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

Options

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

Answer

c

Explanation

Electronic configuration of NI : `[Ar]3d^(8)4s^(2)`

Paramagnetic behaviour is possible when pairing does not take place. i.e., 3d will not participate in bonding and hybridisation will be `sp^(3)` including 4s and 4p. Thus structure is tetrahedral . When pairing takes place (in pressure of strong ligand field),

`ds^(2)` hybrid orbitals arrange in square planar structure.
`Ni^(2+)` : paramagnetic , `sp^(3)` , tetrahedral
`Ni^(2+)` : diamagnetic , `dsp^(2)` , square planar.