Bromocholine bromide is a molecular ferroelectric with moderate phase transition temperature

We showed that the simple organic salt bromocholine bromide is a molecular ferroelectric with a moderate ferroelectric phase transition temperature (329 K). The order–disorder dynamic transition of organic cations results in symmetry breaking from the centrosymmetric paraelectric phase (P2₁/m) to polar ferroelectric phase (P2₁), affording a moderate spontaneous polarization of 1.0 μC cm⁻² for the ferroelectric phase, as well as a switchable SHG signal and pyroelectric property with feasible “on/off” contrasts.