Discussion Forum

$NiCl_{2}[P(C_{2}H_{5})_{2}(C_{6}H_{5})]_{2}$ exhibits temperature dependent magnetic behaviour (paramagnetic/diamagnetic) the coordination geometries of $Ni^{2+}$ in the paramagnetic and diamagnetic states are respectively 

Answer:

Explanation:

In the given complex, $NiCl_{2}[P(C_{2}H_{5})_{2}(C_{6}H_{5})]_{2}$  nickel is in + 2 oxidation state and the ground state electronic configuration of  $Ni^{2+}$ ion in the free gaseous state is

For the given four-coordinated complex to be paramagnetic, it must Possess unpaired electrons in the valence shell. To satisfy this condition, four lone pairs from the four ligands occupy the four  $sp^{3}$ hybrid orbital as,

Therefore, the Geometry of the paramagnetic complex must be tetrahedral. On the other hand, for the complex to be diamagnetic, there should not be any unpaired electrons in the valence shell. This condition can be fulfilled by pairing electrons of 3d orbitals against Hund's rule as

The above electronic arrangements give dsp² hybridizations and therefore square-planar geometry to the complex