Question

Account for the following:

Sulphur exhibits tendency for catenation but oxygen does not.

Explain why:

Sulphur exhibits tendency for catenation but oxygen does not.

Answer 1

1. Oxygen is small in size and has high electronegativity, causing strong repulsion between lone pairs on adjacent oxygen atoms, reducing O-O bond stability.
2. Sulphur atoms are larger with lower electronegativity, allowing S-S bonds to be stronger, and less repulsion occurs between lone pairs.
3. Sulphur has vacant d-orbitals, facilitating bonding and formation of long chains, unlike oxygen, which lacks d-orbitals.
4. Hence, sulphur shows a greater tendency for catenation, forming chains and rings, while oxygen mainly forms only small units like peroxides.

Answer 2

This is because of higher S-S bond energy 213 kJ/mol as compared to O-O bond energy 138 kJ/mol.