Table 2. Summary of the Thermal Properties of 1, 1a, 2, and 3.

Polymorph	Formation	Tss (°C)a	Tm (°C)b	ΔH, kJ/mol
1-I	Cryst. or aggregation from water		198.0	72.02
1-II	Cryst. from ethanol		196.3	70.86
1-III	Cryst. from the melt		195.5	62.68
1a-I	Cryst. or aggregation from water		195.8	67.28
1a-II	Cryst. from ethanol and the melt	150–152	189.0 (IIb)	57.19
		(II → IIb)
2	Cryst. from water and the melt		212.8	74.32
3	Cryst. from water and the melt		208.4	69.55

^aPolymorph 1a-II shows solid-state transition with average transition enthalpy of ΔH = 2.9 kJ/mol. Transition temperature reported as peak maximum.

^bReported as peak maximum.