8.21 How would you account for the following:

(i) Of the d^{4} species, Cr^{2+} is strongly reducing while manganese(III) is strongly oxidising.

Answers (1)
M manish

Cr^{2+}is strongly reducing in nature. It has d^{4} configuration. By losing one electron it gets oxidised to Cr^{3+}(electronic configuration d^{3}) which can be written as t^{3}_{2g} and it is a more stable configuration. On the other hand Mn^{3+} has also d^{4} configuration by accepting one electron it gets reduced and act as strongly oxidising agent(electronic configuration d^{5}). Thus it is extra stable due to half -filled with d-orbital.