Molecular structure of 2-aminopyridine-3-carboxylic acid was studied by single crystal X-ray diffraction at 100 K and inelastic neutron spectroscopy (INS) at 20 K. Infrared and Raman spectra at 293 K were also recorded. Molecular geometries and frequencies were calculated for crystal at local density approximation LDA and general gradient approximation GGA methods. The theoretical frequencies were compared with those observed on the INS, infrared and Raman spectral patterns. (c) 2007 Elsevier B.V. All rights reserved.