Synthesis and single-crystal X-ray diffraction characterization of novel scandium nitrides under high pressures up to 175 GPa

Recently we demonstrated that yttrium forms YN6 and Y2N11 polynitrides at 100 GPa, that feature a unique organization of nitrogen atoms - an anionic N18 macrocycle and a polynitrogen double helix, respectively. However, the polynitride high-pressure chemistry of its III group neighbor, scandium, is still unknown, although being the lightest transition metal, scandium polynitrides are especially promising as high energy density materials (HEDM). Indeed, the theoretical studies predict the formation of high energy density scandium polynitrides at 50-110 GPa with exotic crystal structures. Here, we propose a single-crystal X-ray diffraction study of the Sc-N system at pressures up to 175 GPa at ID11. The aims of the proposed experiments are a synthesis of new Sc-N compounds at megabar pressure, characterization of their crystal chemistry and behavior upon decompression, tests of theoretical predictions, search for regularities in polynitride chemistry, and discovery of novel HEDM.