Novel Ultrahard Carbon Allotrope C5 with Mixed sp2/sp3 Carbon Hybridizations.
Crystal chemistry and First Principles Investigations
Samir F Matar*
Lebanese German University (LGU), Sahel-Alma, Jounieh, Lebanon
*Corresponding Author: Samir F Matar, Lebanese German University (LGU),
Sahel-Alma, Jounieh, Lebanon.
Received:
November 28, 2022; Published: December 06, 2022
Abstract
From crystal chemistry rationale and first principles investigations, novel tetragonal carbon allotrope C5 with mixed sp2/sp2–like carbon sites hybridizations is identified as cohesive and stable both dynamically and mechanically with metallic behavior. Charge density distribution is localized at tetrahedral C-sp3 and delocalized with π-like electrons between trigonal C-sp2 leading to metallic like electronic behavior The anisotropic structure resulting from vertically aligned C=C (ethylene –like) along the tetragonal c-axis provide large C33 elastic constant and high Vickers hardness with a magnitude slightly below diamond. The properties of novel simple allotrope should help assessing nanodiamonds with mixed sp2/sp3 C investigated in different fields of materials as electrochemical ones.
Keywords: Diamond; Hardness; Phonons; DFT; Crystal Chemistry
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