The structural formula of a chemical compound is a graphical representation of the molecular structure showing how the atoms are arranged. A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. The chemical bonding within the molecule is also shown, either explicitly or implicitly. A chemical bond is the physical process responsible for the attractive interactions between Atoms and Molecules and which confers stability to diatomic and polyatomic There are three common representations used in publications, condensed, Lewis type and line-angle formulæ. Lewis structures, also called Lewis-dot diagrams are diagrams that show the bonding between Atoms of a There are also several formats used for structural representation in chemical databases, such as SMILES, InChI and CML. A chemical database is a Database specifically designed to store chemical information. The IUPAC International Chemical Identifier ( InChI, pronounced "INchee" is a textual Identifier for Chemical substances designed to provide a CML ( C hemical M arkup L anguage is a new approach to managing Molecular information using tools such as XML and Java
Unlike molecular formulae or chemical names, structural formulae provide a very powerful representation of the molecular structure. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general 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. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called In Chemistry, chemical synthesis is purposeful execution of Chemical reactions in order to get a product, or several products
Many chemical compounds exist in different isomeric forms which have different structures yet the same overall chemical formula. Isobutane, also known as methylpropane or 2-methylpropane, is an Alkane, Isomeric with Butane. This article is about the chemical concept For "isomerism" of atomic nuclei see Nuclear isomer. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes A structural formula indicates the arrangements of atoms in a way that a chemical formula cannot. For example, butane, which has the molecular formula C4H10. Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3 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). Isobutane, also known as methylpropane or 2-methylpropane, is an Alkane, Isomeric with Butane. The skeletal formula of an Organic compound is a shorthand representation of its molecular structure. Their structural formulæ are shown at right:
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Common types of structural formula
There are three main types of structural formula in widespread use in the chemical literature. [1]
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 (CH3CH2OH). Strychnine (ˈstrɪkniːn (British US /-naɪn/ or /-nɪn/ (US
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). The skeletal formula of an Organic compound is a shorthand representation of its molecular structure. An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. The skeletal formula of an Organic compound is a shorthand representation of its molecular structure. 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. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general 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. The term chiral (pronounced /ˈkaɪɹ(əl̩/ is used to describe an object that is non- superimposable on its mirror image
References
- ^ Wade, L. G. Organic Chemistry, 4th ed. , p 17-20, Prentic Hall, Upper Saddle River, New Jersey, 1999. [ISBN 0-13-922741-5].
External links
See also
- The Chemistry WikiProject's style guidelines for structural formulae.
- The Chemistry WikiProject structure drawing workgroup, for discussing how structures are represented on Wikipedia.
Dictionary
structural formula
-noun
- (chemistry) Any of various diagrammatic representations of the structure of a molecule that shows how its atoms are linked to each other, with what type of bonds, and the presence of any charges
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