Structural formula

Structural Formula

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Structural formula

The structural formula of a chemical compound

Chemical compound

A chemical compound is a Chemical substance consisting of two or more different chemical element Chemical bond together in a fixed mass ratio that can be split into simpler substances....
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

Lewis structure

Lewis structures, also called Lewis-dot diagrams, Electron-dot diagrams or Electron-dot structures, are diagrams that show the chemical bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule....
and line-angle formulæ. There are also several formats used for structural representation in chemical database

Chemical database

A chemical database is a database specifically designed to store cheminformatics. Most chemical databases store information on stable molecules....
s, such as SMILES, InChI and CML

Chemical Markup Language

CML is an approach to managing molecular information using tools such as XML and Java platform. It was the first domain specific implementation based strictly on XML, the most robust and widely used system for precise information management in many areas....
.

Unlike molecular formulae or chemical names, structural formulas provide a representation of the molecular structure.

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Encyclopedia

The structural formula of a chemical compound

Chemical compound

Lewis structure

Chemical database

A chemical database is a database specifically designed to store cheminformatics. Most chemical databases store information on stable molecules....
s, such as SMILES, InChI and CML

Chemical Markup Language

Chemical reaction

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 reactants....
or synthesis

Chemical synthesis

In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product , or several products. This happens by physics and chemical manipulations usually involving one or more reactions....
using structural formulas rather than by chemical names, because the structural formulas allow the chemist to visualize the molecules and the changes that occur.

Many chemical compounds exist in different isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulae. Isomers do not necessarily share similar properties unless they also have the same functional groups....
ic forms which have different structures yet the same overall chemical formula

Chemical formula

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 in chemical reactions....
. A structural formula indicates the arrangements of atoms in a way that a chemical formula cannot.

Text formulas

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, it remains a convenient way to represent simple structures

CH₃–CH₂–OH or CH₃CH₂OH

Lewis structures

Lewis structure

Lewis structures, also called Lewis-dot diagrams, Electron-dot diagrams or Electron-dot structures, are diagrams that show the chemical bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule....
s are flat graphical formulas that show the atom connectivity, but lack information about the three-dimensional structure of molecules. This notation is mostly used for small linear molecules.

Three-dimensional

Several methods exist to picture the the three-dimensional arrangement of atoms in a chiral

Chirality (chemistry)

The term chiral is used to describe an object that is non-Superposition on its mirror image.Human hands are perhaps the most universally recognized example of chirality: The left hand is a non-superposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands...
molecules.

Fischer projection

The Fischer projection

Fischer projection

The Fischer projection, devised by Hermann Emil Fischer in 1891, is a two-dimensional representation of a Three-dimensional space organic molecule by projection....
is mostly used for linear monosaccharides. The vertical backbone is assumed to form a bridge-like structure on the paper plane with the substituents sticking up:

Newman projection

The Newman projection

Newman projection

A Newman projection, useful in alkane stereochemistry, visualizes chemical conformations of a carbon-carbon chemical bond from front to back, with the front carbon represented by a dot and the back carbon as a circle ....
and the Sawhorse projection are used to depict the stereochemistry at two connected carbon atoms:

Haworth projection

The Haworth projection

Haworth projection

A Haworth projection is a common way of representing the cyclic Structural formula of monosaccharides with a simple three-dimensional perspective....
is used for cyclic sugar

Sugar

Sugar is a class of edible crystalline substances, mainly sucrose, lactose, and fructose. Human taste buds interpret its flavor as sweet. Sugar as a basic food carbohydrate primarily comes from sugar cane and from sugar beet, but also appears in fruit, honey, sorghum, sugar maple , and in many other sources....
s:

Skeletal formulas

Skeletal formula

The skeletal formula of an organic compound is a shorthand representation of its molecular geometry. Skeletal formulae are ubiquitous in organic chemistry because they show complicated structures clearly and they are quick and simple to draw....
s are the standard notation for more complex organic molecules. Carbon (C) atoms are represented by the vertices

Vertex (geometry)

In geometry, a vertex is a special kind of point which describes the corners or intersections of geometric shapes. Vertices are commonly used in computer graphics to define the corners of surfaces in 3d models, where each such point is given as a vector....
(corners) and termini of line segments that are not marked with an atomic symbol. Each carbon atom is in turn assumed to bear enough hydrogen atoms to give the carbon atom four bonds. Hydrogen atoms on atoms other than carbon must be written explicitly.

Chirality in skeletal formulas is indicated by the Natta projection

Natta projection

The Natta projection is a way to depict molecules with complete stereochemistry in two dimensions in a skeletal formula. This concept is named after Giulio Natta....
method. Solid or dashed wedged bonds represent bonds pointing above-the-plane or below-the-plane of the paper, respectively.

Structural formula

Text formulas

Lewis structures

Three-dimensional

Fischer projection

Newman projection

Haworth projection

Skeletal formulas

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