Multiparameter equations of state — recent trends and future challenges

The purpose of this article is to update the common knowledge on characteristic features of empirical multiparameter equations of state, to increase the confidence of potential users, and possibly to attract other scientists to theoretical and experimental work that is relevant for the future development of these kinds of thermodynamic property models. To do so, the most important features of current multiparameter equations of state and of the algorithms which are used to develop such formulations are briefly explained. Future challenges are outlined with regard both to the development of multiparameter equations of state and to the underlying experimental basis. Relevant references are given for further studies.