In chemistry a reactive intermediate is a short-lived high energy highly reactive molecule. When generated in a chemical reaction it will quickly convert into a more stable molecule. Only in exceptional cases these compounds can be isolated and stored. Reactive intermediates help explain how a chemical reaction takes place. Chemistry (in Greek: χημεία) is the science of matter and its interactions with energy and itself (see physics, biology). ... In science, a molecule is the smallest particle of a pure chemical substance that still retains its chemical composition and properties. ... A chemical reaction is a process involving one, two or more substances (called reactants), characterized by a chemical change and yielding one or more product(s) which are different from the reactants. ... A chemical reaction is a process involving one, two or more substances (called reactants), characterized by a chemical change and yielding one or more product(s) which are different from the reactants. ...

Most chemical reactions takes more than one "step" to complete, and an reactive intermediate is an unstable product that only exists in one of the intermediate steps. It differs from the reactants and products in the way that it cannot be isolated, and is thus not directly observable. An example would be

A + 2B → C + D + E,

broken down to steps:

A + B → C + X

X → D + Y

B + Y → E.

Here X and Y are intermediates.

The main carbon reactive intermediates.

based on carbon General Name, Symbol, Number Carbon, C, 6 Chemical series Nonmetals Group, Period, Block 14 (IVA), 2, p Density, Hardness 2267 kg/m3 0. ...

• carbocations
• carbanions
• free radicals
• carbenes

A carbocation is an ion with a positively-charged carbon atom. ... A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons). ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... In chemistry a carbene is a short-lived and highly reactive organic molecule with a divalent carbon atom with only 6 valence electrons and the general formula: R1R2C:. The carbon atom is sp2 hybridised with a empty p-orbital extending above and below a plane containing R1 and R2 and...

common features

• low concentration with respect to reaction substrate and final reaction product
• with the exception of carbanions, these intermediates do not obey the lewis octet rule hence the high reactivity
• often generated on chemical decomposition of a chemical compound
• it is often possible to prove the existence of this species by spectroscopic means
• cage effects have to be taken into account
• often stabilisation by conjugation or resonance
• often difficult to distinguist from a transition state
• prove existence by means of chemical trapping

Concentration is a very common concept used in chemistry and related fields. ... The octet rule is a simple chemical theory that states that atoms tend to combine in such a way that they have eight electrons in their valence shells, similar to the electronic configuration of a noble gas. ... chemical decomposition is the gradual fragmentation of a chemical compound into smaller molecules. ... A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. ... Spectroscopy is the study of spectra, that is, the dependence of a physical quantity to frequency. ... Cage Effect (chemistry) The cage effect in chemistry describes how properties of a molecule are affected by its surrounding. ... A chemically conjugated system, is a system of atoms covalently bonded with alternating single and double bonds (e. ... Resonance structures are diagrammatic tools in organic chemistry to symbolize resonant bonds between atoms in molecules. ... A collision between reactant molecules may or may not result in a successful reaction. ... in chemistry, a chemical trap is a chemical compound that is used to detect a certain molecule when the concentration of this molecule is very small and below detection limit the molecule is very reactive and it not possible to isolate or detect it by spectroscopic means the molecule is...

The other reactive intermediates.

• nitrenes
• carbyne
• carbenoid
• arynes

In chemistry, a nitrene (R-N:) is the nitrogen analogue of a (carbon carbene). ... In chemistry A carbyne is a monovalent carbon radical species. ... In chemistry a carbenoid is a reactive intermediate that shares reaction characteristics with a carbene. ... In chemistry, an aryne is an uncharged reactive intermediate derived from an aromatic system by removal of two ortho substituents, leaving two orbitals with two electrons distributed between them. ...

References

• Carey, Francis A.; Sundberg, Richard J.; (1984). Advanced Organic Chemistry Part A Structure and Mechanisms (2nd ed.). New York N.Y.: Plenum Press. ISBN 0-306-41198-9.
• March Jerry; (1885). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc. ISBN 0-471-85472-7
• Gilchrist T.C.;Rees C.W.; (1969) carbenes, nitrenes and arynes. Nelson. London.