In this paper the results of a Raman study on LiNbO3:Zn crystals are presen
ted. It is found that the symmetry, distribution and relative intensities o
f the vibrational modes show few changes, as compared to the results of pur
e LiNbO3 crystals. Some vibrational modes are coupled to each other by dopi
ng ZnO into LiNbO3 crystals, and the coupling effects disappear gradually w
ith the decrease of temperature. It is suggested that LiNbO3:Zn is substitu
te solution and the doped Zn ions substitute for the Nb-Li first and then t
he Li ions. The observed vibrational modes in LiNbO3 crystals are mainly de
termined by the oxygen octahedra.