Answer:
The colour in coordination
compounds can be explained on the basis of crystal field theory. When a complex
compound is formed the degeneracy of d-orbitals is lost due to the interaction
of ligands.
When light falls
on this coordination compound electrons present in lower d-orbitals absorb a
light corresponding to the energy required for its promotion to higher d-orbital.
As some portion
of light is absorbed from visible region the light that return back looks
coloured. Colour of complex is the complementary of colour absorbed.
e.g. 
absorbs yellow green region and looks
violet.
You need to login to perform this action.
You will be redirected in
3 sec
