cis −[Cr(ox)2Cl2]3−⟶ can show optical isomerism (no POS & COS) [Co(en)3]3+⟶ can show (no POS & COS) cis −[Pt(en)2Cl2]2+⟶ can show (no POS & COS) cis −[Co(en)2Cl2]+⟶ can show (no POS & COS) trans −[Pt(en)2Cl2]2+⟶ can't show (contains POS & COS) trans −[Cr(ox)2Cl2]3−⟶ can't show (contains POS & COS)