Crystal Field Theory (CFT)

A complex of metal ${\mathrm{M}}^{\mathrm{n}+}$ has the following electronic distribution in $\mathrm{d}$ orbitals,

The neutral M has a ground state electronic configuration of $\left[\mathrm{Ar}\right] 4{\mathrm{s}}^2 3{\mathrm{d}}^6.$ Which of the following complexes is consistent with the electronic distribution of ${\mathrm{M}}^{\mathrm{n}+}$ (as described above)?

In which of the following complexes, magnetic moment will change when all the ligands are replaced by ${\mathrm{CN}}^{-}$ ion to form a cyano complex?

In Wilkinson's catalyst, the hybridization of central metal ion and its shape are respectively:

 An octahedral complex $\text{'}\mathrm{X}\text{'}$ with magnetic moment $3.87 \mathrm{BM}$ may have:

(a) ${\mathrm{d}}^3$ configuration with weak field ligand.

(b) ${\mathrm{d}}^3$ configuration with strong field ligand.

(c) ${\mathrm{d}}^6$ configuration with strong field ligand.

(d) ${\mathrm{d}}^7$ configuration with weak field ligand.

Crystal field splitting energies for octahedral $\left({\mathrm{\Delta }}_0\right)$ and tetrahedral $\left({\mathrm{\Delta }}_{\mathrm{t}}\right)$ geometries caused by the same ligands are related through the expression

The order of octahedral crystal field energy for $\text{'}{\mathrm{e}}_{\mathrm{g}}\text{'}$ orbitals are

According to crystal field theory, total number of unpaired electrons present in the following molecules ${\left[{\mathrm{NiCl}}_4\right]}^{2-}, {\left[\mathrm{Ni}(\mathrm{CN}{)}_4\right]}^{2-}$ and ${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ will be

For next two question please follow the same

When degenerate $\mathrm{d}$-orbitals of an isolated atom/ion come under influence of magnetic field of ligands, the degeneracy is lost. The two set t_2g (d_xy, d_yz,d_xz) and e_g (d_z², d_x²-y²) are either stabilized or destabilized depending upon the nature of magnetic field. It can be expressed diagrammatically as :



Value of $\mathrm{CFSE}$ depends upon nature of ligand and a spectrochemical  series has been made experimentally, for tetrahedral complexes, $\mathrm{\Delta }$ is about $4/9$  times to ${\Delta }_0$ ($\mathrm{CFSE}$ for octahedral complex). This energy lies in visible region and i.e., why electronic transition are responsible for colour. Such transitions are not possible with ${\mathrm{d}}^0$ and ${\mathrm{d}}^{10}$ configuration.

${\mathrm{Cr}}^{3+}$ form four complexes with four different ligands which are [Cr(Cl)₆]^3-, [Cr(H₂O)₆]³⁺, [Cr(NH₃)₆]³⁺ and [Cr(CN)₆]^3-. The order of $\mathrm{CFSE}$ $\left({\Delta }_0\right)$ in these complexes is in the order :

Increasing crystal field strength of the different ligands is :

When all the ligands are replaced by ${\mathrm{CN}}^{-}$ ion to form a cyano complex, which of the following complexes show magnetic moment?

${\mathrm{Cr}}^{3+}$ forms four complexes with four different ligands which are ${\left[{\mathrm{CrCl}}_6\right]}^{3-}, {\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}, {\left[\mathrm{Cr}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$ and ${\left[\mathrm{Cr}(\mathrm{CN}{)}_6\right]}^{3–}$. The order of crystal field stabilization energy $\mathrm{CFSE}\left({\mathrm{\Delta }}_{\mathrm{o}}\right)$ in these complexes are

Which of the following complex ions has electrons that are symmetrically filled in both ${\mathrm{t}}_{2\mathrm{g}}$ and ${\mathrm{e}}_{\mathrm{g}}$ orbitals?

Which of the following statement is incorrect regarding below complexes?
$\mathrm{P}={\left[\mathrm{Cu}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}; \mathrm{Q}={\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{2+}; \mathrm{R}={\left[\mathrm{Co}{\left(\mathrm{CN}\right)}_6\right]}^{3-}; \mathrm{S}={\left[\mathrm{Co}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]}^{3-}$

A d-block element forms an octahedral complex, but its magnetic moment remains the same either in strong field or in weak field ligand. Among the following, which is/are correct?

The coordination complex that shows zero crystal field stabilisation energy ($\mathrm{CFSE}$) is:

Consider the following complex ions -

$\underset{ \mathrm{I} }{{\left[{\mathrm{CrCl}}_6\right]}^{3-}} , \underset{ \mathrm{II}}{{\left[\mathrm{Cr}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}}, \underset{\mathrm{III}}{{\left[\mathrm{Cr}(\mathrm{CN}{)}_6\right]}^{3-}}$

Give the correct order of crystal field splitting energy.

For the complex, ${\left[\mathrm{Ti}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}_{}^{3+}$ the value of crystal field splitting ( ${\mathrm{\Delta }}_0$ ) is $243 \mathrm{kJ} {\mathrm{mol}}^{-1}$. The crystal field stabilization energy (CFSE) in the complex (in $\mathrm{kJ} {\mathrm{mol}}^{-1}$) would be :

What is the hybridization of $\mathrm{Fe}$ in the brown ring formation?

Which of the following is true about  $\left[\text{Ni}{\left(\text{CO}\right)}_4\right]\text{,}{\left[\text{Ni}{\left(\text{CN}\right)}_4\right]}^{2-}\text{and}{\left[\text{Ni}{\text{Cl}}_4\right]}^{2-}$?