PVT Properties of Water and Mercury

The PVT properties of water and mercury have been measured up to 8000 bar between 30 and 150°C with an accuracy of 0.01% of the volume by electromagnetically detecting the change in length of a column of fluid. Numerical differentiation yields thermal expansion coefficients and compressibilities accurate to 0.5% for water and 1.0% for mercury. The first and second derivatives of entropy with respect to volume for mercury are consonant with a hard sphere model, though (∂2U / ∂2)T requires a softer repulsive potential. Water, because of its structure, only approaches such a simple model above our maximum temperature.