In octahedral coordination entities like [Co(NH₃)₃(NO₂)₃], if ligands occupy adjacent positions at the corners of an octahedral face, it is the facial (fac) isomer. When they are around the meridian, it is the meridional (mer) isomer.

Geometrical isomerism occurs in complexes of the formula [MX₂(L–L)₂] when didentate ligands like ethane-1,2-diamine (en) are present.

In [MX₂L₂], square planar complexes, the ligands X can be arranged adjacent (cis) or opposite (trans). Such isomerism is not possible in tetrahedral geometry. Octahedral complexes [MX₂L₄] also exhibit similar cis-trans isomerism.

Stereoisomerism in heteroleptic complexes arises from different geometric arrangements of ligands. Examples occur in coordination numbers 4 and 6, such as square planar complexes [MX₂L₂] and octahedral complexes [MX₂L₄].

Isomers are compounds with the same chemical formula but different atom arrangements. Stereoisomers have the same chemical bonds but differ in spatial arrangement, while structural isomers have different bonds.