u r right , tushar.
Any compound having more than 20% covalent character is coloured and Ag+ ions polarize the halide ions. thus , The polarisability of ions increase wid size , which gives rise to deeper colours as we go down the group.
Another one -- down the halogen group , Silver halides form deeper coloured compounds . Why?????
NOT SURE
Ag + ion is small and highly polarizing
Cl - is small in size where as I- is large and highly polarizable. This leads to some covalent character in AgI.
u r right , tushar.
Any compound having more than 20% covalent character is coloured and Ag+ ions polarize the halide ions. thus , The polarisability of ions increase wid size , which gives rise to deeper colours as we go down the group.