what are aromatic chemicals

Aromatic compound

Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons",[1] are organic compounds containing one or more aromatic rings. The parent member is benzeneHeteroarenes are closely related, since at least one carbon atom of CH group is replaced by one of the heteroatoms oxygennitrogen, or sulfur. Examples of non-benzene compounds with aromatic properties are furan, a heterocyclic compound with a five-membered ring that includes a single oxygen atom, and pyridine, a heterocyclic compound with a six-membered ring containing one nitrogen atom.

Benzene{\displaystyle {\ce {C6H6}}}, is the least complex aromatic hydrocarbon, and it was the first one named as such. The nature of its bonding was first recognized by August Kekulé in the 19th century. Each carbon atom in the hexagonal cycle has four electrons to share. One goes to the hydrogen atom, and one to each of the two neighboring carbons. This leaves one electron to share with one of the two neighboring carbon atoms, thus creating a double bond with one carbon and leaving a single bond with the other, which is why some representations of the benzene molecule portray it as a hexagon with alternating single and double bonds.

Other depictions of the structure portray the hexagon with a circle inside it, to indicate that the six electrons are floating around in delocalized molecular orbitals the size of the ring itself. This represents the equivalent nature of the six carbon-carbon bonds all of bond order 1.5; the equivalency is explained by resonance forms. The electrons are visualized as floating above and below the ring, with the electromagnetic fields they generate acting to keep the ring flat.

General properties of aromatic hydrocarbons:

    1. They display aromaticity
    2. The carbon-hydrogen ratio is high
    3. They burn with a strong sooty yellow flame because of the high carbon–hydrogen ratio
    4. They undergo electrophilic substitution reactions and nucleophilic aromatic substitutions

The circle symbol for aromaticity was introduced by Sir Robert Robinson and his student James Armit in 1925[2] and popularized starting in 1959 by the Morrison & Boyd textbook on organic chemistry. The proper use of the symbol is debated: some publications use it to any cyclic π system, while others use it only for those π systems that obey Hückel's rule. Jensen[3] argues that, in line with Robinson's original proposal, the use of the circle symbol should be limited to monocyclic 6 π-electron systems. In this way the circle symbol for a six-center six-electron bond can be compared to the Y symbol for a three-center two-electron bond.

source: https://en.wikipedia.org/wiki/Aromatic_compound


United Kingdom
Unit 20, Burrough Court,
Burrough On The Hill,
Melton Mowbray,
Leicestershire,  LE14 2QS
+44 0203 930 0833
Middle East
Dubai South Business Centre
Building A3 - 3rd Floor,
Dubai Logistics City
PO BOX 390667,
Dubai, United Arab Emirates
+971 05250 87972
John Kellys Europe BVB
15li 1058sn
+44 0203 930 0833

4 Trav Dupont
+44 0203 930 0833
Connect with us