“…In a hydrogen bond type ferroelectric, the hydrogen bonds can be viewed as donor‐acceptor systems (H atoms act as acceptor, while N, O, or halogen atoms are donors). Since H‐bonds are directional but weaker than covalent bonds when binding atoms in molecules, aggregates constructed by H‐bonds easily undergo transformations that are induced by the cleavage and formation of other H‐bonds, by proton transfers, or by disordering . Usually, these hydrogens motions trigger the displace of N, O, or halogen atoms and result the residual polarization for the ferroelectric properties.…”