Linkage isomers are coordination compounds that have the same composition but differ in the connectivity of the ligand to the metal.
For example, a thiocyanato group could be connected to the metal atom by either the S atom or the N atom.
Typical ligands that give rise to linkage isomers are:
- thiocyanate, SCN⁻ and isothiocyanate, NCS⁻
- selenocyanate, SeCN⁻ and isoselenocyanate, NCSe⁻
- nitrite, NO₂⁻
- sulfite, SO₃²⁻
Two examples of linkage isomers are
-
the violet thiocyanato-κ-S and orange thiocyanato-κ-N isomers [(NH₃)₅Co-SCN]²⁺ and [(NH₃)₅Co-NCS]²⁺
-
the yellow nitrito-κ-N and red nitrito-κ-O isomers [(NH₃)₅Co-NO₂]²⁺ and [(NH₃)₅Co-ONO]²⁺
