Which is diamagnetic?

• A

  $\left[\mathrm{Cp}\left(\mathrm{F}_6\right)\right]^{3-}$
• Correct answer
  B

  $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
• C

  $\left[\mathrm{NiCl}_4\right]^{2-}$
• D

  $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$

Solution

$\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ is dimagnetic

Hence, the correct answer is option: 'B'.