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