Table 3.

Hydrogen bonds for optimized polymorphs of favipiravir.

D-H...A a	d(D-H), Å	d(H...A), Å	d(D...A), Å	<(DHA), °	ρ(r) b, a.u.	∇2ρ(r) b, a.u.	Eint b, kJ/mol
Orthorhombic Polymorph
O2-H1...O1	1.017	1.602	2.545	152	0.064	0.142	−93.9
N1-H3...O1#1	1.030	1.817	2.836	169	0.035	0.084	−37.8
N1-H2...N3#2	1.024	2.144	2.981	138	0.021	0.062	−18.9
C4-H4...O1#3	1.092	2.386	3.391	152	0.010	0.040	−8.1
C4-H4...F1#4	1.092	2.861	3.447	114	0.001	0.008	−1.0
Tetragonal Polymorph
O2-H1...O1	1.017	1.599	2.543	152	0.064	0.144	−93.9
N1-H3...O1#5	1.029	1.820	2.839	170	0.035	0.083	−37.2
N1-H2...N3#6	1.023	2.202	3.018	135	0.019	0.058	−16.2
C4-H4...O1#7	1.091	2.406	3.381	148	0.010	0.039	−7.8
C4-H4...F1#8	1.091	2.795	3.346	111	0.004	0.019	−2.8

^a Symmetry transformations used to generate equivalent atoms: #1 1−x, 1−y, −1/2+z; #2 −1/2+x, 1/2−y, −1+z; #3 3/2−x, −1/2+y, 1/2+z; #4 1−x, −y, 1/2+z; #5 y, −1/2−x, 1/2−z; #6 1/2+x, −1/2+y,−z; #7 −1/2+y, −x, −1/2+z; #8 −1/2−y, x, −1/2−z. ^b ρ(r)—electron density at bcps; ∇²ρ(r)—Laplacian of electron density at bcps; E_int—energy of an interaction estimated using the correlation proposed in [22] as −0.5V(r).