H. Iloukhani - Faculty of Chemistry, University of Bu Ali Sina, Hamadan, Iran
M. R. Sameti - Departemnt of Chemistry, Faculty of Science , Malayer University, Malayer, Iran
M Rakhshi - Faculty of Chemistry, University of Bu Ali Sina, Hamadan, Iran

Refractive index for binary and ternary mixtures {cyclohexanone(1) +n,n-dimethylacetamide(2) + n,ndiethylethanolamine (3) have been determined over the full range of compositions over the temperature range (298.15 to 318.15K) and the ambient pressure 81.5 kPa , using a thermostated Abbe´refractometer. Refractive index deviations are negative over the mole fraction range for all binary and ternary mixtures and increase with increasing temperatures from (298.15 to 318.15) K.This means that the interaction of like moleculars is stronger than the unlike molecular intractions. The refractive index deviations of binary mixtures have been fitted to the Redlich−Kister and ternary mixture has been fitted to the Cibulka, Jasinski and Malanowski ,Singe et al, Calvo et al. Lorentz–Lorenz , Dale–Gladstone and Eykman equations to determine the coefficients. The experimental data of the condtituent binary and ternary mixtures are analysed to discuss the nature and strength of intermolecular intractions in these mixtures.