AgBr dissolves in the excess of KCN and Na₂S₂O₃ solutions due to the formation of complex ions. The ions are respectively

Reaction of AgCl with KCN is:

$\mathrm{AgCl}+2\mathrm{KCN}\to [\mathrm{Ag}{\left(\mathrm{CN}\right)}_2{]}^{-}+2{\mathrm{K}}^{+}+{\mathrm{Cl}}^{-}$

Reaction of AgCl with Na₂S₂O₃ is:

$\mathrm{AgCl}+2{\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3\to [\mathrm{Ag}{\left({\mathrm{S}}_2{\mathrm{O}}_3\right)}_2{]}^{3-}+{\mathrm{Cl}}^{-}+4{\mathrm{Na}}^{+}$

Therefore, the complex are ${\left[\mathrm{Ag}(\mathrm{CN}{)}_2\right]}^{-}\text{and }{\left[\mathrm{Ag}{\left({\mathrm{S}}_2{\mathrm{O}}_3\right)}_2\right]}^{3-}$.