Define Linkage Isomerism

Linkage isomerism occurs with ambidentate ligands. These ligands are capable of coordinating in more than one way. The best-known cases involve the monodentate ligands SCN-/NCS- and NO2/ONO

For example

[Co(NH3)5ONO]Cl2 the nitrito isomer – red colour

pentaamminenitritocobalt(III) chloride – O attached

[Co(NH3)5 NO2]Cl2 the nitro isomer – yellow colour

pentaamminenitrocobalt(III) chloride – N attached