The application range of the predictive Soave-Redlich-Kwong (PSRK) group contribution equation of state (EOS) for the prediction of vapor-liquid equilibria (VLE) and gas solubilities was extended by the introduction of additional structural groups (epoxides, HF, HI, COS) and fitting of 98 pairs of group interaction parameters to experimental phase equilibrium data. These data were systematically measured for the extension of PSRK, or taken from literature and compiled in the Dortmund Data Bank (DDB). Typical results are presented for various systems. Additionally, new experimental VLE data are given for the binary system propylene oxide + benzene at 323.15 K. The new data were required to fit the interaction parameters between the epoxy and the aromatic CH group.