Question

Which of the following complex compounds will exibit highest paramagnetic behavior?

• A. $\left[Ti\right({NH}_3{)}_6{]}^{3+}$
• B. $\left[Cr\right({NH}_3{)}_6{]}^{3+}$
• C. $\left[Co\right({NH}_3{)}_6{]}^{3+}$
• D. $\left[Zn\right(N{H}_3{)}_4]{Cl}_2$

Answer 1

The correct option is A $\left[Ti\right({NH}_3{)}_6{]}^{3+}$

$T{i}^{3+}-\left[Ne\right]{3s}^2{3p}^6{4s}^0{3d}^1$

${Zn}^{2+}-\left[Ne\right]{3s}^2{3p}^6{4s}^0{3d}^{10}\}-$ not much paramagnetic

${Cr}^{3+}\to d_3$ configuration $\to t_{2g}$ means paramagnetic

${Co}^{3+}\to d_6$ configuration $\to {NH}_3$ strong field ligand

So, it would be $d_6$ (low spin) diamagnetic.