The vibrational spectrum of 3-chloropyridine was calculated on the basis of normal coordinate analysis. Quantum optimized (MNDO) geometry was used for spectral calculations. The refined force field and electro-optical parameters are found to reproduce well experimental IR spectrum of liquid 3-chloropyridine. The coordination effect on the ligand vibrational modes was also investigated. The calculated results indicate the presence of some alterations on the ring force field of the molecule in complex formation. (C) 1999 Elsevier Science B.V. All rights reserved.