In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist between two different elements: for example, in a carbonyl group between a carbon atom and an oxygen atom. Other common double bonds are found in azo compounds (N=N), imines (C=N), and sulfoxides (S=O). In a skeletal formula, a double bond is drawn as two parallel lines (=) between the two connected atoms; typographically, the equals sign is used for this.[1][2] Double bonds were introduced in chemical notation by Russian chemist Alexander Butlerov.[citation needed]
Double bonds involving carbon are stronger and shorter than single bonds. The bond order is two. Double bonds are also electron-rich, which makes them potentially more reactive in the presence of a strong electron acceptor (as in addition reactions of the halogens).
- Chemical compounds with double bonds
-
Ethylene Carbon-carbon double bond -
Acetone Carbon-oxygen double bond -
Dimethyl sulfoxide Sulfur-oxygen double bond -
Diazene Nitrogen-nitrogen double bond
- ^ March, Jerry, 1929-1997. (1985). Advanced organic chemistry : reactions, mechanisms, and structure (3rd ed.). New York: Wiley. ISBN 0-471-88841-9. OCLC 10998226. Archived from the original on 2019-12-10. Retrieved 2020-12-12.
{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link) - ^ McMurry, John. Organic chemistry (Ninth ed.). Boston, MA, USA. ISBN 978-1-305-08048-5. OCLC 907259297. Archived from the original on 2024-04-04. Retrieved 2020-12-12.