Novel high-pressure nitrogen phase formed by compression at low temperature

Raman spectroscopy and powder x-ray diffraction methods have been used to characterize a novel phase of nitrogen which forms on compression from ambient pressure at low temperatures. The new, , phase exhibits an exceptionally wide range of pressure stability from below 1 to 140 GPa, overlapping nine other known phases. On heating, its transformations are different to those observed in other phases, implying that the phase nitrogen adopts depends not only on P-T path, but also on the initial structural configuration, which greatly complicates its phase diagram.