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प्रश्न
What is the difference between a weak field ligand and a strong field ligand?
Explain the difference between a weak field ligand and a strong field ligand.
Write the difference between a strong field ligand and a weak field ligand.
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उत्तर
| S.No. | Weak Field Ligand | Strong Field Ligand |
| 1. | A ligand that produces a small splitting of the d-orbitals in the central metal ion. | A ligand that produces a large splitting of the d-orbitals in the central metal ion. |
| 2. | These are the ligands used in octahedral complexes in which the crystal field stabilization energy Δo is less than the pairing energy (P) in a single orbital. | These are the ligands used in octahedral complexes in which the crystal field stabilization energy Δo is greater than the pairing energy (P). |
| 3. | Complexes formed by these ligands are also known as high-spin complexes. | Complexes formed by these ligands are also known as low-spin complexes |
| 4. | The complexes formed are generally paramagnetic. | The complexes formed are mostly diamagnetic or relatively less paramagnetic. |
| 5. | Examples of weak field ligands include I−, Br−, Cl−, and H2O. | Examples of strong field ligands include NH3, CN−, Co. |
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संबंधित प्रश्न
On the basis of crystal field theory, write the electronic configuration for d4 ion if Δ0 > P.
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
Give the electronic configuration of the following complexes on the basis of Crystal Field Splitting theory.
\[\ce{[CoF6]^{3-}, [Fe(CN)6]^{4-} and [Cu(NH3)6]^{2+}}\].
Arrange following complex ions in increasing order of crystal field splitting energy (∆O):
\[\ce{[Cr(Cl)6]^{3-}, [Cr(CN)6]^{3-}, [Cr(NH3)6]^{3+}}\].
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:
\[\ce{[CoF6]^{3-}, [Co(H2O)6]^{2+}, [Co(Cn)6]^{3-}}\]
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:
\[\ce{[FeF6]^{3-}, [Fe(H2O)6]^{2+}, [Fe(CN)6]^{4-}}\]
[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–:
Crystal field stabilising energy for high spind4 octahedral complex is:-
What is the spectrochemical series?
What is crystal field splitting energy?
On the basis of crystal field theory, write the electronic configuration for d4 with a strong field 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:
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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+
The value of the spin only magnetic moment for one of the following configurations is 2.84 BM. The correct one is:
