| Abstract
| - A previously published four-parameter empirical equation of state of liquids is modified twice in order toimprove the p, V, T data representation and its physical meaning, respectively. The first modification, asix-parameter relationship with two pressure square-root terms, was applied to 57 liquid compoundsand to 6 mixtures and gives a very good representation (average percentage deviations of specific volumevalues less than 0.3%) of p, V, T data encompassing large pressure domains (0.1 to 1200 MPa). It couldbe useful for engineering applications. The second modified relationship exhibits the same fittingcharacteristics as the four-parameter one, but it has a better physical meaning. This equation containsan adjustable positive coefficient ξ which accounts for the intersections of the (∂α/∂p)T isotherms at highpressure and also for the variations of the “ pressure coefficient ” (∂p/∂T)V as a function of both volumeand temperature. Thermal expansion data may be represented with an average percentage deviationbetter than 5%.
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