explain how coordination compound exhi colour and what will be the colour if yellow region colour wavelength is observed by the coordination compound?

Coordination compounds shows many properties among which,exhibiting colour is one of them.These compounds are of various colours.The reason for showing different colours is that transition elements have incompletely filled d-orbitals due to which there is possibilty of promotion of electrons from lower d-orbital to higher empty d-orbital when light of particular wavelength is absorbed by the compound.
The compound has colour because it absorbs light of certain wavelength from visible part of spectrum and reflects the other wavelength.When white light is absorbed by the coordination compound,a light of certain wavelength is absorbed and reflected or transmitted light is coloured,which is complimentary to that which is absorbed.For ex- the colour will be blue if yellow colour wavelength is observed by the coordination compound,as blue and yellow are complimentary to each other.