Single-crystalline polymeric nitrogen

The authors synthesized polymeric nitrogen at pressures above 110 GPa with laser heating above 2000 K. To prove its cubic gauche (cg) structure, the authors have grown single crystals which produced strong reflections at large diffraction angles. The authors found nine peaks in the 2 Theta=35 degrees range with a special diamond anvil cell. All of the peaks agree with the cg-N structure. The authors checked various combinations of gasket materials and heaters to study possible contamination of the polymeric nitrogen by products of the reaction of the hot nitrogen with these materials or diamond anvils, and found that this is not the case. (c) 2007 American Institute of Physics.