Complexes exhibit isomerism.Presence of the following ligand is a necessary condition to exhibit linkage isomerism by a complex

${\mathrm{CN}}^{-},{\mathrm{SCN}}^{-},{\mathrm{NO}}_2^{-},{\mathrm{ONO}}^{-},{\mathrm{NC}}^{-},{\mathrm{NCS}}^{-}$are ambidendate ligands. Complexes containing  ambidentate ligands exhibit linkage isomerism.
$\mathrm{Ex}:-{\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5{\mathrm{NO}}_2\right]}^{+2}\mathrm{and}{\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\mathrm{ONO}\right]}^{+2}$