A triatomic carbon and derived pentacarbides with superstrong mechanical properties

Area of Science:

• Materials Science
• Solid-State Physics
• Computational Chemistry

Background:

• Diamond is the hardest known natural material, with Vickers hardness between 90-150 GPa.
• The search for superhard materials with properties exceeding diamond is ongoing.
• Theoretical calculations play a crucial role in predicting novel material properties.

Purpose of the Study:

• To computationally discover and characterize new ultra-hard carbon allotropes.
• To investigate the mechanical properties of novel pentacarbon compounds.
• To identify potential candidates for next-generation high-performance materials.

Main Methods:

• State-of-the-art theoretical calculations were employed.
• Density Functional Theory (DFT) was used for structural and mechanical property predictions.
• Systematic substitution of elements in pentacarbon structures was explored.

Main Results:

• A stable triatomic carbon allotrope was predicted with a Vickers hardness of 113.3 GPa, comparable to diamond.
• A family of pentacarbon compounds (e.g., SiC5, BC5, IrC5, WC5) were identified with Young's modulus ranging from 400-800 GPa and hardness over 40 GPa.
• The triatomic carbon allotrope can transform into a 2D carbon monolayer at high temperatures.

Conclusions:

• The predicted triatomic carbon allotrope and pentacarbon compounds show potential as future high-performance materials.
• These materials could possess properties that challenge or complement diamond.
• Further experimental synthesis and validation are warranted for these computationally discovered materials.