Nitride chemistry of geomaterials: Formation, crystal structures and properties of multinary metal nitrides prepared at high pressures

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The project aims to the preparation of new binary and multinary nitrides from metal-rich melts under high pressures and temperatures and the subsequent characterisation of the obtained compounds. The experiments are preferably designed after the theoretical prediction from the cooperation partner. Characterisation of new compounds comprises the crystal structure and composition, physical properties as magnetic behaviour, electrical resistivity, hardness as well as compression module. The project starts with the investigation of the high pressure phases of the Fe¿N system from previously prepared and well characterised binary phases. After a good understanding of the behaviour of these phases at high pressure and temperature is achieved, the system will be subsequently extended to Fe¿N¿C and Fe¿N¿C¿O. In a further step exemplary compositions involving different 3d-metals and further metallic components will be studied, preferably after preceding theoretical prediction. An important part of the project will deal with the development of adequate inorganic precursor compounds for in-situ experiments in diamond anvil cells and proper nitrogen and oxygen sources for ex-situ pressure preparation experiments in a multi-anvil press. This part involves the study of the physical and chemical properties of these precursors and the optimisation of experimental conditions for the high-pressure phases.