\((A)\) In octahedral complex: \(\left[ M \left( H _{2} O \right)_{6}\right]^{2+}\)
\(C.F.S.E.\) \(=\left(-0.4 \Delta_{0}\right) \times 4+\left(+0.6 \Delta_{0}\right) \times 2+0 \times P\)
\((B)\) In tetrahedral complex: \(\left[ M \left( H _{2} O \right)_{4}\right]^{2+}\)
\(C.F.S.E.\) \(=\left(-0.6 \Delta_{t}\right) \times 3+\left(+0.4 \Delta_{t}\right) \times 3+0 \times P\)
\(=-0.6 \Delta_{ t }\)
$(I)$ સિસ $- [Co(NH_3)_2(en)_2]^{3+}$ $(II)$ ટ્રાન્સ $-[IrCl_2(C_2O_4)_2]^{3-}$
$(III)\, [Rh(en)_3]^{3+}$ $(IV)$ સિસ $-[Ir(H_2O)_3Cl_3$
$(I)\ [Pt(NH_3)_6]Cl_4$
$(II) [Cr(NH_3)_6]Cl_3$
$(III) [Co(NH_3)Cl_2]Cl$
$(IV) K_2[PtCl_6]$
$(i)$ $\left[ FeF _{6}\right]^{3-}$
$(ii)$ $\left[ Co \left( NH _{3}\right)_{6}\right]^{3+}$
$(iii)$ $\left[ NiCl _{4}\right]^{2-}$
$(iv)$ $\left[ Cu \left( NH _{3}\right)_{4}\right]^{2+}$