Question

CFSE of complex ion [Co(CN)6]3- is (neglect pairing energy)​

Answer 1

Answer:

-2.4(octhedral energy)

Points to be kept in mind :

1) -CN is a strong field lignd

2) the expression for CFSE(in attachement)

Please refer the solution in picture

Hope this answer helped you ✌

Answer 2

CFSE of $[Co(CN)_6]^{3-}$ is -2.4∆.

• The complex is $[Co(CN)_6]^{3-}$.
• The oxidation state of Co is as follows-
• x-6×1=-3
• x=+3.
• Thus oxidation state of Co is +3.
• So, Co exists as a $d^6$ species.
• Here cyanide is a strong field ligands so it makes pairing.
• Thus the $t_{2g}$ orbital has six electrons.
• Thus CFSE is as follows-
• -0.4×6=-2.4.
• Thus CFSE of $[Co(CN)_6]^{3-}$ is -2.4∆.