Class 12 NEET Chemistry Coordination Compounds

A species is coloured when it contains unpaired d-electrons which are capable of undergoing d-d transition on adsorption of light of a particular wavelength.
In TiF62−,Ti4+‌‌:3d0,  colourless
In CoF63−,Co3+‌‌:3d6  coloured
In Cu2Cl2,Cu+‌‌‌‌:3d10  colourless
In NiCl42−,Ni2+‌‌‌:3d8  coloured
Thus TiF62−(3d0) and Cu2Cl2(3d10) with empty and fully filled d-orbitals appear colourless asa they are not capable of undergoing d-d transition