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  2. Clar's rule - Wikipedia

    en.wikipedia.org/wiki/Clar's_rule

    In organic and physical organic chemistry, Clar's rule is an empirical rule that relates the chemical stability of a molecule to its aromaticity.It was introduced in 1972 by the Austrian organic chemist Erich Clar in his book The Aromatic Sextet.

  3. Topological index - Wikipedia

    en.wikipedia.org/wiki/Topological_index

    In the fields of chemical graph theory, molecular topology, and mathematical chemistry, a topological index, also known as a connectivity index, is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound. [1]

  4. SMILES arbitrary target specification - Wikipedia

    en.wikipedia.org/wiki/Smiles_arbitrary_target...

    RECAP [9] (Retrosynthetic Combinatorial Analysis Procedure) uses SMARTS to define bond types. RECAP is a molecule editor which generates fragments of structures by breaking bonds of defined types and the original link points in these are specified using isotopic labels. Searching databases of biologically active compounds for occurrences of ...

  5. Lewis structure - Wikipedia

    en.wikipedia.org/wiki/Lewis_structure

    Each bond consists of a pair of electrons, so if t is the total number of electrons to be placed and n is the number of single bonds just drawn, t−2n electrons remain to be placed. These are temporarily drawn as dots, one per electron, to a maximum of eight per atom (two in the case of hydrogen), minus two for each bond.

  6. Antarafacial and suprafacial - Wikipedia

    en.wikipedia.org/wiki/Antarafacial_and_suprafacial

    For a σ bond, it corresponds to involvement of one "interior" lobe and one "exterior" lobe of the bond. The relationship is suprafacial when the same face of the π system or isolated orbital are involved in the process (think syn). For a σ bond, it corresponds to involvement of two "interior" lobes or two "exterior" lobes of the bond.

  7. Cross-coupling reaction - Wikipedia

    en.wikipedia.org/wiki/Cross-coupling_reaction

    In organic chemistry, a cross-coupling reaction is a reaction where two different fragments are joined. Cross-couplings are a subset of the more general coupling reactions. Often cross-coupling reactions require metal catalyst

  8. Bridging ligand - Wikipedia

    en.wikipedia.org/wiki/Bridging_ligand

    For doubly bridging (μ 2-) ligands, two limiting representation are 4-electron and 2-electron bonding interactions. These cases are illustrated in main group chemistry by [Me 2 Al(μ 2-Cl)] 2 and [Me 2 Al(μ 2-Me)] 2. Complicating this analysis is the possibility of metal–metal bonding.

  9. Terminal alkene - Wikipedia

    en.wikipedia.org/wiki/Terminal_alkene

    The double bond of an alpha olefin is between the #1 and #2 (IUPAC) or α and β (common) carbon atoms. In organic chemistry , terminal alkenes ( alpha-olefins , α-olefins , or 1-alkenes ) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula C x H 2 x , distinguished by having a double bond at the ...