Why is the CO2–CS2 non-ideality larger than in CO2–CCl4? A Raman scattering study

•Raman spectroscopic study of CO2–CCl4 and CO2–CS2 mixtures at 313K.•CO2–CCl4 is found almost ideal and CO2–CS2 strongly non-ideal.•Nano-segregation without demixing in CS2 concentrated mixtures.•A diversity of species are present in CO2 concentrated mixtures.•The connection with the liquid–liquid demixing at lower temperature is discussed.