# Why can Bi not achieve its 4+ oxidation state?

Bi can reach its 3+ and 5+ oxidation state. Why not 4+? Can you use the inert pair effect here to explain this?

• Well bismuth is in group 15 so, +4 oxidation is probably rare. I don't think that has anything to with inert pair effect. Group 15 generally shows +3 and +5 states because they give closed-shell species. +4 would result in an unpaired electron i.e. a radical – S R Maiti May 20 at 9:28

The properties of bismuth (IV), which is formed from the reaction of Cl2 with bismuth (III) agree with previously established relationships on the variation in optical transition energies and the unpaired electron density at the s atomic orbital of the ion for the series of isoelectronic ions mercury (I), thallium (II), lead (III), and bismuth (IV) in the $$^2S_{1/2}$$ state.