Describe the structure and magnetic behaviour of `[Ni(CN)_4]^(2-)` ion on the basis of valence bond theory.

Explanation

(i) Orbitals of `Ni^(2+)` ion
(ii) In presence of strong ligand `CN^(-)` spin pairing takes place and `dsp^(2)` hybridisation takes place.
`dsp^(2)` hybridised orbital of `Co^(3+)`
(iii) Four pairs of electrons, one from each `CN^(-)` occupy the four hybrid orbitals. Thus the complex has square planar geometry and diamagnetic because of the absence of unpaired electrons.
`[Ni(CN)_(4)]^(2-)` Complex orbitals :
`ul("For " [Ni(CN)_(4)])` :- `ul("Complex")`
(i) Type of hybridisation : `dsp^(2)`
(ii) Geometry : Square planar
(iii) Magnetic property : Diamagnetic.