We propose a new allotrope of graphane (named as ‘tricycle') with equivalent 4up/2down UUUDUD hydrogenation in each six-carbon ring, which can be considered as the combination of previously proposed 3up/3down chair graphane and stirrup graphane. We find that tricycle graphane is more stable than stirrup graphane and its negative Gibbs free energy (–91 meV/atom) is very close to that of the most stable chair one (–103 meV/atom). Investigations on its vibrational property confirm its dynamical stability. Such a new two-dimensional hydrocarbon may be produced in the process of graphene hydrogenation with a relatively high probability due to its remarkable stability.
Tricycle graphane with 4up/2down (UUUDUD) hydrogenation in each hexagonal carbon ring, which can be considered as the combination of chair (3up/3down: UDUDUD) and stirrup (3up/3down: UUUDDD) graphane.
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