Existence of Real Fluids with a Negative Fundamental Derivative Γ

The gasdynamic behavior of fluids is inverted if a certain thermodynamic property Λ ≡ ρ3c4(∂2υ/∂P2)8/2 is negative. Several different methods of calculation, based on published thermodynamic data and standard equations of state, yield Γ<0 for relatively complex organic compounds.