Number of possible isomer for the complex `[Co(en)_(2)CI_(2)]CI` will be: (em = ethylenediamine)

Options

A. 3
B. 4
C. 2
D. 1

Answer

A

Explanation

Look out for geometrical as well as optical isomerism. Geometrical isomerism arises in octahedral complexes when didentate ligands L-L `[e.g., H_(2)NCH_(2)CH_(2)NH_(2) (en)]` are present in complexes of formula `[MX_(2)(L-L)_(2)]`. Thus, there are two geometrical isomers (cis and trans) of `[CoC1_(2)(en)_(2)]`

In a coordination entity of the type `[MX_(2)(L-L)_(2)]`, only the cis-isomer show optical activity
ltbr The trans form of `[Co(en)_(2)C1_(2)]^(2+)` is optically inactive because it has a plane of symmetry. Thus, total number of steroiromers are `(+)` - cis, `(-)` and trans - form