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  2. 18-electron rule - Wikipedia

    en.wikipedia.org/wiki/18-electron_rule

    The 18-electron rule is a chemical rule of thumb used primarily for predicting and rationalizing formulas for stable transition metal complexes, especially organometallic compounds. [1] The rule is based on the fact that the valence orbitals in the electron configuration of transition metals consist of five ( n −1)d orbitals, one n s orbital ...

  3. Tolman's rule - Wikipedia

    en.wikipedia.org/wiki/Tolman's_rule

    Tolman's rule states that, in a certain chemical reaction, the steps involve exclusively intermediates of 18- and 16 electron configuration. The rule is an extension of the 18-electron rule . This rule was proposed by American chemist Chadwick A. Tolman . [ 1 ]

  4. Electron counting - Wikipedia

    en.wikipedia.org/wiki/Electron_counting

    Many rules in chemistry rely on electron-counting: Octet rule is used with Lewis structures for main group elements, especially the lighter ones such as carbon, nitrogen, and oxygen, 18-electron rule [2] in inorganic chemistry and organometallic chemistry of transition metals, Hückel's rule for the π-electrons of aromatic compounds,

  5. Hexaamminecobalt(III) chloride - Wikipedia

    en.wikipedia.org/wiki/Hexaamminecobalt(III)_chloride

    The cation obeys the 18-electron rule and is considered to be a classic example of an exchange inert metal complex. As a manifestation of its inertness, [Co(NH 3 ) 6 ]Cl 3 can be recrystallized unchanged from concentrated hydrochloric acid : the NH 3 is so tightly bound to the Co(III) centers that it does not dissociate to allow its protonation ...

  6. Polyhedral skeletal electron pair theory - Wikipedia

    en.wikipedia.org/wiki/Polyhedral_skeletal...

    One consequence of their increased size, these clusters often contain atoms at their centers. A prominent example is [Fe 6 C(CO) 16] 2-. In such cases, the rules of electron counting assume that the interstitial atom contributes all valence electrons to cluster bonding. In this way, [Fe 6 C(CO) 16] 2-is equivalent to [Fe 6 (CO) 16] 6-or [Fe 6 ...

  7. Chadwick A. Tolman - Wikipedia

    en.wikipedia.org/wiki/Chadwick_A._Tolman

    In 1972, he proposed the 16 and 18 electron rule, extending Irving Langmuir's 18-Electron rule to include the many examples of stable 16 electron square planar d 8 complexes. [4] Later work focused on the activation of C-H bonds by transition metal complexes [ 5 ] [ 6 ] and free radical oxidation of cyclohexane for the production of adipic acid ...

  8. Chemical reaction - Wikipedia

    en.wikipedia.org/wiki/Chemical_reaction

    The number of ligands that react with a central metal atom can be found using the 18-electron rule, saying that the valence shells of a transition metal will collectively accommodate 18 electrons, whereas the symmetry of the resulting complex can be predicted with the crystal field theory and ligand field theory.

  9. Wilkinson's catalyst - Wikipedia

    en.wikipedia.org/wiki/Wilkinson's_catalyst

    From the perspective of the 18-electron rule, the four ligands each provides two electrons, for a total of 16-electrons. As such the compound is coordinatively unsaturated , i.e. susceptible to binding substrates (alkenes and H 2 ).