Table 3.

Physicochemical data for 4-AQ polymorphs.

Modification	AH I°	AH II (melt)	AH III
Tfus / °Ca
HSM	167		156 – 157.5
DSC (onset) ± 95 c.i.	167.3 ± 0.1		157.1 ± 0.3
ΔfusHb ± 95 c.i. / kJ mol−1	25.4 ± 0.1	22.1 ± 0.2f	20.0 ± 0.5
Ttrsc / °C
HSM		100 – 140
DSC (onset) ± 95 c.i.		116 ± 3
ΔtrsHd to AH I° ± 95 c.i. / kJ mol−1		−3.3 ± 0.1	−5.4 ± 0.6g
Elatt / kJ mol−1 (PBE-G06)	−132.18	−129.00	−127.35
Order of thermodynamic stability
DSC	a (highest)	b	c
Elatt, −273 °C	a (highest)	b	c
density ordere	a (highest)	c	b

^atemperature of fusion,

^bheat of fusion,

^ctransition temperature,

^dheat of transition,

^ederived from computationally generated structures (see Section 3.5) and indexing of XRPD patterns (ESI^† Table S7),

^fcalculated: sum of Δ_fusH_I° and Δ_trsH_II-I°,

^gcalculated: difference Δ_fusH_III and Δ_fusH_I°.