectric properties have also been mentioned and discussed in great detail. [ABSTRACT FROM AUTHOR]