Deck 20: The D-Metal Complexes: Electronic Structure and Spectra

Question 1

Identify the correct statement:

A) In an octahedral crystal field, the d orbitals are split into t_2g and e_g sets separated by the ligand-field splitting parameter _O.
B) The triply degenerate t_2g set is higher in energy than the doubly degenerate e_g set in an octahedral crystal field.
C) The e_g set of orbitals is composed of degenerate d_xy and d_xz atomic orbitals.

Answer 1

A

Question 2

What does the ligand field splitting parameter, _O?, depend on?
(i) Ligand's position in spectrochemical series.
(ii) The colour of the complex.
(iii) The charge on the central metal atom.

A) (i) and (ii)
B) (ii) and (iii)
C) (i) and (iii)

Answer 2

C

Question 3

Which of the following electronic configurations can produce either high or low spin complex?

A) d³
B) d⁵
C) d⁸

Answer 3

B

Question 4

The square planar geometry is preferred over tetrahedral when

A) metal has a d⁸ electronic configuration with strong field ligands.
B) the ligands are early in the spectrochemical series.
C) the metal is in low oxidation state.

Question 5

Identify the correct statement(s):
(i) Ligand field theory is based on molecular orbital theory.
(ii) Ligand field theory can explain the spectrochemical series.
(iii) Ligand filed theory does not take into account the s and p atomic orbitals on the metal.

A) (i) and (ii)
B) (ii) and (iii)
C) (i) and (iii)

Question 6

Which of the spectroscopic terms, ¹G, ³F, ¹D, ³P or ¹S, found for d² electronic configuration, is the ground state term?

A) ³F
B) ¹S
C) ³P

Question 7

Which information can be extracted from Tanabe-Sugano diagrams if the UV-Vis spectrum is known?
(i) Racha's parameter B
(ii) value of _O
(iii) The ground-state term for the given d-electron configuration.

A) (i) and (ii)
B) (i), (ii) and (iii)
C) (ii) and (iii)

Question 8

If the metal is in low oxidation state and the ligands contain empty orbitals, then:

A) Metal-to-ligand charge-transfer transitions are observed.
B) Ligand-to-ligand charge-transfer transitions are observed.
C) Ligand-to-metal charge-transfer transitions are observed.

Question 9

Which of the following transitions are forbidden based on the spin selection rule?

A) ²E_g ← ⁴A_2g
B) ⁴T_1g ← ⁴A_2g
C) ⁴T_2g ← ⁴A_2g

Question 10

Identify the correct statement(s):
(i) Luminescent complexes radiate energy after electronic excitation by the absorption of radiation.
(ii) Phosphorescence takes place without change in multiplicity between excited and ground state.
(iii) Luminescence competes with other non-radiative decays.

A) (i) and (iii)
B) All are correct
C) (ii) and (iii)