Abstract
The refractive index is an important optical property, and it is closely related to density by the Lorentz-Lorenz equation. The present status of the measurements of the refractive index coexistence curve is described with a special attention to alternative refrigerants recently studied. The values of critical refractive index of refrigerants estimated in the various references are tabulated. In case of HFC-32, the density coexistence curve in the critical region calculated from refractive index data is compared with that directly obtained from PVT measurements.
