Nitrogen-rich Ce-N compounds under high pressure

Area of Science:

• Materials Science
• Computational Chemistry
• Solid State Physics

Background:

• High-pressure synthesis is crucial for discovering novel materials with unique properties.
• Nitrogen-rich compounds are of interest due to their potential as energetic materials.
• Cerium nitrides have been less explored under high-pressure conditions.

Purpose of the Study:

• To computationally propose new high-pressure, nitrogen-rich cerium nitride (Ce-N) compounds.
• To investigate the structural, electronic, and bonding characteristics of these novel phases.
• To assess their potential as high-energy density materials.

Main Methods:

• First-principles calculations were employed to predict stable high-pressure phases.
• Electronic structure and bonding properties were analyzed to understand material stability.
• Energy density calculations were performed to evaluate their potential as energetic materials.

Main Results:

• Four new high-pressure cerium nitride phases (Pmn21-CeN7, Amm2-CeN9, P1̄-CeN10, and P1̄-II-CeN10) were proposed.
• Novel polymeric nitrogen structures, including layered and chain-like units, were identified.
• High energy densities (3.24-3.86 kJ g⁻¹) were predicted, indicating potential as energetic materials.
• P1̄-CeN10 exhibits ultra-incompressibility along the [1 0 0] direction.

Conclusions:

• The proposed cerium nitrides are promising candidates for high-energy density materials.
• The interplay of ionic Ce-N and covalent N-N bonds stabilizes the nitrogen framework.
• Calculated infrared and Raman spectra provide a basis for experimental verification and synthesis.