Hydrogen-Bonded Ferroelectrics Based on Metal-Organic Coordination

Metal.-organic coordination (MOC)-type ferroelectrics, cobalt(II) (R)-2-methylpiperazine (MPPA) trichloride [(COCl3)-Cl-II(H-MPPA)], was constructed through hydrogen bonds. It is a good ferroelectric candidate with a P-s = 6.8 mu C center dot cm(-2) as high as almost twice that of triglycine sulfate (P-s = 3.5 mu C center dot cm(-2)) and significantly larger than that of KH2PO4 at the low-temperature ferroetectric phase Fdd2. [(COCl3)-Cl-II(H-MPPA)] is the first example of ferroelectric MOC that can really reach the spontaneous polarization status and opens up a new avenue to explore novel MOC-based ferroelectrics.