What are aromatic compounds?
aromatic compounds contain hydrocarbon class, which include a six -member unsaturated carbon circle in which valence electrons are completely delocalized or conjugated. These compounds are stable and abundant in natural and synthetic forms. The simplest of the aromatic compounds is benzene (C6H6), a flammable carcinogen, but industrially important chemicals. The aromatic name is based on the strong aromas of many larger aromatic compounds. Diamonds and graphite, even if they are not considered aromatic compounds, demonstrate delocalized electron sharing at very long atomic distances.
The covalent bond to the carbon-carbon, the basis of organic chemistry, shares two electrons between two adjacent carbon atoms as one binding or four electrons between two carbons in double binding. The conjugated system has a number of alternating individual and double links that can be represented by two or more lewis structures. The conjugation or resonance occurs when P- is availableOrbitals, or D orbitals in larger molecular weight compounds in which the available valence electrons are spreading. Conjugation can occur in linear, branched or cyclic configurations between atoms of carbon, oxygen or nitrogen atoms.
aromaticness occurs when the electrons in the carbon chain are even more delocalized by creating a six-leaf ring with the equivalent of three of the AC individual and double bonds. If benzene treated as a molecule with three double bonds, chemists would expect the double bonds of the molecules to be shorter than the individual bonds, but the lengths of carbon bonds of benzene are the same and prams. Benzene and other aromatic compounds are not subject to adding reactions as alkenes. Alkenes add groups across their double bonds, while aromatic compounds replace the hydrogen atom for the group.
energy released when cyclohexen is hydrogenated onCycling of hydrogen into a double binding is 28.6 kcal per mol. Cyclo -hexadine hydrogenation with two double bonds releases 55.4 kcal/mol or 27.7 kcal per mol H2. Benzene releases 49.8 kcal per pier or 16.6 kcal per mol H2 after complete hydrogenation. Remarkably low value is the measure of the stability of the aromatic structure.
Chemists explain the plater morphology of benzene, the same length of carbon bonds and the low energy of its double bonds by closing the orbitals 2P are distributed in all six carbons. Delocalized pi orbitals are visualized as forming torus above and below the plane of the skeletal skeleton circle. This configuration explains all its features and supports the concept of shared pi orbitals in other conjugated systems.
aromatic compounds often exert pressure of vapor and many gaseous molecules are detectable by human noses. Cinnamon bark, winter and vanilla beans have aromatic compounds that people can feel. Sydiploma work on these or belowThe ranks of compounds are also the basis of artificial aroma.
Some very interesting aromatic compounds consist of polycyclic structures that share one or more sides of a six -member carbon ring with an adjacent carbon circle. Naphtalene (C10H8) has two connected benzene rings; The three rings were connected linearly are called anthracen (C14H10), while six benzene rings in the circle, with a very high level of electron deocization, are called hexhelicen (C26H16). As the number of rings increases, the hydrogen ratio to the carbon decreases, the material becomes more stable, heavier and increases the melting point. As the ratio approaches zero, the compound is basically a different form of carbon. Graphite consists of leaves of delocalized circular structures with hybridized atoms of SP2 carbon and diamonds are hybridized SP3 in three -dimensional interconnected structures similar to cage due to aromaticness.