Temperature coefficients of the refractive index for hydrocarbons and binary mixtures

► Refractive index temperature coefficients dn/dT of 9 hydrocarbons were examined. ► −dn/dT is inversely proportional to molar volumes (Vm) and molecular weights (M). ► −dn/dT of binary mixtures varies linearly with volume and mass fractions. ► Theory derived from the linear relationships of −dn/dT with 1/Vm and 1/M. ► Experimental results are in good agreement with the theory.