Oxidation Number And Oxidation States

Concept: Oxidation state is usually an integer, but in some species (like mixed valence compounds), average oxidation state may be fractional.

Step 1: Check S O (tetrathionate ion):
Let oxidation state of S = x

Step 2: Interpretation:
This fractional value indicates different sulfur atoms have different oxidation states. Conclusion:
Hence, non-integer oxidation state exists.