Optical Isomers
cis -[Co(NH3)4Cl2]+ no optical isomers
trans-[Co(NH3)4Cl2]+ no optical isomers
cis-[Co(en)2Cl2]+ optical isomers
trans-[Co(en)2Cl2]+ no optical isomers
[Co(en)Cl4]- no optical isomers
[Co(en)3]2+ optical isomers
[Cu(en)Cl2] no optical isomers
(because square planar complex can be flipped to superimpose mirror image)
Tetrahedral can have optical isomers if all four ligands are different.