In high spin octahedral d5 complexes like [Mn(H2O)6]2+, Mn2+ ion has five unpaired electrons which are filled parallelly in all the t2g and eg orbitals. Since any d-d transition involves reversal of spins, therefore, d-d transitions are spin forbidden. The d-d transitions are also Laporte forbidden because of the presence of centre of symmetry. Thus, Mn2+ (aq) ion gives light pink colour.
Related Questions
Why is Ti(H2O)6 3+ violet in colour ?
Why is KMnO4 Purple in Colour ?
What is the difference between dd transition and charge transfer transition ?
