3d 4s 4p Hybridisation Coordination number - Hybridisation - d sp Hybridised orbitals of the metal ion in the complex 3d d s p Hybridised orbitals Geometry Octahedral In this complex inner d orbitals are involved in hybridisaion and hence the complex is called inner orbital complex Magnetic property No. of unpaired electrons = ; Hence paramagnetic Magnetic moment (Using spin only formula) µ s = n(n+ ) = ( + ) = . BM Illustration Complex [CoF ] - Central metal atom and its outer electronic configuration Co + : 3d , 4s Outer orbitals of metal atom/ion 3d 4s p Nature of ligand F - Weak field ligand and hence no pairing of 3d electrons in the metal Outer orbitals of metal atom/ion in presence of ligand 3d 4s 4p 4d Hybridisation Coordination number - Hybridisation - sp d XII U5 Coordination XII U5 Coordination - - - - Complex [CoF ] - Hybridised orbitals of the metal atom in the complex 3d sp d Hybridised orbitals 4d Geometry Octahedral In this complex outer d orbitals are involved in the hybridisaion and hence the complex is called outer orbital complex Magnetic property No. of unpaired electrons = ; Hence paramagnetic Magnetic moment (Using spin only formula) µ s = n(n+ ) = ( + ) = .
BM Limitations of VBT Eventhough VBT explains many of the observed properties of complexes, it still has following limitations . It does not explain the colour of the complex. . It considers only the spin only magnetic moments and does not consider the other components of magnetic moments.
. It does not provide a quantitative explanation as to why certain complexes are inner orbital complexes and the others are outer orbital complexes