Which among following complexes is a neutral complex?

Which among following complexes is a neutral complex?
  1. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_5\right] \mathrm{I}_3$
  2. $\left[\mathrm{Co}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$
  3. $\mathrm{Na}\left[\mathrm{Co}\left(\mathrm{NO}_2\right)_6\right]$
  4. $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_3(\mathrm{NCS})\right] \mathrm{Cl}_2$

Solution

The complexes in which the coordination sphere does not carry any charge are called neutral complexes. $\left[\mathrm{Co}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$ is a neutral complex. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_5\right] \mathrm{I}_3$ and $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_3\left(\mathrm{NCS}^2\right)\right] \mathrm{Cl}_2$ are cationic complexes whereas $\mathrm{Na}\left[\mathrm{Co}\left(\mathrm{NO}_2\right)_6\right]$ is an anionic complex.

Asked in: MHT CET 2023 (11 May Shift 1)

Practice more Coordination Compounds questions on Aicharya