A displacive-type mechanism, which accounts for the occurrence of ferroelectricity in most inorganic ferroelectrics, is rarely found in molecule-based ferroelectrics. Its role is often covered by the predominant order-disorder one. Herein, we report a lone-pair-electron-driven displacive-type ferroelectric organic-inorganic hybrid compound, [H(2)dmdap][SbCl5] (1; dmdap = N,N-dimethyl-1,3-diaminopropane). The structure of 1 features a typical zigzag chain of [SbCl5](infinity) containing cis-connected anionic octahedra. The compound undergoes a second-order paraelectric-ferroelectric phase transition at 143 K (P2(1)/c <-> Pc) with a saturation polarization of 1.36 mu C.cm(-2) and a coercive field of 3.5 kV.cm(-1) at 119 K. Theoretical study discloses the ferroelectricity mainly originating from the relative displacements of the Sb and Cl ions in the crystal lattice, which are driven by the 5s(2) lone-pair electrons of the Sb-III center. Furthermore, on the basis of analysis, possible routes are suggested to enhance ferroelectric polarization in this class of compounds.
Zhao, W.-P., Shi, C., Stroppa, A., Di Sante, D., Cimpoesu, F., Zhang, W. (2016). Lone-Pair-Electron-Driven Ionic Displacements in a Ferroelectric Metal-Organic Hybrid. INORGANIC CHEMISTRY, 55(20), 10337-10342 [10.1021/acs.inorgchem.6b01545].
Lone-Pair-Electron-Driven Ionic Displacements in a Ferroelectric Metal-Organic Hybrid
Di Sante, D.;
2016
Abstract
A displacive-type mechanism, which accounts for the occurrence of ferroelectricity in most inorganic ferroelectrics, is rarely found in molecule-based ferroelectrics. Its role is often covered by the predominant order-disorder one. Herein, we report a lone-pair-electron-driven displacive-type ferroelectric organic-inorganic hybrid compound, [H(2)dmdap][SbCl5] (1; dmdap = N,N-dimethyl-1,3-diaminopropane). The structure of 1 features a typical zigzag chain of [SbCl5](infinity) containing cis-connected anionic octahedra. The compound undergoes a second-order paraelectric-ferroelectric phase transition at 143 K (P2(1)/c <-> Pc) with a saturation polarization of 1.36 mu C.cm(-2) and a coercive field of 3.5 kV.cm(-1) at 119 K. Theoretical study discloses the ferroelectricity mainly originating from the relative displacements of the Sb and Cl ions in the crystal lattice, which are driven by the 5s(2) lone-pair electrons of the Sb-III center. Furthermore, on the basis of analysis, possible routes are suggested to enhance ferroelectric polarization in this class of compounds.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
