Carbon Substitution on N₂₄ Cages: Crossover between Triangular and Hexagonal Structures

Abstract

Complex forms of nitrogen are of interest for their potential as high-energy materials, but many all-nitrogen systems lack the stability for practical high-energy applications. Inclusion of carbon atoms in an otherwise all-nitrogen structure can increase stability. Nitrogen cages are known for energetically preferring cylindrical structures with triangular endcaps, but carbon cages prefer the pentagon-hexagon structure of the fullerenes. Previous calculations on N 22 C 2 have shown that carbon inclusion narrows the gap between triangular and fullerene-like structures. In the current study, three isomers of N 24 are used as frameworks for carbon substitution. Theoretical calculations are carried out on isomers of N 20 C 4 , N 18 C 6 , and N 16 C 8 , with the goal of determining what level of carbon substitution causes the carbon fullerene-like structures to become energetically preferred.