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प्रश्न
The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of light in the visible region, for the complexes, \[\ce{[Co(NH3)6]^{3+}}\], \[\ce{[Co(CN)6]^{3-}}\], \[\ce{[Co(H2O)6]^{3+}}\]
विकल्प
\[\ce{[Co(CN)_6]^{3-} > [Co(NH3)6]^{3+} > [Co(H2O)6]^{3+}}\]
\[\ce{[Co(NH3)_6]^{3+} > [Co(H2O)6]^{3+} > [Co(CN)6]^{3-}}\]
\[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]
\[\ce{[Co(CN)6]^{3-} > [Co(H2O)6]^{3+} > [Co(NH3)6]^{3+}}\]
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उत्तर
\[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]
Explanation:
The CFSE of the ligands is in the order:
H2O < NH3 < CN−
Hence, excitation energies are in the order:
\[\ce{[Co(H2O)6]^{3+} < [Co(NH3)6]^{3+} < [Co(CN)6]^{3-}}\]
From the relation E = `"hc"/λ` ⇒ `"E" ∝ 1/λ`
The order of absorption of the wavelength of light in the visible region is:
\[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]
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संबंधित प्रश्न
How does the magnitude of Δo decide the actual configuration of d orbitals in a coordination entity?
How are the following conversions carried out?
Benzoic acid into metanitrobenzoic acid.
State the superiority of crystal field theory over valence bond theory.
Why are low spin tetrahedral complexes rarely observed?
The CFSE for octahedral \[\ce{[CoCl6]^{4-}}\] is 18,000 cm–1. The CFSE for tetrahedral \[\ce{[CoCl4]^{2-}}\] will be ______.
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 |
Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following:
\[\ce{[CoF6]^{3-}, [Co(H2O)6]^{2+}, [Co(Cn)6]^{3-}}\]
Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?
[Ni(H2O)6]2+ (aq) is green in colour whereas [Ni(H2O)4 (en)]2+ (aq)is blue in colour, give reason in support of your answer.
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.
Considering crystal field theory, strong-field ligands such as CN–:
The correct order of increasing crystal field strength in following series:
Using crystal field theory, write the electronic configuration of d5 ion, if Δ0 > P.
For octahedral Mn(II) and tetrahedral Ni(II) complexes, consider the following statements:
- Both the complexes can be high spin.
- Ni(II) complex can very rarely below spin.
- With strong field Ligands, Mn(II) complexes can be low spin.
- Aqueous solution of Mn (II) ions is yellow in colour.
The correct statements are:
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.
Read the passage carefully and answer the questions that follow.
|
Crystal field splitting by various ligands Metal complexes show different colours due to d-d transitions. The complex absorbs light of specific wavelength to promote the electron from t2g to eg level. The colour of the complex is due to the transmitted light, which is complementary of the colour absorbed. The wave number of light absorbed by different complexes of Cr ion are given below:
|
Answer the following questions:
(a) Out of ligands "A", "B", "C" and "D", which ligand causes maximum crystal field splitting? Why?
OR
Which of the two, “A” or “D” will be a weak field ligand? Why?
(b) Which of the complexes will be violet in colour? [CrA6]3- or [CrB6]3+ and why?
(Given: If 560 - 570 nm of light is absorbed, the colour of the complex observed is violet.)
(c) If the ligands attached to Cr3+ ion in the complexes given in the table above are water, cyanide ion, chloride ion, and ammonia (not in this order).
Identify the ligand, write the formula and IUPAC name of the following:
- [CrA6]3-
- [CrC6]3+
On the basis of Crystal Field Theory, write the electronic configuration of d4 ion if Δ0 > P.
