`[NiCl_2 {P(C_2H_5)_2(C_6H_5)}_2]` exhibits temperature dependent magnetic behaviour (paramagnetic/diamagnetic). The coordination geometries of `Ni^(2+)` in the paramagnetic and diamagnetic states are respectively

Options

A. tetrahedral and tetrahedral
B. square planar and square planar
C. tetrahedral and square planar
D. square planarand tetrahedral

Answer

C

Explanation

`[NiCl_2 {P(C_2H_5)_2(C_6H_5)}_2]` contains `Ni^(2+)` having the electronic configuration as under:

In the high `sp^3` state, it iš paramagnetic with sphybridization giving tetrahedral geometry. In the low spin state (unpaired electrons pair up), it is diamagnetic with `dsp^2` hybridization giving square planar geometry.