Of the following complex ions, which is diamagnetic in natures?

Options

A. `[Ni(CN)_(4)]^(2-)`
B. `[CuCl_(4)]^(2-)`
C. `[CoF_(6)]^(3-)`
D. `[NiCl_(4)]^(2-)`

Answer

A

Explanation

Electronic configuration of `Ni^(2+) " is "[ Ni ( CN)_(4)]^(2-) " is " Ni^(2+)=3d^84s^0`

`therefore [Ni(CN)_(4)]^(2-)` is diamagnetic (because of the absence of unpaired electrons).