Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following
(a) `[CoF_(6)]^(3-), [Co(H_(2)O)_(6)]^(2+), [Co(CN)_(6)]^(3-)`
(b) `FeF_(6)^(3-), [Fe(H_(2)O)_(6)]^(2+), [Fe(CN)_(6)]^(4-)`

Explanation

`n=0, mu=sqrt(n(n+2))=0`. Hence, it is diamagnetic.
(ii) `FeF_(6)^(3-)" has "Fe^(3+)=3d^(5)=t_(2g)^(3)e_(g)^(2),n=5,mu=sqrt(5(5+2))=sqrt(35)=5.92 BM`
(`F^(-)` is a weak field ligand, `Delta_(0)ltP`)
`[Fe(H_(2)O)_(6)]^(2+)` has `Fe^(2+)=3d^(6)=t_(2g)^(4)e_(g)^(2), n=4, mu=sqrt(4(4+2))=sqrt(24)=4.9BM`
(`H_(2)O` is a weak field ligand, `Delta_(0)ltP`)
`[Fe(CN)_(6)]^(4-)" has "Fe^(2+)=3d^(6)=t_(2g)^(6)e_(g)^(0), n=0, mu=0` (diamagnetic), (`CN^(-)` is a strong field ligand, `Delta_(0)gtP`)