In the crystal structure of CuF 2 , the Cu 2 + is six-coordinate with four F - at a distance of 1 . 93 A ° and two F - at 2 . 27 A ° . Explain the reason for this.

The structure of CuF 2 can be explained using Jahn-Teller distortion. In CuF 2 , elongation Jahn-Teller distortion occurs. Here, when the degeneracy is broken to obtain the lower energy state leading to stabilization of d - orbitals with Z component, while the orbitals not having the Z component are more destabilized due to the high energy state. This leads to tetragonal distortion of CuF 2 . Tetragonal distortion of an octahedral CuF 2 . It happens as dry and d x 2 - y 2 orbitals have greater overlap with the ligands orbital resulting higher energy level. Since the d x 2 - y 2 orbital is anti-bonding, it increases the energy due to the elongation. The d xy orbital of Cu 2 + is non-bonding, but it is destabilized due to the interaction with ligands and, hence, in CuF 2 both axial bonds are elongated and of equatorial bonds are shorter and of the same length. The orbital looses degeneracy by distortion making CuF 2 more stable.

E M B I B E

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 12

HARD

JEE Advanced

IMPORTANT

Earn 100

Calculate the crystal field stabilisation energy for $d^{8}$ ion such as ${Ni}^{2 +}$ in an octahedral and tetrahedral complexes. Use the unit of $Δ_{o}$ in both the cases. Which is the most stable? State any assumptions made.

Important Questions on Coordination Compounds

HARD

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 13

Calculate the spin only magnetic moment for a

d^{8}

ion in an octahedral, square planar and tetrahedral ligand fields.

HARD

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 14

Show by means of a diagram how the pattern of

d -

orbital splitting changes as an octahedral complex undergoes tetragonal distortion and eventually becomes a square planar complex.

HARD

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 16

Why are the compounds of

{Ti}^{4 +}

and

{Zn}^{2 +}

typically white? Why are

{Mn}^{2 +}

compounds very pale in colour? What are

d - d

transitions spin allowed for a

d^{5}

ion?

MEDIUM

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 17

What is the spectrochemical series and its importance?

MEDIUM

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 18

Given that the maximum adsorption in the

d - d

peak for

{[Ti {(H_{2} O)}_{6}]}^{3 +}

occurs at

20300 {cm}^{- 1}

. Predict where the peaks will occur for

{[Ti {(CN)}_{6}]}^{3 -}

and

{[Ti {(Cl)}_{6}]}^{3 -}

.

HARD

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 19

Describe how

Δ_{o}

changes as the charge on the central metal changes from

M^{2 +}

to

M^{3 +}

and how it changes in a vertical group or triad between a first row, second row or third row transition element.

MEDIUM

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 20

What would you expect the crystal field stabilisation energy to be and what value of magnetic moment would you expect for the following complexes?

(a) ${[{CoF}_{6}]}^{3 -}$

(b) ${[Co {({NH}_{3})}_{6}]}^{3 +}$

(c) ${[Fe {(H_{2} O)}_{6}]}^{2 +}$

(d) ${[Fe {(CN)}_{6}]}^{4 -}$

(e) ${[Fe {(CN)}_{6}]}^{3 -}$

HARD

JEE Advanced

IMPORTANT

Concise Inorganic Chemistry>Chapter 6 - Coordination Compounds>Exercise 1>Q 21

In the crystal structure of ${CuF}_{2}$ , the ${Cu}^{2 +}$ is six-coordinate with four $F^{-}$ at a distance of $1.93 \overset{°}{A}$ and two $F^{-}$ at $2.27 \overset{°}{A}$ . Explain the reason for this.