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प्रश्न
Read the passage carefully and answer the questions that follow.
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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:
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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+
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उत्तर
(a) D Energy is directly proportional to the wave number. Maximum energy of light is required for an electron to jump from t2g to eg in case of [CrD6]3-.
OR
A, The splitting caused in least in this case as the energy required for electron to jump from t2g to eg., is minimum.
(b) [CrB6]3+, wavelength of light absorbed is `1/17830 = 560` nm for the complex while `1/13640` = 733 nm for [CrA6]3- complex.
(c)
- [CrCl6]3-, Hexachloridochromate (III) ion
- [Cr(NH3)6]3+, Hexaamminechromium (III) ion
\[\ce{A = Cl-, B = H2O, C = NH3, D = CN-}\]
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संबंधित प्रश्न
The hexaquo manganese(II) ion contains five unpaired electrons, while the hexacyanoion contains only one unpaired electron. Explain using Crystal Field Theory.
Draw the structures of the following :
(1) XeF6
(2) IF7
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.
\[\ce{[CoF6]^{3-}, [Fe(CN)6]^{4-} and [Cu(NH3)6]^{2+}}\].
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 |
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 correct order of increasing crystal field strength in following series:
The magnitude of CFSE depends upon ______
Using crystal field theory, write the electronic configuration of d5 ion, if Δ0 > P.
The value of the spin only magnetic moment for one of the following configurations is 2.84 BM. The correct one is:
