Earlier we looked at cis- and trans-isomers in square planar platinum complexes. Other transition metal complexes display cis-trans isomerism. Octahedral complexes can also have two particular ligands adjacent to each other or on opposite sides of the metal atom. For example, the cation [(NH3)4CoCl2]+ has a cis-isomer and a trans-isomer.
Figure SC17. Cis and trans-isomers of an octahedral cobalt compound.