Using valence bond theory, explain the following in relation to the complexes given below : `[Mn(CN)_(6)]^(3-), [Co(NH_(3))_(6)]^(3+),[Cr(H_(2)O)_(6)]^(3+),[FeCl_(6)]^(4-)`
(i) Type of hbridisation. (ii) Inner or outer orbital complex. (iii) Magnetic behaviour. (iv) Spin only magnetic moment value.

Explanation

In `[Mn(CN)_(6)]^(3-),Mn^(3+)=3d^(4)`

(i) `d^(2)sp^(3)` - hybridisation
(ii) Inner orbital complex
(iii) Paramagnetic (two unpaired electrons)
(iv) `mu = sqrt(2(2+2))=srt8 = 2.83BM`
In `[Co(NH_(3))_(6)]^(3+), Co^(3+)=3d^(6)`

(i) `d^(2)sp^(3)`- hybridisation
(ii) Inner orbital complex
(iii) Diamagnetic (No unpaired electron),
(iv) `mu=0.`
In `[Cu(H_(2)O)_(6)]^(3+), Cr^(3+)=3d^(3)`

(i) `d^(2)sp^(3)`- hybridisation
(ii) Inner orbital complex
(iii) Paramagnetic (3 unpaired electrons)
(iv) `mu=sqrt((3(3+2)))=sqrt(15)=3.87BN`
In `[FeCl_(6)]^(4-), Fe^(2+)=3d^(6)`

(i) `sp^(3)d^(2)-` hybridisation
(ii) Outer orbital complex
(iii) Paramagnetic (4 unpaired electrons )
(iv) `mu=sqrt(4+2)=sqrt(24)=4.9BM`