Search for new polynitrogens at extreme pressures using alkali-metal azides

Here we propose to study the synthesis of polynitrogens in Na and K bearing systems, by reacting the azides with molecular N2 at high pressures. We will use laser heated diamond anvil cells (DAC) with toroidal diamonds to explore the pressure range up to 400-500 GPa and temperatures of synthesis up to 3000 K. We will apply extremely brilliant and tightly focused X-ray synchrotron beam of ESR for the monochromatic single-crystal X-ray diffraction in DAC with a large angular opening to obtain the structure and composition (atomic positions and occupancies) of polynitrides as a function of pressure. We expect to synthesize a variety of polynitrogen species (e.g., pentazolate rings) and study their metastability on unloading to ambient pressure. This research will stimulate discoveries of novel polynitrogens recoverable to ambient pressure and refine the computer codes that predict the structure and stability of various polynitrogen species.