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  2. Activated complex - Wikipedia

    en.wikipedia.org/wiki/Activated_complex

    In chemistry, an activated complex represents a collection of intermediate structures in a chemical reaction when bonds are breaking and forming. The activated complex is an arrangement of atoms in an arbitrary region near the saddle point of a potential energy surface . [ 1 ]

  3. Reaction mechanism - Wikipedia

    en.wikipedia.org/wiki/Reaction_mechanism

    A chain reaction is an example of a complex mechanism, in which the propagation steps form a closed cycle. In a chain reaction, the intermediate produced in one step generates an intermediate in another step. Intermediates are called chain carriers. Sometimes, the chain carriers are radicals, they can be ions as well.

  4. Ring expansion and contraction - Wikipedia

    en.wikipedia.org/wiki/Ring_expansion_and_contraction

    While it proceeds through an intermediate bicycle the final cyclization and ring opening take place within the same radical reaction. [12] This expansion is useful because it allows the expansion of a beta-ketoester to a large cyclic ketone which can easily be elaborated using either the cyclic ketone or the exocyclic ester.

  5. Reaction intermediate - Wikipedia

    en.wikipedia.org/wiki/Reaction_intermediate

    In chemistry, a reaction intermediate, or intermediate, is a molecular entity arising within the sequence of a stepwise chemical reaction. It is formed as the reaction product of an elementary step, from the reactants and/or preceding intermediates, but is consumed in a later step. It does not appear in the chemical equation for the overall ...

  6. Ring-closing metathesis - Wikipedia

    en.wikipedia.org/wiki/Ring-closing_metathesis

    Ring-closing metathesis (RCM) is a widely used variation of olefin metathesis in organic chemistry for the synthesis of various unsaturated rings via the intramolecular metathesis of two terminal alkenes, which forms the cycloalkene as the E-or Z-isomers and volatile ethylene.

  7. Dissociative substitution - Wikipedia

    en.wikipedia.org/wiki/Dissociative_substitution

    Dissociative pathways are characterized by a rate determining step that involves release of a ligand from the coordination sphere of the metal undergoing substitution. The concentration of the substituting nucleophile has no influence on this rate, and an intermediate of reduced coordination number can be detected.

  8. Reactive intermediate - Wikipedia

    en.wikipedia.org/wiki/Reactive_intermediate

    In chemistry, a reactive intermediate or an 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 can these compounds be isolated and stored, e.g. low temperatures, matrix isolation. When their existence is ...

  9. Chemical bond - Wikipedia

    en.wikipedia.org/wiki/Chemical_bond

    A chemical bond is an attraction between atoms. This attraction may be seen as the result of different behaviors of the outermost or valence electrons of atoms. These behaviors merge into each other seamlessly in various circumstances, so that there is no clear line to be drawn between them.