Advertisements
Advertisements
Questions
State the superiority of crystal field theory over valence bond theory.
Why is crystal field theory regarded superior to valence bond theory?
Advertisements
Solution
Despite the constraints mentioned above, crystal field theory outperforms valence bond theory. The crystal field theory is thought to be preferable to the valence bond theory for the following reasons.
- Crystal field theory describes the magnetic properties of complexes in detail and provides an explanation for how magnetic moments vary with temperature. VBT fails to provide these additional details.
- Crystal field theory measures the stability of a complex. With this measure, the geometry gained by a particular complex can be predicted. VBT does not include such a measure.
- Crystal field theory explains certain thermodynamic and kinetic features of complexes. VBT does not offer such an explanation.
- Only crystal field theory can explain the observed d-d transitions in complexes and their hue. The VBT does not explain spectroscopic features or complex coloration adequately.
APPEARS IN
RELATED QUESTIONS
Draw figure to show the splitting of d orbitals in an octahedral crystal field.
Why are low spin tetrahedral complexes rarely observed?
Write the electronic configuration of Fe(III) on the basis of crystal field theory when it forms an octahedral complex in the presence of (i) strong field, and (ii) weak field ligand. (Atomic no.of Fe=26)
Draw the structures of the following :
(1) XeF6
(2) IF7
Complete and balance the following reactions:
\[\ce{P4 + H2SO4 ->}\] ______ + ______ + ______
Atomic number of \[\ce{Mn}\], \[\ce{Fe}\] and \[\ce{Co}\] are 25, 26 and 27 respectively. Which of the following inner orbital octahedral complex ions are diamagnetic?
(i) \[\ce{[Co(NH3)6]^{3+}}\]
(ii) \[\ce{[Mn(CN)6]^{3-}}\]
(iii) \[\ce{[Fe(CN)6]^{4-}}\]
(iv) \[\ce{[Fe(CN)6]^{3-}}\]
An aqueous pink solution of cobalt (II) chloride changes to deep blue on addition of excess of HCl. This is because:
(i) \[\ce{[Co(H2O)6]^{2+}}\] is transformed into \[\ce{[CoCl6]}^{4-}\]
(ii) \[\ce{[Co(H2O)6]^{2+}}\] is transformed into \[\ce{[CoCl4]}^{2-}\]
(iii) tetrahedral complexes have smaller crystal field splitting than octahedral complexes.
(iv) tetrahedral complexes have larger crystal field splitting than octahedral complex.
Give the electronic configuration of the following complexes on the basis of Crystal Field Splitting theory.
\[\ce{[CoF6]^{3-}, [Fe(CN)6]^{4-} and [Cu(NH3)6]^{2+}}\].
\[\ce{CuSO4 . 5H2O}\] is blue in colour while \[\ce{CuSO4}\] is colourless. Why?
Match the complex ions given in Column I with the hybridisation and number of unpaired electrons given in Column II and assign the correct code:
| Column I (Complex ion) | Column II (Hybridisation, number of unpaired electrons) |
| A. \[\ce{[Cr(H2O)6]^{3+}}\] | 1. dsp2, 1 |
| B. \[\ce{[Co(CN)4]^{2-}}\] | 2. sp3d2, 5 |
| C. \[\ce{[Ni(NH3)6]^{2+}}\] | 3. d2sp3, 3 |
| D. \[\ce{[MnF6]^{4-}}\] | 4. sp3, 4 |
| 5. sp3d2, 2 |
Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?
In a coordination entity, the electronic configuration of the central metal ion is t2g3 eg1
Draw the crystal field splitting diagram for the above complex.
The CFSE of [CoCl6]3– is 18000 cm–1 the CFSE for [CoCl4]– will be ______.
What is the difference between a weak field ligand and a strong field ligand?
What is crystal field splitting energy?
The correct order of intensity of colors of the compounds is ______.
Consider that d6 metal ion (M2+) forms a complex with aqua ligands and the spin only magnetic moment of the complex is 4.90 BM. The geometry and the crystal field stabilization energy of the complex are ______.
The complex that has highest crystal field splitting energy (Δ) is ______.
On the basis of Crystal Field theory, write the electronic configuration for the d5 ion with a strong field ligand for which Δ0 > P.
On the basis of crystal field theory, write the electronic configuration for the d5 ion with a weak ligand for which Δ0 < P.
On the basis of crystal field theory, write the electronic configuration for d4 with a strong field ligand for which Δ0 > P.
On the basis of Crystal Field Theory, write the electronic configuration of d4 ion if Δ0 > P.
