Question

The diamagnetic species is :

• A. [Ni(CN)$_4$]$^{2-}$
• B. [NiCl$_4$]$^{2-}$
• C. [Fe(CN)$_6$]$^{3-}$
• D. [CoF$_6$]$^{3-}$

Hint:

When analyzing the magnetic property of coordination compounds, check the electron pairing in the metal's d-orbitals.

Answer 1

The Correct Option is A

In this case, [Ni(CN)$_4$]$^{2-}$ is diamagnetic because all the electrons in the nickel ion (Ni$^{2+}$) are paired in the low-spin octahedral complex. The other species exhibit unpaired electrons, which makes them paramagnetic.