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Cycloalkanes and aromatic compounds can be treated as the main parent chain of the compound, in which case the positions of substituents are numbered around the ring structure. For example, the three isomers of xylene CH 3 C 6 H 4 CH 3 , commonly the ortho- , meta- , and para- forms, are 1,2-dimethylbenzene, 1,3-dimethylbenzene, and 1,4 ...
The main purpose of chemical nomenclature is to disambiguate the spoken or written names of chemical compounds: each name should refer to one compound. Secondarily, each compound should have only one name, although in some cases some alternative names are accepted. Preferably, the name should also represent the structure or chemistry of a compound.
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 ...
The Geneva Nomenclature of 1892 was created as a result of many other meetings in the past, the first of which was established in 1860 by August Kekulé. Another entity called the International Association of Chemical Societies (IACS) existed, and on 1911, gave vital propositions the new one should address: [ 2 ]
This procedure, often known as the sequence rules, is the heart of the CIP system. The overview in this section omits some rules that are needed only in rare cases. Compare the atomic number (Z) of the atoms directly attached to the stereocenter; the group having the atom of higher atomic number Z receives higher priority (i.e. number 1).
[6] [7] It was the German chemist Karl Gräbe who, in 1869, first used the prefixes ortho-, meta-, para- to denote specific relative locations of the substituents on a disubstituted aromatic ring (namely naphthalene). [8] In 1870, the German chemist Viktor Meyer first applied Gräbe's nomenclature to benzene. [9]
These rules were the beginning of international cooperation for organic chemistry nomenclature. [1] They were decided upon by a group of 34 of leading chemists from 9 different European nations. Their goal was to provide rules for the naming of aliphatic compounds, some of which are still in place today such as the longest chain provides the ...
Two different resonance forms of benzene (top) combine to produce an average structure (bottom). In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone.