The Two-Parameter Version

Observations such as the above have led to the following statement, known as the Two-Parameter Corresponding States Principle CSP) When compared at the same and P values, all fluids demonstrate the same deviation from ideal gas behavior. 

The practical implications of this principle are obvious establishment of the volumetric behavior of one fluid, say Ar, from experimental measurements, suffices for the prediction of such behavior for all other fluids, for which no experimental data are available. 

---

Equations can be fitted to the experimental vapor pressure data for each component using two, three, or more parameters. For example, the two-parameter version is... 

---