A Potentially New Li-N Alloy at High Pressure

In-situ powder X-ray diffraction patterns of a dense mixture of elemental Li and molecular nitrogen in a diamond anvil cell were recorded using synchrotron radiation. From the changes in the X-ray diffraction features, the formation of molecular complexes was observed at very low pressure. Upon a compression to above 4 GPa in conjunction with annealing by laser heating, an almost uniformly distributed single phase was observed. The X-ray diffraction patterns cannot be explained by any known phases of Li-N2 system. The Xray diffraction pattern, however, bears similarities with that of the theoretically predicted hexagonal LiN3 structure, composed of unusual “N6” rings.