Which complex shows optical isomerism?
Optical isomerism occurs in chiral complexes. [Co(en)3]3+ (octahedral, with 3 bidentate en ligands) lacks a plane of symmetry, forming non-superimposable mirror images (d and l).
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Isomerism - Optical Isomerism and Linkage Ionisation Solvate