Accurate knowledge of thermodynamic properties is essential for the design and optimization of any process in energy and process engineering. They also play an essential role in academic research. Nowadays, these properties are mainly calculated with the help of equations of state, which are usually generated based on experimentally determined property data (e.g. pressure, density, heat capacity, sound velocity, etc.). If such equations are available, they can be implemented in property software packages such as TREND, REFPROP or CoolProp, allowing the user to calculate the required property data at any time and at (theoretically) arbitrary state points.