A Switchable Molecular Dielectric with Two Sequential Reversible Phase Transitions: [(CH3)4P]4[Mn(SCN)6]

A new organic-inorganic hybrid switchable and tunable dielectric compound, [(CH3)(4)P](4)[Mn(SCN)(6)] (1), exhibits three distinct dielectric states above room temperature and undergoes two reversible solid-state phase transitions, including a structural phase transition at 330 K and a ferroelastic phase transition with the Aizu notation of mmmF2/m at 352 K The variable-temperature structural analyses disclose that the origin of the phase transitions and dielectric anomalies can be ascribed to the reorientation or motion of both the [(CH3)(4)P](+) cations and [Mn(SCN)(6)](4-) anions in solid-state crystals.