Ferroelectric order of parallel bistable hydrogen bonds.

A new NH.N hydrogen-bonded ferroelectric crystal of [C6H12N2H]+ReO - 4 (dabcoHReO4) exhibits exceptional dielectric properties that result from the unique structure where all the bistable NH...N hydrogen bonds are parallel and directed exactly in the same sense. Consequently, the main structural origin of the spontaneous polarization of the crystal is the identical orientation of the asymmetric NH+...N hydrogen bonds along [001]. This first observation of a ferroelectric with parallel arrangement of the NH+...N bonded aggregates, gives temperature-independent and the highest spontaneous polarization ever reported for an organic or water-soluble substance.