Encapsulation of Mg₂ inside a C₆₀ cage forms an electride.

Area of Science:

• Computational Chemistry
• Materials Science
• Nanotechnology

Background:

• Fullerenes (C60) are versatile carbon cages with potential for endohedral encapsulation.
• Magnesium dimers (Mg2) are reactive species whose properties can be modified by confinement.

Purpose of the Study:

• To investigate the structural, electronic, and bonding properties of endohedrally encapsulated magnesium dimer within fullerene (Mg2@C60).
• To determine the stability and bonding nature of the Mg2@C60 system using theoretical calculations.

Main Methods:

• Density Functional Theory (DFT) based computational calculations.
• Analysis of minimum energy structures and symmetry.
• Natural Bond Orbital (NBO) analysis for electronic structure.
• Electron density descriptor analysis for bonding characteristics.

Main Results:

• The minimum energy structure of Mg2@C60 exhibits C2h symmetry.
• A significantly shorter Mg-Mg bond length was observed within the C60 cage compared to free Mg2.
• The formation of Mg2@C60 is thermochemically spontaneous.
• NBO analysis indicates an Mg2 2+ fragment with a covalent Mg-Mg bond inside the C60 cage.
• Electron density analysis reveals covalency in the Mg-Mg bond and an ionic interaction between Mg2 and C60.
• A non-nuclear attractor (NNA) was identified between the magnesium atoms.
• The bonding pattern was characterized as [Mg2 2+] and [C60 2-].

Conclusions:

• The endohedral encapsulation of Mg2 within C60 results in a stable system with unique electronic properties.
• The Mg2@C60 system behaves as an electride, characterized by ionic interactions and a confined Mg2 2+ fragment.
• Theoretical insights provide a foundation for designing novel endohedral fullerene materials with tailored electronic characteristics.