`[Fe(CN)_(6)]^(4-)` and `[Fe(H_(2)O)_(6)]^(2+)` are of different colours in dilute solutions why?

Explanation

In both the complexes Fe in `+2` oxidation state with cf configuration This means that it has four unpaired electrons Both `CN^(-)` ion and `H_(2)O` molecules act as ligands occupy different relative positions in the spectrochemical series. They differ in crystal field splitting energy `(Delta_(0))` Quite obviously they absorb radiations corresponding to different wavelenths and frequencies from the visible region of light (VIBGYOR) and the transmitted colours are also different this means that the complexes have different colours in solutions.