The two lowest energy candidate structures, referred to as R1(P212121) and R2(𝑃 # ) (Figure (k) and 5(l)), both have the carboxylic acid in the cis-isomer conformation forming strong intermolecular hydrogen bonds with nearby molecules in the crystals. The intermolecular hydrogen bonding in R1(P212121) is between the carboxylic acid proton and the pyridine nitrogen from a nearby molecule, similar to the hydrogen bond networks in the rank 2 predicted structure from the prior study, whereas the R2(𝑃 # ) structure exhibits the typical bidentate hydrogen bonds between cis carboxylic acids existing in many other crystal structures with the same chemical group. Eleven molecules in our validation set contain a carboxylic acid group; among those, nine form a double hydrogen bond motif with the carboxylic acid of another molecule in at least one experimentally observed form. The remaining two cases are either zwitterionic (Gabapentin) or form another favorable double hydrogen bond involving the carboxylic acid and another polar chemical group (Ceftizoxime). All candidate structures within the 3.0 kcal/mol energy window have similar hydrogen bond networks in R1(P212121) and/or R2(𝑃 # ).