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organic compounds
2-Aminonicotinic acid, C6H6N2O2, crystallized in the centrosymmetric space group P21/c in the zwitterionic form. Intermolecular N—HO hydrogen bonds with NO distances of 2.652 (2) and 2.807 (2) Å link molecules into two sets of zigzag chains propagating along the b axis. The two sets of chains are crosslinked by C—HO interactions. The dihedral angle between the planes of adjacent molecules in a chain is 9.77 (7)°. An intramolecular N-HO hydrogen bond is also present.