Question

Explain how sulphur exists in the +4 oxidation state.

Answer 1

1. Sulphur in the +4 oxidation state occurs when it excites its np-electrons to vacant nd-orbitals (first excited state).
2. This gives sulphur four unpaired electrons to form four bonds.
3. The hybridisation involved is sp³d.
4. The electron distribution is trigonal bipyramidal with one position occupied by a lone pair.
5. Such a state is common for sulphur and other heavier group 16 elements due to their vacant d-orbitals.