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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 ...
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.
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 ]
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 ...
In organometallic chemistry, a sandwich compound is a chemical compound featuring a metal bound by haptic, covalent bonds to two arene (ring) ligands. The arenes have the formula C n H n, substituted derivatives (for example C n (CH 3) n) and heterocyclic derivatives (for example BC n H n+1). Because the metal is usually situated between the ...
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 ).
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.
The 18-electron rule is the equivalent of the octet rule in main group chemistry and provides a useful guide for predicting the stability of organometallic compounds. [34] It predicts that organometallic species "in which the sum of the metal valence electrons plus the electrons donated by the ligand groups total 18 are likely to be stable."