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  2. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...

  3. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...

  4. Pyramidal inversion - Wikipedia

    en.wikipedia.org/wiki/Pyramidal_inversion

    Pyramidal inversion in nitrogen and amines is known as nitrogen inversion. [8] It is a rapid oscillation of the nitrogen atom and substituents, the nitrogen "moving" through the plane formed by the substituents (although the substituents also move - in the other direction); [ 9 ] the molecule passing through a planar transition state . [ 10 ]

  5. Fluxional molecule - Wikipedia

    en.wikipedia.org/wiki/Fluxional_molecule

    In chemistry and molecular physics, fluxional (or non-rigid) molecules are molecules that undergo dynamics such that some or all of their atoms interchange between symmetry-equivalent positions. [1] Because virtually all molecules are fluxional in some respects, e.g. bond rotations in most organic compounds , the term fluxional depends on the ...

  6. Talk:Anatomical terms of motion - Wikipedia

    en.wikipedia.org/wiki/Talk:Anatomical_terms_of...

    Could the difference between inversion/eversion and pronation/supination of the foot please be clarified? As far as I can tell, the definitions given in the article are synonymous with each other: Pronation of the foot refers to turning of the sole outwards, so that weight is borne on the medial part of the foot.

  7. Umpolung - Wikipedia

    en.wikipedia.org/wiki/Umpolung

    In organic chemistry, umpolung (German: [ˈʔʊmˌpoːlʊŋ]) or polarity inversion is the chemical modification of a functional group with the aim of the reversal of polarity of that group. [ 1 ] [ 2 ] This modification allows secondary reactions of this functional group that would otherwise not be possible. [ 3 ]

  8. Rotamer - Wikipedia

    en.wikipedia.org/wiki/Rotamer

    The energy difference between gauche and anti is 0.9 kcal/mol associated with the strain energy of the gauche conformer. The anti conformer is, therefore, the most stable (≈ 0 kcal/mol). The three eclipsed conformations with dihedral angles of 0°, 120°, and 240° are transition states between conformers. [6]

  9. Sigmatropic reaction - Wikipedia

    en.wikipedia.org/wiki/Sigmatropic_reaction

    Sigmatropic rearrangements are concisely described by an order term [i,j], which is defined as the migration of a σ-bond adjacent to one or more π systems to a new position (i−1) and (j−1) atoms removed from the original location of the σ-bond. [3]