Question

The correct order of stabilities of the following superoxides is

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

As we go down the group, the size of the cation increases. In general, the stability is high when both the ions are of a similar size. $O_2^{-}$ is a large anion and thus it can be stabilized by a large cation, as similar size of ions leads to higher coordination number and thus higher lattice energy. Hence, the stability is in the order $Cs{O}_2>Rb{O}_2>K{O}_2$