Mobilization and transport of elements in the Earth's crust are important processes for the formation of ore deposits and for global element cycles.

The primary transport mechanisms involve either melts or fluids as mobile phases. Anions play a major role in controlling the transport of cations in fluids by complexation. Most economically interesting elements, including the so called "High Tech Metals" such as Rare Earth Elements, are transported mainly as cations comblexed by anions in fluids. Chlorine and fluorine are the two most abundant halogen elements on Earth and two of the most important anions in geological fluids. Understanding the influence that these elements have on cation transport is therefore crucial. Combining observations on natural systems from the large scale of entire ore deposits to the small scale of electron microscopy with numerical computer modelling provides the most detailed insights into such problems. However, the computer models require input data in form of the physical and chemical properties of the elements of interest under the high pressures and temperatures in the Earth's crust. While some such data are available, tackling new and exiting questions often means that we need to make the relevant data ourselves by laboratory experiments. Especially the complexation of metals critical for high tech applications with fluorine is not well known today and one of the focus points of our group.