Nonbonding Electron Delocalization Stabilizes the Flexible N₈ Molecular Assembly.

Area of Science:

• Condensed matter physics
• Materials science
• Computational chemistry

Background:

• Electron delocalization significantly influences condensed material properties.
• Exploiting L-electron delocalization in nitrogen compounds is crucial for advancing high-energy-density materials (HEDMs).
• Current HEDMs face challenges in energy efficiency, safety, and environmental impact.

Purpose of the Study:

• To design and investigate a novel all-nitrogen molecule (N8) leveraging L-electron delocalization.
• To explore the potential of N8 for creating environmentally stable, high-performance HEDMs.
• To understand the fundamental electronic interactions enabling the stability and properties of these materials.

Main Methods:

• Theoretical design and computational modeling of the N8 molecule.
• Analysis of electron delocalization within the nitrogen L-shell (π- and lone pair σ-electrons).
• Investigation of molecular conformation, folding energy barriers, and self-assembly into crystalline structures.

Main Results:

• An N8 molecule with a unique lollipop-shaped conformation was designed.
• The molecule exhibits low energy barriers for folding, enabling self-assembly into stable, all-nitrogen crystals.
• These crystals demonstrate superior stability, high energy density, low mechanical sensitivity, and optimal electronic thermal conductivity compared to existing HEDMs.
• The properties are attributed to π- and lone pair σ-electron delocalization and 3D intermolecular networks.

Conclusions:

• The designed N8 molecule and its derived crystals represent a significant advancement in HEDM development.
• L-electron delocalization in nitrogen is a viable strategy for creating stable and high-performance energetic materials.
• This research paves the way for the potential experimental synthesis of novel, environmentally stable all-nitrogen solids.