When degenerate d-orbitals of an isolated atom/ion come under influence of magnetic field of ligands, the degeneracy is lost. The two sets `t_(2g)(d_(xy),d_(yz),d_(xz))ande_(g)(d_(z^(2)),d_(x^(2)-y^(3)))` are either stabilized or destabilized depending upon the nature of magnetic field. It can be expressed diagramatically as : Value of CFS depends upon nature of ligand and a spectro-chemical series has been made experiment-ally, for tetrahedral complexes `Delta_(i)` is about 4/9 times to `Delta_(0)` (CFSE for octahedral complexes).

The energy lies in visible region and i.e., why electronic transition `t_(2_(g))hArre_(g)` are responsible for colour. Such transitions are not possible with `d^(0)` and `d^(10)` configuration.
The value of CFSE `(Delta_(a))` for complexes given below follow the order:
`{:([Co(NH_(3))_(6)]^(3+),[Rh(NH_(3))_(6)]^(3+),[Ir(NH_(3))_(6)]^(3+)),("(I)","(II)","(III)"):}`

Options

A. `IltIIltIII`
B. `IgtIIgtIII`
C. `IltIIgtIII`
D. I=II=III

Answer

A

Explanation

For a given ligand and charge of metal ion, CFSE increases from top to bottom in a group.