When Soave equipped the Redlich–Kwong EOS with a better, more flexible temperature dependence of the attractive term, he created one of the most popular EOS ever proposed. The RKS equation is a cubic EOS useful for a wide range of substances (even heavy alkanes).

The equation gives decent vapour pressure curves for many compounds; molar volumes and caloric data are usually not represented well.

The critical compression factor of this EOS is fixed. It is not possible for this EOS to match all 3 critical conditions.

adjustable parameters: 3

For mixture calculations the following mixing theories are available:

[1] G. Soave, Chem. Eng. Sci. 27 (1972) 1197.

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