Question

Which of the following is inner orbital complex as well as diamagnetic in nature?

• A. $\left[Ir\right(H_{2}O{)}_6{]}^{3+}$
• B. $\left[Ni\right(N{H}_3{)}_6{]}^{2+}$
• C. $\left[Cr\right(N{H}_3{)}_6{]}^{3+}$
• D. $\left[Co\right(N{H}_3{)}_6{]}^{2+}$

Answer 1

Answer: (A)

$\left[Ir\right(H_{2}O{)}_6{]}^{3+}$

The complex which forms an inner orbital complex as well as show diamagnetic property is $\left[Ir\right(H_{2}O{)}_6{]}^{3+}$ because Ir is a metal of 5d series and 5d series metals have more diffused and large orbitals than 3d metals (in the rest of the options) and therefore the ligands bond with the metal very closely and hence forms more stable inner orbital complexes and the electrons are paired up irrespective of the ligands present. Hence option 1 is correct.