Table 2. Parameters obtained by fitting a second-order Grüneisen–Debye model with a single Debye temperature [equation (S2)] to the unit-cell volume of α-ammonium carbamate between 4.2 and 180 K.

	V 0 (Å)	K 0/γ (GPa)	θD (K)	Q (J)	b	Adjusted R 2
Second-order	733.15 (1)	49 (1)	208 (5)	3.60 (9) ×10−17	10 (1)	0.99991