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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. Alkaline earth octacarbonyl complex - Wikipedia

    en.wikipedia.org/wiki/Alkaline_earth_octa...

    Quantum chemical calculations using density functional theory confirm that Ca, Sr, and Ba can indeed utilize their (n-1)d in bonding to satisfy the 18-electron rule. [1] [6] These computational results support the hypothesis that alkaline earth octacarbonyl complexes follow the 18-electron rule and are comparable to carbonyl transition metal ...

  4. 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 ]

  5. Half sandwich compound - Wikipedia

    en.wikipedia.org/wiki/Half_sandwich_compound

    In organometallic chemistry, (η 6-C 6 H 6) piano stool compounds are half-sandwich compounds with (η 6-C 6 H 6)ML 3 structure (M = Cr, Mo, W, Mn(I), Re(I) and L = typically CO). (η 6-C 6 H 6) piano stool complexes are stable 18-electron coordination compounds with a variety of chemical and material applications.

  6. 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 ).

  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. Pauli exclusion principle - Wikipedia

    en.wikipedia.org/wiki/Pauli_exclusion_principle

    In the case of electrons in atoms, the exclusion principle can be stated as follows: in a poly-electron atom it is impossible for any two electrons to have the same two values of all four of their quantum numbers, which are: n, the principal quantum number; ℓ, the azimuthal quantum number; m ℓ, the magnetic quantum number; and m s, the spin ...

  9. Chemical reaction - Wikipedia

    en.wikipedia.org/wiki/Chemical_reaction

    Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reactants or reagents.