Optical Isomerism only occurs in octahedral complexes containing two or more bidentate
ligands.
Optical isomers aka enantiomers are pair of non- superimposable mirror images of each other.
Cis- isomers may also show optical isomerism such as above.
In questions, best to draw optical isomerism with three bidentate.
Trans- isomers can’t as can be superimposed.
Optical isomers can also have three bidentate ligands.
