[Co(C₂O₄)(NH₃)₂Cl₂]^-
Three geometric isomers are possible for this ion. In the first, each ammonia moelcule is trans to a chloride and and each chloride is trans to an ammonia molecule. This isomer has a nonsuperimposable mirror image (enantiomer), giving the first two models shown below. In the second geometric isomer, the ammonia groups are trans and the chloride groups are cis. Last, in the third geometric isomer, the chloride groups are trans and the ammonia groups are cis.