Explain on the basis of valence bond theory that [Ni(CN)_(4)]^(2-) ion with square planar structure is diamagnetic and the [NiCl_(4)]^(2-) ion with tetrahedral geometry is paramagnetic.

Explain on the basis of valence bond theory that [Ni(CN)_(4)]^(2-) ion

1.	Explain on the basis of valence bond theory that [Ni(CN)_(4)]^(2-) ion with square planar structure is diamagnetic and the [NiCl_(4)]^(2-) ion with tetrahedral geometry is paramagnetic.
Answer» Solution :`[Ni(CN)_(4)]^(2-)` Nickel in the above complex ion is in +2 oxidation state. Formation of `[Ni(CN)_(4)]^(2-)` may be explained through hybridisation as FOLLOWS : Configuration of `Ni^(2+)` Pairing of ELECTRONS followed by `dsp^(2)` hybridisation It is because of the strong ligand `CN^(-)` that the pairing of electrons takes place. As there are no unpaired electrons, the complex is diamagnetic. `[NiCl_(4)]^(2-)` Formation of the above complex may be explained through hybridisation. Ni in the above complex is in +2 oxidation state i.e., as `Ni^(2+)`. Configuration of `Ni^(2+)` No pairing of electrons `sp^(3)` hybridisation As `Cl^(-)` is a weak ligand, pairing of electrons does not take place. `sp^(3)` hybridisation of orbitals takes place giving RISE to tetrahedral geometry. As there are two unpaired electrons in the complex, it is paramagnetic.