Phase diagram of a solution undergoing inverse melting

The phase diagram of alpha-cyclodextrin/water/4-methylpyridine solutions, a system undergoing inverse melting, has been studied by differential scanning calorimetry, theological methods, and x-ray diffraction. Two different fluid phases separated by a solid region have been observed in the high a-cyclodextrin concentration range (c >= 150 mg/ml). Decreasing c, the temperature interval where the solid phase exists decreases and eventually disappears, and a first-order phase transition is observed between the two different fluid phases.