Adiabatic scanning calorimetry was used to study four ionic liquid crystals whose phase sequences include highly
ordered crystal smectic phases (crystal smectic E or T phases). The ionic liquids were based on piperidinium
or morpholinium cations with long alkyl chains; the anions were tetrafluoroborate or hexafluorophosphate.
High-resolution heat capacity and enthalpy data were obtained, from which the total transition heat and latent
heat for the observed phase transitions were determined. All transitions displayed a non-zero latent heat and were
thus found to be first order.