Hydrogen-Bonded Ferroelectrics Based on Metal−Organic Coordination

Abstract

Metal−organic coordination (MOC)-type ferroelectrics, cobalt(II) (R)-2-methylpiperazine (MPPA) trichloride [Co^IICl₃(H-MPPA)], was constructed through hydrogen bonds. It is a good ferroelectric candidate with a P_s = 6.8 μC·cm⁻² as high as almost twice that of triglycine sulfate (P_s = 3.5 μC·cm⁻²) and significantly larger than that of KH₂PO₄ at the low-temperature ferroelectric phase Fdd2. [Co^IICl₃(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.