Which one of the following is expected to exhibit optical isomerism (en=ethylenediamine)?

Options

A. cis-`[Pt(NH_(3))_(2)CI_(2)]`
B. trans-`[Co(en)_(2)CI_(2)]`
C. trans- `[Pt(NH_(3))_(2)CI_(2)]`
D. cis- `[Co(en)_(2)CI_(2)]^(+)`

Answer

D

Explanation

Square planer complexes (1 and 3) never exhibit optical isomerism as the plane in which complex lies is itself a plane of symmetry. Trans -`[Co(en)_(2)C1_(2)]` is optically inative due to the presence of a plane of symmerty. However, sic-`[Co(en)_(2)C1_(2)]^(+)` is optically active as it possesses no symmetry element such as a plane of symmetry.