JAYANT ARORA
Last Activity: 11 Years ago
The color in KMnO4 arises from an electronic transition, but it is actually not a d-d transition, since the Mn in this compoundhas no d electrons. It arises from a charge transfer reaction within the molecule, in which photons promote an electron from the highest energy molecular orbital in one of the Mn- O bonds to an empty d orbital on the manganese. This promotion is equivalent to the energy of a yellow photon, so yellow light is absorbed leaving us to see pink , the complementary color.