Heterolytic Fission (DP IB Chemistry)

Heterolytic Fission

Heterolytic fission

• Heterolytic fission is breaking a covalent bond in such a way that the more electronegative atom takes both the electrons from the bond to form a negative ion and leaves behind a positive ion

Diagram to show the process of heterolytic fission

Heterolytic fission forms a positive ion and a negative ion

• In heterolytic fission, a double-headed arrow is used to show the movement of a pair of electrons

• The resulting negative ion is an electron-rich species that can donate a pair of electrons

  • This makes the negative ion a nucleophile

• The resulting positive ion is an electron-deficient species that can accept a pair of electrons

  • This makes the positive ion an electrophile

Heterolytic fission mechanism

• The opposite reaction to heterolytic fission occurs when a nucleophile donates a pair of electrons to the electrophile forming a coordination bond

Reaction between a nucleophile and an electrophile forming a coordination bond

A nucleophile ‘loves’ a positive charge and an electrophile ‘loves’ a negative charge