Thermal phase behavior of 1-butyl-3-methylimidazolium hexafluorophosphate: Simultaneous measurements of the melting of two polymorphic crystals by Raman spectroscopy and calorimetry

- We revisit the complex thermal phase behavior of a ionic liquid [C4mim]PF6.
- Melting curves are obtained for the two polymorphic crystals, β and γ.
- The melting point of β and γ is fairly close, that is, ca. 286 K.
- The fusion enthalpy and entropy of γ are significantly larger than those of β.