Low spin complex of `d^6`-cation in an octahedral field will have the following energy:

Options

A. `-(2)/(5)Delta_(0) + 2P`
B. `-(2)/(5)Delta_(0) + P`
C. `-(12)/(5)Delta_(0)+P`
D. `-(12)/(5)Delta_(0)+3P`

Answer

D

Explanation

Electronic configuration of `d^(6)`-cation in low spin
CFSE=(-0.4x+0.6y)`Delta_(0)`
`=(-(2)/(5)x+(3)/(5)y)Delta_(0)`
x = number of electrons in `t_(2g)=6`
y = number of electrons in `e_(g)=0`
`therefore CFSE =(-(2)/(5)xx6+0)Delta_(0)=-(12)/(5)Delta_(0)`
Number of electrons pairs = 3
`therefore` Pairing energy = 3 P
`therefore` Energy of low spin `d^(6)` cation `=-(12)/(5)Delta_(0)+3P`