Using Equation (47) results in:

(60)

From (60) we have the definition for the fugacity coefficient for the case that the EOS needs *V* and *T* as state variables

(61)

As in Equation (30), we can also write

(62)

or with Equation (29)

(63)

Again, the only prerequisite for the definition of the fugacity coefficient is the ideal gas law. Identical relationships as in Equations (31)-(33) can be formulated by just replacing *P* by *V* in the subscript.