1. The problem statement, all variables and given/known data A solution consist of Co+2 and Ni+2 ion in which excess KCN is added and in the resulting solution alkaline Br2 was added. The solution finally consist of which species? 3. The attempt at a solution I guess some complex would be formed but how to exactly find out the complex? I don't have any idea as this does not involve any equations or mathematical approach. Any ideas?