The lattice vibrational modes of the Ordered Vacancy Compound CuGa 3 Se 5 have been obtained at 300 K by a combined analysis of infrared reflectivity and Raman spectra. Lines common to both spectra, observed at 48, 64, 105, 142, 187, 200, 218, 250, and 274 cm -1 , were identified with E or B 2 modes. The most intense peak at 166 cm -1 and those observed at 72 and 90 cm -1 , which are only Raman active, are assigned to the A I and B I modes, respectively.
