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Updated: Jul 17, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Spontaneous liquifaction of isomerizable molecular crystals
E Tombari1, C Ferrari, G Salvetti
1Istituto per i Processi Chimico-Fisici del CNR, 56124 Pisa, Italy.
Abstract:
A lattice vacancy raises the energy of the neighboring (flexible) molecule in a crystal, which may be enough to isomerize it to a tautomer that does not fit the lattice site, thus creating a liquidlike local region embedding the vacancy. Similar regions may appear elsewhere in the lattice and the regions may ultimately merge. Thus a crystal may spontaneously liquefy over a period of hours to years at a temperature below its normal melting point. Simultaneous heat capacity and heat absorption measurements of several such molecular crystals show that they spontaneously liquefy at a temperature far below their reputed melting point, according to a non-exponential rate kinetics and a temperature dependent rate constant, and do not crystallize on cooling.
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