Why is CuI2 unstable?

1 Answer
Feb 26, 2018

#CuI_2# will have a redox reaction

Explanation:

If we bring together #Cu^(2+)# and #I^-# ions the copper(II) will be reduced to copper(I), while part of the iodide will be oxidized to iodine.
Copper(I)iodide is badly soluable:

#2Cu^(2+)(aq)+4I^-(aq) -> 2CuI(s)+I_2(aq)#

The partial reactions being:
#2Cu^(2+)(aq)+2e^(-) ->2Cu^+(aq)# = reduction
#2I^(-)(aq) ->I_2(aq)+2e^-# = oxidation
#2Cu^+(aq) +2I^(-)(aq)->2CuI(s)# = precipitation