The Ringberg workshop 1995 on unary data for elements and other end-members of solutions

Data for unaries, i.e. elements and compounds, are essential for the modelling of binary and higher order systems. If the set of data for an element is changed than all model parameters in a thermodynamical database that have been assessed using this set of unary data must be reassessed. In the development of thermodynamical databases this is a critical problem, in particular as the modelling of solution phases requires a large number of estimated parameters for metastable and unstable phases, like Cr in an fcc state. Such estimates can be done in many different ways and today different values are used in different research groups. Discussions and arguments about values for unary data have been ongoing for many years but this workshop is the first one dedicated solely to solve this problem. ipants with a background in physics, chemistry, metallurgy, geology and computer software met at the Ringberg castle for a five days workshop on developing models for stable and metastable elements and unary compounds. The result from this workshop will be presented in the following six papers, in this preface the initial ideas will be presented together with some experience from the workshop.