Carbon
Overview
Carbon occurs in all organic life and is the basis of organic chemistry. This nonmetal also has the interesting chemical property of being able to bond with itself and a wide variety of other elements, forming nearly ten million known compounds. When united with oxygen it forms carbon dioxide, which is vital to plant growth. When united with hydrogen, it forms various compounds called hydrocarbons which are essential to industry in the form of fossil fuels. When combined with both oxygen and hydrogen it can form many groups of compounds including fatty acids, which are essential to life, and esters, which give flavor to many fruits. The isotope carbon-14 is commonly used in radioactive dating.
Notable characteristics
Carbon is a remarkable element for many reasons. Its different forms include the hardest naturally occurring substance (diamond) and one of the softest substances (graphite) known. Moreover, it has a great affinity for bonding with other small atoms, including other carbon atoms, and its small size makes it capable of forming multiple bonds. These attributes are mostly responsible for carbon’s unique ability to form such numerous compounds, in fact, the majority of all chemical compounds.
We Are Carbon Based Life
Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point. Its triple point is at 10 MPa (100 bar), so it sublimates above 4000 K. Thus it remains solid at higher temperatures than the highest melting point metals like tungsten or rhenium, regardless of its allotropic form.
Carbon Not Present during Early Period of Big Bang
Carbon was not created during the initial expansion of the Big Bang. This is due to the fact that it needs a triple collision of alpha particles (helium nuclei), in order to be produced. The universe initially expanded and cooled too fast for that to be possible. It is produced, however, in the interior of stars in the horizontal branch, where stars transform a helium core into carbon by means of the triple-alpha process. It was also created in a multi-atomic state.
Applications
Carbon is a very important component of all known living systems, along with Hydrogen, Oxygen and Nitrogen. Without it, life as we know it could not exist. The major economic use of carbon is in the form of hydrocarbons, most notably the fossil fuel methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Crude oil forms the raw material for many synthetic substances, many of which are collectively called plastics.
Other uses
- The isotope carbon-14 was discovered on February 27, 1940 and is used in radiocarbon dating.
- Graphite is combined with clays to form the ‘lead’ used in pencils.
- Diamond is used for decorative purposes, and also as drill bits and other applications making use of its hardness.
- Carbon is added to iron to make steel.
- Carbon is used as a neutron moderator in nuclear reactors.
- Carbon fibre, which is mainly used for composite materials, as well as high-temperature gas filtration.
Carbon black is used as a filler in rubber and plastic compounds.
- Graphite carbon in a powdered, caked form is used as charcoal for grilling, artwork and other uses.
- Activated charcoal is used in medicine (as powder or compounded in tablets or capsules) to adsorb toxins, poisons, or gases from the digestive system.
- The chemical and structural properties of fullerenes, in the form of carbon nanotubes, has promising potential uses in the nascent field of nanotechnology.
History and Etymology
Carbon was discovered in prehistory and was known to the ancients, who manufactured it by burning organic material in insufficient oxygen (making charcoal). Diamonds have long been considered rare and beautiful. One of the last-known allotropes of carbon, fullerenes, were discovered as byproducts of molecular beam experiments in the 1980s.
The name comes from French charbone, which in turn came from Latin carbo, meaning charcoal. In German and Dutch, the names for carbon are Kohlenstoff and koolstof respectively, both literally meaning “coal-stuff”.
(c) 2009 Bryan Brandenburg
