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Luila Zaimi
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An organic compound is any member of a large
class of gaseous, liquid, or solid chemical
compounds whose molecules contain carbon. For
historical reasons discussed below, a few types of
carbon-containing compounds such
as carbides, carbonates, simple oxides of carbon
(such as CO and CO2), and cyanides are
considered inorganic.[1] The distinction
between organic and inorganic carbon
compounds, while "useful in organizing the vast
subject of chemistry... is somewhat arbitrary."[2]
Organic chemistry is the science concerned with
all aspects of organic compounds. Organic
synthesis is the methodology of their preparation.
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The word organic is historical, dating to the 1st century. For many centuries,
Western alchemists believed in vitalism. This is the theory that certain
compounds could be synthesized only from their classical elements—earth,
water, air, and fire—by the action of a "life-force" (vis vitalis) that only organisms
possessed. Vitalism taught that these "organic" compounds were fundamentally
different from the "inorganic" compounds that could be obtained from the
elements by chemical manipulation.
Vitalism survived for a while even after the rise of modern atomic theory and the
replacement of the Aristotelian elements by those we know today. It first came
under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a
compound known to occur only in living organisms, from cyanogen.[citation needed] A
more decisive experiment was Wöhler's 1828 synthesis of urea from the
inorganic salts potassium cyanate and ammonium sulfate. Urea had long been
considered an "organic" compound, as it was known to occur only in the urine of
living organisms. Wöhler's experiments were followed by many others, where
increasingly complex "organic" substances were produced from "inorganic"
ones without the involvement of any living organism.
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Even though vitalism has been discredited, scientific nomenclature retains the
distinction between organic and inorganiccompounds. The modern meaning
of organic compound is any compound that contains a significant amount of
carbon—even though many of the organic compounds known today have no
connection to any substance found in living organisms.
There is no single "official" definition of an organic compound. Some textbooks
define an organic compound as one that contains one or more C-H bonds.
Others include C-C bonds in the definition. Others state that if a molecule
contains carbon―it is organic.[3]
Even the broader definition of "carbon-containing molecules" requires the
exclusion of carbon-containing alloys (includingsteel), a relatively small number
of carbon-containing compounds such as metal carbonates and carbonyls,
simple oxides of carbon and cyanides, as well as the allotropes of carbon and
simple carbon halides and sulfides, which are usually considered inorganic.
The "C-H" definition excludes compounds that are historically and practically
considered organic. Neither urea nor oxalic acid is organic by this definition, yet
they were two key compounds in the vitalism debate. The IUPAC Blue Book on
organic nomenclature specifically mentions urea[4] and oxalic acid.
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Other compounds lacking C-H bonds that are also traditionally
considered organic include benzenehexol, mesoxalic acid,
and carbon tetrachloride. Mellitic acid, which contains no C-H
bonds, is considered a possible organic substance
in Martian soil. C-C bond is found in most organic compounds,
except some small molecules like methane and methanol, which
have only one carbon atom in their structure.[6]
The "C-H bond-only" rule also leads to somewhat arbitrary
divisions in sets of carbon-fluorine compounds, as, for
example,Teflon is considered by this rule "inorganic"
but Tefzel organic. Likewise, many Halons are considered
inorganic, whereas the rest are considered organic. For these
and other reasons, most sources believe C-H compounds are
only a subset of "organic" compounds.
In summary, most carbon-containing compounds are organic,
and almost all organic compounds contain at least a C-H bond or
a C-C bond. A compound does not need to contain C-H bonds to
be considered organic (e.g., urea), but many organic compounds
do.
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Natural compounds
Synthetic compounds
Biotechnology
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Natural compounds refer to those that are produced by
plants or animals. Many of these are still extracted from
natural sources because they would be more expensive to
produce artificially. Examples include most sugars,
some alkaloids andterpenoids, certain nutrients such
as vitamin B12, and, in general, those natural products with
large or stereoisometricallycomplicated molecules present
in reasonable concentrations in living organisms.
Further compounds of prime importance
in biochemistry are antigens, carbohydrates, enzymes, hor
mones, lipids and fatty acids, neurotransmitters, nucleic
acids, proteins, peptides and amino acids, lectins, vitamins,
and fats and oils.
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Synthetic compounds[
Compounds that are prepared by reaction of other
compounds are referred to as "synthetic". They may be
either compounds that already are found in plants or
animals or those that do not occur naturally.
Most polymers (a category that includes
all plastics and rubbers), are organic synthetic or semisynthetic compounds.
Biotechnology
Several compounds are industrially manufactured
utilizing the biochemistry of organisms such as bacteria
and yeast. Two examples are ethanol and insulin.
Regularly the DNA of the organism is altered to express
desired compounds, often not ordinarily produced by
that organism. Sometimes
the biotechnologically engineered compounds were
never present in nature in the first place.