High-Pressure Polymeric Nitrogen Allotrope with the Black Phosphorus Structure

Area of Science:

• Materials Science
• Solid State Physics
• High-Pressure Physics

Background:

• Polynitrogen phases are crucial for fundamental science and developing high energy density materials.
• Understanding nitrogen's behavior under extreme conditions is key to unlocking new material properties.

Purpose of the Study:

• To synthesize and characterize novel polynitrogen phases under high pressure.
• To investigate the structural and electronic properties of nitrogen at extreme densities.

Main Methods:

• Laser heating of pure nitrogen at 140 GPa in a diamond anvil cell.
• In situ characterization using synchrotron single-crystal X-ray diffraction.
• Complementary analysis with Raman spectroscopy and density functional theory calculations.

Main Results:

• Successful synthesis of a polymeric nitrogen allotrope with the black phosphorus (bp) structure, termed bp-N.
• Identification and structural confirmation of bp-N under extreme pressure conditions.
• bp-N aligns nitrogen with heavier pnictogen elements, resolving previous inconsistencies in polymeric nitrogen research.

Conclusions:

• The discovery of bp-N provides critical insights into polynitrogen arrangements at extreme densities.
• This finding opens new avenues for designing advanced high energy density materials.
• The study resolves long-standing questions regarding the nature of polymeric nitrogen phases.