In this work, the Laser Raman and infrared spectra of the complexes between rare earth nitrates and 15-crown-5 (15-c-5, 1) as well as 18-crown-6(18-c-6, 2) are observed. The red shift of C-O-C stretching vibration frequencies of IR reveals that the coordination may take place. Furthermore, vibration spectra can help us to differentiate the hydrate of heavy rare earth complexes from the anhydrous light rare earth ones, as they have different steric structure. The peak near 875 cm-1 is assigned to the stretching vibration of metal-oxygen ring by coordination of rare earth and crown ether, which is characteristic of the anhydrous light rare earth complexes.

Key words: INFRARED SPECTROPHOTOMETRY, CROWN ETHER COMPOUNDS, RARE EARTH METAL COMPLEX, LASER SPECTROMETRY, RAMAN SPECTROMETRY