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प्रश्न
What is the spectrochemical series?
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उत्तर
Crystal field splitting, Δo depends on the field produced by the charge present on the ligand and the metal ion. Some ligands can produce strong fields and in such a case the splitting is more, while others produce weak fields due to which the splitting of d-orbitals is less. Generally, ligands can be arranged in a series in the order of their increasing field strength as follows:
\[\ce{I^- < Br^- < SCN^- < Cl^- < S^2- < F^- < OH^- < C2O^{2-}_4 < H2O < NCS^- < EDTA^{4-} < NH3 < en < CN^- < CO}\]
This type of series is called a spectrochemical series. It is determined by experimental facts based on the absorption of light by complexes formed with different ligands.
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संबंधित प्रश्न
Draw figure to show the splitting of d orbitals in an octahedral crystal field.
How does the magnitude of Δ0 decide the actual configuration of d orbitals in a coordination entity?
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
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.
On the basis of crystal field theory explain why Co(III) forms paramagnetic octahedral complex with weak field ligands whereas it forms diamagnetic octahedral complex with strong field ligands.
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.
The magnitude of CFSE depends upon ______
Using crystal field theory, write the electronic configuration of d5 ion, if Δ0 > P.
What is crystal field splitting energy?
The complex that has highest crystal field splitting energy (Δ) is ______.
