posted on 2021-11-05, 02:46authored byMillar, Keith Raymond
A vast volume of literature exists on this subject, the major portion being concerned with nucleophilic aliphatic substitution reactions covered by the general equation:- Y + Alk - X --> Alk - Y + X (SN) where the new bond is formed by co-ordination, and the old one broken by heterolysis, as indicated by the dotted line. There is necessarily and electron transfer from the substituting species Y to the centre of substitution in Alk, and from this centre to the expelled group X; hence Y becomes formally one electronic unit more positive and X one unit more negative.