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Silicon is often used as a substitute for carbon in fictional lifeforms because of its chemical similarities. In cinematic and literary science fiction, when man-made machines cross from non-living to living, this new form is often presented as an example of non-carbon-based life.
In general bonds of carbon with other elements are covalent bonds. Carbon is tetravalent but carbon free radicals and carbenes occur as short-lived intermediates. Ions of carbon are carbocations and carbanions are also short-lived. An important carbon property is catenation as the ability to form long carbon chains and rings. [3]
Biological carbon fixation, or сarbon assimilation, is the process by which living organisms convert inorganic carbon (particularly carbon dioxide, CO 2) to organic compounds. These organic compounds are then used to store energy and as structures for other biomolecules .
Carbon is the fourth most abundant chemical element in the observable universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. [52] Some meteorites contain microscopic diamonds that were formed when the Solar System was still a protoplanetary disk. [53]
The symmetry of a carbon dioxide molecule is linear and centrosymmetric at its equilibrium geometry. The length of the carbon–oxygen bond in carbon dioxide is 116.3 pm, noticeably shorter than the roughly 140 pm length of a typical single C–O bond, and shorter than most other C–O multiply bonded functional groups such as carbonyls. [19]
An autotroph is an organism that can convert abiotic sources of energy into energy stored in organic compounds, which can be used by other organisms.Autotrophs produce complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide, [1] generally using energy from light or inorganic chemical reactions. [2]
A few halocarbons are produced in massive amounts by microorganisms. For example, several million tons of methyl bromide are estimated to be produced by marine organisms annually. Most of the halocarbons encountered in everyday life – solvents, medicines, plastics – are man-made. The first synthesis of halocarbons was achieved in the early ...
Carbon-based fuel is any fuel principally from the oxidation or burning of carbon.Carbon-based fuels are of two main kinds, biofuels and fossil fuels.Whereas biofuels are derived from recent-growth organic matter [1] and are typically harvested, as with logging of forests and cutting of corn, fossil fuels are of prehistoric origin [2] and are extracted from the ground, the principal fossil ...