Table 1. Summary of the order of parameterization and the dependency of hydrogen-bond types in the training set of crystal structures.

Round	Parameterized interaction	Number of parameterization structures†	Additional types present in the parameterization structures‡
1	H4⋯N1	12 (26)
	H4⋯N2	12 (24)
	H4⋯O1	21 (55)
	H4⋯O2	11 (30)
	H2⋯N1	11 (8)
	H2⋯N2	6 (22)
	H2⋯O1	16 (24)
	H2⋯O2	20 (21)
2	H4⋯N3	10 (10)	H4⋯O1
	H4⋯N4	12 (9)	H4⋯O1
	H2⋯N3	10 (11)	H4⋯O2, H4⋯O1, H2⋯O2
	H3⋯O2	5 (8)	H2⋯O1, H2⋯O2
3	H3⋯O1	24 (20)	H3⋯O2
4	H3⋯N1	6 (0)	H3⋯O1
	H3⋯N2	10 (31)	H3⋯O1, H3⋯O2

^†The value in parentheses is the number of crystal structures in the validation set containing this hydrogen-bond combination.

^‡Parameters describing additional hydrogen-bond types present in these structures were fixed at their values from an earlier round of parameterization.