Why are `Mn^(2+)` compounds more stable than `Fe^(2+)` towards oxidation to their + 3 state ?

Explanation

`Mn^(2+)(3d^(5))` is more stable than `Mn^(3+)(3d^(4))`, because the former has half - filled 3d - subshell. So `Mn^(2+)` is not susceptible to oxidation to `Mn^(3+)` state. On the other hand, `Fe^(3+)(3d^(5))` is more stable than `Fe^(2+)(3d^(6))`, because the former has half - filled 3d - subshell. Hence, `Fe^(2+)` is susceptible to oxidation to `Fe^(3+)`. Therefore, `Mn^(2+)` compounds are more stable than `Fe^(2+)` towards oxidation to their + 3 state.