Table 4.

Sums of internal energies, E _HBS,Σ (kJ mol⁻¹), from N–H···O=C bonded structures in polymorphs of Pbtl and their origin from different types of interaction

HBS	Form	N HBS [N o, N t, N n]	E HBS,Σ	E T range (o)	E T range (t)	E n,Σ
C-1	X	2 [0, 2, 0]	−47.5		−47.2 to −47.7
C-2	III	2 [0, 2, 0]	−45.4		−45.4
C-2	I (C)	2 [0, 2, 0]	−48.9		−48.1 to −49.7
C-2	II (C)	2 [0, 2, 0]	−46.9		−46.8 to −47.0
C-3	V	4 [4, 0, 0]	−56.4	−23.1 to −32.9
C-5	VI	6 [2, 1, 3]	−72.0	−28.4 to −34.4	−46.5	−17.3
L-3	I (A + B)	10 [2, 1, 7]	−100.2	−34.0 to −40.5	−49.2	−38.4
L-3	II (A + B)	10 [2, 1, 7]	−98.6	−35.1 to −38.2	−45.7 to −47.5	−38.7

Contributions arise from N _HBS pairwise contacts, of which there are N _o one-point H-bond connections, N _T two-point connections and N _n non-H-bond interactions and ranges of interaction energies E _T (kJ mol⁻¹) for the o- and t-connections involved. E _n,Σ (kJ mol⁻¹) is the sum of all significant (internal) non-H-bonded interaction energies within an HBS (C-5 and L-3 only)