Everything about The Structural Formula totally explained
The
structural formula of a
chemical compound is a graphical representation of the molecular structure showing how the atoms are arranged. The
chemical bonding within the molecule is also shown, either explicitly or implicitly. There are three common representations used in publications, condensed,
Lewis type and line-angle formulæ. There are also several formats used for structural representation in
chemical databases, such as
SMILES,
InChI and
CML.
Unlike
molecular formulae or
chemical names, structural formulae provide a very powerful representation of the molecular structure. Chemists nearly always describe a
chemical reaction or
synthesis using structural formulæ rather than chemical names, because the structural formulæ allow the chemist to visualize the changes that occur.
Many chemical compounds exist in different
isomeric forms which have different structures yet the same overall
chemical formula. A structural formula indicates the arrangements of atoms in a way that a chemical formula cannot. For example,
butane, which has the molecular formula C
4H
10. The four carbons may be arranged in a linear pattern, or in a branched, "T" pattern. The first arrangement is known as
orthobutane or
n-butane, while the second is
isobutane (For further simplification the
skeletal formula is used). Their structural formulæ are shown at right:
Common types of structural formula
There are three main types of structural formula in widespread use in the chemical literature.
Condensed formulae
In early organic chemistry publications, where use of graphics was severely limited, a text-based system arose to describe organic structures in a line of text. Although this system tends to break down with complex cyclic compounds such as
strychnine, it remains a convenient way to represent simple structures such as
ethanol (CH
3CH
2OH).
Skeletal formulae
For
organic compounds,
line drawings of structural formula are assumed to have carbon atoms at the vertices and termini of all line segments not marked with the atomic symbol of an element (other than carbon). Each carbon atom is in turn assumed to bear enough hydrogen atoms to give the carbon atom four bonds. Equivalent full and abbreviated forms are shown in the adjacent figures.
A chemical structure can be precisely, uniquely and unambiguously described using
IUPAC nomenclature. In the case of isobutane, the IUPAC systematic name is methylpropane.
Multiple planes
When substituents of a molecule exist in different
planes, their position can be described using solid and dotted wedges, with the former showing a substituent coming out of the plane, and the latter going into it. This system is useful in describing differences between
chiral molecules.
Further Information
Get more info on 'Structural Formula'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://structural_formula.totallyexplained.com">Structural formula Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
