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Line 35: − + + + − Benzene is a cyclic compound with a cyclic cloud of delocalized electrons above and below the plane of the rings, due to this, all the c-c bond have the same length. This compound is also stable as a result of its resonance energy(36kcal/mol or 151kJ/mol) − − + − + − +
→Aromatic Compounds
==Aromatic Compounds==
==Aromatic Compounds==
The most common aromatic compound( benzene) was first discorvered by [[W:Michael Faraday|Michael Faraday]] who extracted the compound from a liquid residue obtained after heating whale oil to produce gas used to illuminate buildings. Chemists called the name pheno from the greek name phainein which means "to shine". The early scientist called it aromatic because of the pleasant smell, in this way we distinguish aromatic compoinds from aliphatuc which has higher number of hydrogen to carbon ratio.
The most common aromatic compound (benzene) was first discorvered by [[W:Michael Faraday|Michael Faraday]] who extracted the compound from a liquid residue obtained after heating whale oil to produce gas used to illuminate buildings. Chemists called the name pheno from the greek name ''phainein'' which means "to shine". The early scientists called it aromatic because of the pleasant smell, in this way we distinguish aromatic compoinds from aliphatuc, which has higher number of hydrogen to carbon ratio.
Benzene is a cyclic compound with a cyclic cloud of delocalized electrons above and below the plane of the rings, due to this, all the c-c bond have the same length. This compound is also stable as a result of its resonance energy (36kcal/mol or 151kJ/mol)
A compound is said to be aromatic if the following conditions are satisfied
A compound is said to be aromatic if the following conditions are satisfied
# The cloud must contain an odd number of pairs of pi electron
# The cloud must contain an odd number of pairs of pi electron
# It must have an interrupted cyclic cloud of pi electron(pi-cloud) above and below the plane of the molecule.
# It must have an interrupted cyclic cloud of pi electron (pi-cloud) above and below the plane of the molecule.
# It must satisfy the hukel rule of (4n + 2)pi electrons.<ref>Bruice, P. Y., Organic Chemistry, p. 595</ref>
# It must satisfy [[w:Hückel's rule|Hückel's rule]] of (4n + 2)pi electrons.<ref>Bruice, P. Y., Organic Chemistry, p. 595</ref>
In conclusion aromaticity is characterized by stability while antiaromaticity is characterized by instability. Aromatic compounds are characterized by substitution reaction such as nitration, alkylation e.t.c, more detailed description of which is accessible through this [http://www.buythesisonline.org link]. They possess double bond but will never undergo addition reaction due to their stability. The scope of aromaticity is beyond this topic given, for clear understanding, one must consult higher materials.
In conclusion, aromaticity is characterized by stability while anti-aromaticity is characterized by instability. Aromatic compounds are characterized by substitution reaction such as nitration, alkylation etc. They possess double bond but will never undergo addition reaction due to their stability. The scope of aromaticity is beyond this topic given, for clear understanding, one must consult higher materials.
==Definition of terms==
==Definition of terms==