"Proton Dynamics and Ferroelectricity in Anilate Salts" . . . . . . . . . . . . . "Proton Dynamics and Room-Temperature Ferroelectricity in Anilate Salts with a Proton Sponge" . . . . "Ferroelectricity as well as characteristic proton-transfer dynamics are achieved by combining a 2,3,5,6-tetra(2\u2032-pyridyl)pyrazine (TPPZ) molecule with anilic acids (H2xa). Dielectric measurements revealed phase transitions at Tc = 334 and 172 K for bromanilate (Hba\u2212) and chloranilate (Hca\u2212) salts, respectively. The room-temperature ferroelectricity of the (H2-TPPZ)(Hba)2 crystal is evidenced by the slow polarization reversal with modest pyroelectricity. In accord with the observed large deuteration effect, synchrotron X-ray diffraction studies disclosed proton dynamics in an intramolecular N\u00B7\u00B7\u00B7H+\u00B7\u00B7\u00B7N bond of the H2-TPPZ2+ dication and in an O\u2212H\u00B7\u00B7\u00B7O\u2212 hydrogen-bonded cyclic dimer of the ortho-quinoid Hxa\u2212 anions. The disordered (Hxa\u2212)2 dimer in two-fold orientation manifests its double-proton transfer process above Tc, whereas these protons are ordered in the ferroelectric phase. The H2-TPPZ2+ dication acts as a proton sponge by forming two intramolecular N\u00B7\u00B7\u00B7H+\u00B7\u00B7\u00B7N hydrogen bridges between the pyridyl units with a very short N\u00B7\u00B7\u00B7N distance. The dication in the paraelectric state adopts a nonpolar geometry due to the delocalization of the protons over two sites in the respective N\u00B7\u00B7\u00B7H+\u00B7\u00B7\u00B7N bonds. Below Tc, only one of the two protons gets localized, and the resultant acentric H2-TPPZ2+ ion generates the dipole moment responsible for the ferroelectricity." .