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Benzene is an organic chemical compound with the molecular formula C 6 H 6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon.
Heteroarenes are aromatic compounds, where at least one methine or vinylene (-C= or -CH=CH-) group is replaced by a heteroatom: oxygen, nitrogen, or sulfur. [3] 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 ...
Hückel's rule can also be applied to molecules containing other atoms such as nitrogen or oxygen. For example pyridine (C 5 H 5 N) has a ring structure similar to benzene, except that one -CH- group is replaced by a nitrogen atom with no hydrogen. There are still six π electrons and the pyridine molecule is also aromatic and known for its ...
One or more of the hydrogen atoms can be replaced with other atoms, for example chlorine or another halogen: this is called a substitution reaction. An example is the conversion of methane to chloroform using a chlorination reaction. Halogenating a hydrocarbon produces something that is not a hydrocarbon. It is a very common and useful process.
Cyclic compounds may or may not exhibit aromaticity; benzene is an example of an aromatic cyclic compound, while cyclohexane is non-aromatic. In organic chemistry, the term aromaticity is used to describe a cyclic (ring-shaped), planar (flat) molecule that exhibits unusual stability as compared to other geometric or connective arrangements of ...
An aromatic π-sextet can be represented by a circle, as in the case of the anthracene molecule (below). Clar's rule states that for a benzenoid polycyclic aromatic hydrocarbon (i.e. one with only hexagonal rings), the resonance structure with the largest number of disjoint aromatic π-sextets is the most important to characterize its chemical ...
The simplest aryl group is phenyl, which is made up of a benzene ring with one of its hydrogen atom replaced by some substituent, and has the molecular formula C 6 H 5 −. Note that a phenyl group is not the same as a benzyl group, the latter consisting of a phenyl group attached to a methyl group and a molecular formula of C 6 H 5 CH 2 −. [2]
In the basic aromatic rings, the lone pair of electrons is not part of the aromatic system and extends in the plane of the ring. This lone pair is responsible for the basicity of these nitrogenous bases, similar to the nitrogen atom in amines. In these compounds, the nitrogen atom is not connected to a hydrogen atom.