Graphane
Encyclopedia
Graphane is a 2-dimensional polymer
of carbon
and hydrogen
with the formula unit
(CH)n where n is large. Graphane's carbon bonds are in sp3 configuration, as opposed to graphene's sp2 bond configuration, thus graphane is a 2-D analog of cubic diamond
. Graphane is a form of hydrogenated
graphene
. The first theoretical description of graphane was reported in 2003 and its preparation was reported in 2009.
Full hydrogenation
from both sides of graphene sheet results in graphane, but partial hydrogenation leads to hydrogenated graphene.
If graphene rests on a silica surface, hydrogenation on only one side of graphene preserves the hexagonal symmetry in graphane. One-sided hydrogenation of graphene becomes possible due to the existence of ripplings. Since the latter are distributed randomly, obtained graphane is expected to be disordered material in contrast to two-sided graphane. Annealing allows the hydrogen to disperse, reverting to graphene.
p-doped graphane is postulated to be a high temperature BCS theory
superconductor with a Tc above 90 K
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
with the formula unit
Formula unit
A formula unit in chemistry is the empirical formula of an ionic or covalent network solid compound used as an independent entity for stoichiometric calculations. It is the lowest whole number ratio of ions represented in an ionic compound...
(CH)n where n is large. Graphane's carbon bonds are in sp3 configuration, as opposed to graphene's sp2 bond configuration, thus graphane is a 2-D analog of cubic diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...
. Graphane is a form of hydrogenated
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
graphene
Graphene
Graphene is an allotrope of carbon, whose structure is one-atom-thick planar sheets of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term graphene was coined as a combination of graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer...
. The first theoretical description of graphane was reported in 2003 and its preparation was reported in 2009.
Full hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...
from both sides of graphene sheet results in graphane, but partial hydrogenation leads to hydrogenated graphene.
If graphene rests on a silica surface, hydrogenation on only one side of graphene preserves the hexagonal symmetry in graphane. One-sided hydrogenation of graphene becomes possible due to the existence of ripplings. Since the latter are distributed randomly, obtained graphane is expected to be disordered material in contrast to two-sided graphane. Annealing allows the hydrogen to disperse, reverting to graphene.
p-doped graphane is postulated to be a high temperature BCS theory
BCS theory
BCS theory — proposed by Bardeen, Cooper, and Schrieffer in 1957 — is the first microscopic theory of superconductivity since its discovery in 1911. The theory describes superconductivity as a microscopic effect caused by a "condensation" of pairs of electrons into a boson-like state...
superconductor with a Tc above 90 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...