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

Explanation

Electronic configuration of `Mn^(2+)` is `3d^(5)` which is half filled and hence stable. Therefore, 3rd ionizatio enthalpy is very high, i.e., 3rd electron cannot be lost easily. In case of `Fe^(2+)` , electronic configuration is `3d^(6)` . Hence, it can lose one electron easily to give the stable configuration `3d^(5)`