Which of the following does not show optical isomerism - (en = Ethylenediamine)

Which of the following does not show optical isomerism - (en = Ethylenediamine)
  1. $\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$
  2. $\left[\mathrm{Co}(\mathrm{en})_2 \mathrm{Cl}_2\right]^{+}$
  3. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]^{-}$
  4. $\left[\mathrm{Co}(\mathrm{en}) \mathrm{Cl}_2\left(\mathrm{NH}_3\right)_2\right]^{+}$

Solution

As complexes of the type $\left[\mathrm{MA}_3 \mathrm{~B}_3\right]$ can show geometrical isomerism knows as facmer isomerism and not optical isomerism. So here $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]^0$ can not show optical isomerism.

Asked in: NEET 2009 (Mains)

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