The Valence Bond Theory (VBT) explains the formation, magnetic behaviour and geometrical shapes of coordination compounds whereas 'The Crystal Field…

The Valence Bond Theory (VBT) explains the formation, magnetic behaviour and geometrical shapes of coordination compounds whereas 'The Crystal Field Theory' for coordination compounds is based on the effect of different crystal fields (provided by ligands taken as point charges), on the degeneracy of d-orbital energies of the central metal atom/ion. The splitting of the d-orbitals provides different electronic arrangements in strong and weak crystal fields. The crystal field theory attributes the colour of the coordination compounds to d-d transition of the electron. Coordination compounds find extensive applications in metallurgical processes, analytical and medicinal chemistry. Answer the following questions :

What is crystal field splitting energy ?

Give reason for the violet colour of the complex $\displaystyle \left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ on the basis of crystal field theory.

$\displaystyle \left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$ is paramagnetic while $\displaystyle \left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}$ is diamagnetic. Explain why. [Atomic No. : $\displaystyle \mathrm{Cr}=24, \mathrm{Ni}=28$ ]

Explain why $\displaystyle \left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$ is an inner orbital complex, whereas $\displaystyle \left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ is an outer orbital complex. [Atomic No. : $\displaystyle \mathrm{Fe}=26$ ]