10.1 INTRODUCTION:
- Ionic reactions are those in which covalent bonds break heterolytically, and in
which ions are involved as reactants, intermediates, or products.
- Heterolytic bond dissociation (heterolysis): electronically unsymmetrical bond
breaking ⇒ produces ions.
- Heterogenic bond formation: electronically unsymmetrical bond making.
- Homolytic bond dissociation (homolysis): electronically symmetrical bond
breaking ⇒ produces radicals (free radicals).
- Hemogenic bond formation: electronically symmetrical bond making.
A B homolysis A + B
Radicals
i) Single-barbed arrows are used for the movement of a single electron.
10.1A PRODUCTION OF RADICALS
- Energy must be supplied by heating or by irradiation with light to cause
homolysis of covalent bonds.
- Homolysis of peroxides:
R O O R heat^2 R O
Dialkyl peroxide Alkxoyl radicals
2) Homolysis of halogen molecules: heating or irradiation with light of a wave
length that can be absorbed by the halogen molecules.
XX heathom orolysis light 2 X
10.1B REACTIONS OF RADICALS:
