APPLICATION OF VALENCE BOND THEORY (Octahedral complex)

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APPLICATION OF VALENCE BOND THEORY:
1)Octahedral Complex:
a)[Fe(CN)6]3-complex:
In this ion coordination number of Fe atom is six and hence the given complex ion is octahedral in shap.In this ion,Fe is present as Fe3+ ion whose valence-shell configuration is 3d5,according to hund’s rule ,each of the five electron in 3d- orbitals is unpaired in free Fe3+ion and hence the number of unpaired electron(n) is equal to 5.how ever ,magnetic study of [Fe(CN)6]3- ion has shown that this ion has one unpaired electron(n).Hence is paramagnetic.

b)[FeF6]3- complex:
In this ion, the coordination number of Fe is six and hence the given complex ion has octahedral geometry.Here iron is present as Fe3+ whose valence shell electronic confriguration is 3d54s04p0.Each of the five electron is unpaired and hence n=5 .Magnetic properties of the given ion have also shown that the ion has five unpaired electrons and hence paramagnetic corresponding to presence of five unpaired electron.


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