Nature of Carbon Bond
As of 2015, over 10 million organic compounds consisting of some combination of
carbon and other elements have been documented, with new organic compounds being
conceived and synthesized every day. The ability of carbon atoms to form covalent bonds with
itself is the most unique of its bonding properties and it is called catenation. This ability of
carbon atoms to combine with other atoms, including itself, enables carbon to form long,
continuous chains, branches and loops consisting of carbon and hydrogen in hydrocarbons and
only carbon in carbon allotropes as shown in figure 1.
Figure 1 Some allotropes of carbon: a) diamond, b) graphite, c) lonsdaleite, d–f) fullerenes (C60,
C540, C70); g) amorphous carbon, h) carbon nanotube.
Interestingly, carbon allotropes span a wide range of physical properties. Diamond is
transparent, the ultimate abrasive, and can be an electrical insulator and thermal conductor.
Conversely, graphite is opaque, a very good lubricant, a good conductor of electricity, and a
thermal insulator. This is the main component of the "lead" in pencils. Allotropes of carbon are
1
, not limited to diamond and graphite, but also include buckyballs (fullerenes), amorphous carbon,
glassy carbon, carbon nanofoam, nanotubes, and others.
Carbon has an affinity for bonding with other small atoms, including other carbon atoms,
via the formation of stable, covalent bonds. In diamond, all the carbon atoms share one electron
with each of their four neighboring carbon atoms. In case of graphite, instead of each carbon
having four neighbours, it only has three. Each carbon shares one electron with two of its
neighbours, and 2 electrons with the third neighbor. In this way, one C-C bond out of three is a
double bond. The atoms all bond together in planes and the planes stack on top of each other.
The key to understanding the various structural, thermal, and electric properties of carbon
nanostructures is the carbon bond, which can be single, double, or triple bond order.
Despite the fact that it is present in a vast number of compounds, carbon is weakly
reactive compared to other elements under normal conditions. At
standard temperature and pressure, it resists oxidation; it does not react with sulfuric acid,
hydrochloric acid, chlorine, or any alkali metals. At higher temperatures, carbon will react
with oxygen to give carbon oxides, and metals to give metal carbides.
New Carbon Structure
Researchers from North Carolina State University have discovered a new phase of solid
carbon, called Q-carbon, which is distinct from the known phases of graphite and diamond. Q-
carbon exhibits a random amorphous structure that is a mix of 3-way (sp2) and 4-way (sp3)
bonding rather than the uniform sp3 bonds found in diamonds. The process for creating Q-carbon
starts with a substrate, such as such as sapphire, glass or a plastic polymer. The substrate is then
coated with amorphous carbon – elemental carbon that, unlike graphite or diamond, does not
have a regular, well-defined crystalline structure. The carbon is then hit with a single laser pulse
lasting approximately 200 nanoseconds. During this pulse, the temperature of the carbon is
raised to 4,000 Kelvin (or around 3,727 degrees Celsius) and then rapidly cooled. This operation
takes place at one atmosphere – the same pressure as the surrounding air. The end result is a film
of Q-carbon, and the process could be controlled to make films between 20 nanometers and 500
nanometers thick.
Q-carbon can be converted to make diamond-related structures at room temperature and
at ambient atmospheric pressure in air, by changing the rate of cooling. These diamond objects
2
As of 2015, over 10 million organic compounds consisting of some combination of
carbon and other elements have been documented, with new organic compounds being
conceived and synthesized every day. The ability of carbon atoms to form covalent bonds with
itself is the most unique of its bonding properties and it is called catenation. This ability of
carbon atoms to combine with other atoms, including itself, enables carbon to form long,
continuous chains, branches and loops consisting of carbon and hydrogen in hydrocarbons and
only carbon in carbon allotropes as shown in figure 1.
Figure 1 Some allotropes of carbon: a) diamond, b) graphite, c) lonsdaleite, d–f) fullerenes (C60,
C540, C70); g) amorphous carbon, h) carbon nanotube.
Interestingly, carbon allotropes span a wide range of physical properties. Diamond is
transparent, the ultimate abrasive, and can be an electrical insulator and thermal conductor.
Conversely, graphite is opaque, a very good lubricant, a good conductor of electricity, and a
thermal insulator. This is the main component of the "lead" in pencils. Allotropes of carbon are
1
, not limited to diamond and graphite, but also include buckyballs (fullerenes), amorphous carbon,
glassy carbon, carbon nanofoam, nanotubes, and others.
Carbon has an affinity for bonding with other small atoms, including other carbon atoms,
via the formation of stable, covalent bonds. In diamond, all the carbon atoms share one electron
with each of their four neighboring carbon atoms. In case of graphite, instead of each carbon
having four neighbours, it only has three. Each carbon shares one electron with two of its
neighbours, and 2 electrons with the third neighbor. In this way, one C-C bond out of three is a
double bond. The atoms all bond together in planes and the planes stack on top of each other.
The key to understanding the various structural, thermal, and electric properties of carbon
nanostructures is the carbon bond, which can be single, double, or triple bond order.
Despite the fact that it is present in a vast number of compounds, carbon is weakly
reactive compared to other elements under normal conditions. At
standard temperature and pressure, it resists oxidation; it does not react with sulfuric acid,
hydrochloric acid, chlorine, or any alkali metals. At higher temperatures, carbon will react
with oxygen to give carbon oxides, and metals to give metal carbides.
New Carbon Structure
Researchers from North Carolina State University have discovered a new phase of solid
carbon, called Q-carbon, which is distinct from the known phases of graphite and diamond. Q-
carbon exhibits a random amorphous structure that is a mix of 3-way (sp2) and 4-way (sp3)
bonding rather than the uniform sp3 bonds found in diamonds. The process for creating Q-carbon
starts with a substrate, such as such as sapphire, glass or a plastic polymer. The substrate is then
coated with amorphous carbon – elemental carbon that, unlike graphite or diamond, does not
have a regular, well-defined crystalline structure. The carbon is then hit with a single laser pulse
lasting approximately 200 nanoseconds. During this pulse, the temperature of the carbon is
raised to 4,000 Kelvin (or around 3,727 degrees Celsius) and then rapidly cooled. This operation
takes place at one atmosphere – the same pressure as the surrounding air. The end result is a film
of Q-carbon, and the process could be controlled to make films between 20 nanometers and 500
nanometers thick.
Q-carbon can be converted to make diamond-related structures at room temperature and
at ambient atmospheric pressure in air, by changing the rate of cooling. These diamond objects
2
