Colr of KMnO4

OXYSALTS of some of the transition elements ,e.g.KMnO₄ and K₂Cr₂O₇ are coloured though the central atom does not contain any unpaired electrons . the colour of thees compounds arises due to CHARGE TRANSFER SPECTRUM (colour is associated with the electrons being promoted from one energy level to another , and absorbing or emitting the energy difference between the two levels . thus transfer of an electron from M to L or vice versa results in charge transfer which gives rise to spectra .such spectra are called charge transfer spectra) . Ag⁺ does not contain any unpaired electrons but some of the compounds of silver are coloured which can be explained on the basis of ionic character . when the ionic character of these ionic compounds is less than 20% , then the compound will be coloured.