Advertisements
Advertisements
Question
[Fe(CN)6]4− and [Fe(H2O)6]2+ are of different colours in dilute solutions. Why?
Solution 1
The colour of a particular coordination compound depends on the magnitude of the crystal-field splitting energy, Δ. This CFSE in turn depends on the nature of the ligand. In case of [Fe(CN)6]4− and [Fe(H2O)6]2+, the colour differs because there is a difference in the CFSE. Now, CN− is a strong field ligand having a higher CFSE value as compared to the CFSE value of water. This means that the absorption of energy for the intra d-d transition also differs. Hence, the transmitted colour also differs.
Solution 2
In [Fe(CN)6]4−, CN− is a strong field ligand hence, pairing of electrons takes place.
In [Fe(H2O)6]4−, H2O is a weak ligand hence, pairing does not take place.
Because of their differing natures, these ligands show different magnitudes of crystal field splitting energy, resulting in varied wavelengths and colours.
APPEARS IN
RELATED QUESTIONS
Which of the following complexes will give a white precipitate on treatment with a solution of barium nitrate?
- [Cr(NH3)4SO4] Cl
- [Co(NH3)4Cl2] NO2
- [Cr(NH3)4Cl2]SO4
- [CrCl2(H2O)4]Cl
On adding NaOH to ammonium sulphate, a colourless gas with pungent odour is evolved, which forms a blue-coloured complex with Cu2+ ion. Identify the gas.
A solution of [Ni(H2O)6]2+ is green but a solution of [Ni(CN)4]2− is colourless. Explain.
What will be the correct order for the wavelengths of absorption in the visible region for the following?
[Ni(NO2)6]4−, [Ni(NH3)6]2+, [Ni(H2O)6]2+
Why a solution of [Ni(H2O)6]2+ is green while a solution of [Ni(CN)4]2− is colourless? (At. no. of Ni = 28)
Which of the following is the most likely structure of CrCl3.6H2O if `1/3` of total chlorine of the compound is precipitated by adding AgNO3 to its aqueous solution?
Which of the following complex will give a white precipitate with barium chloride solution?
The wavelength of light absorbed by [Cu(H2O)4]2+ is 600 nm. The crystal field splitting energy is ______
A solution of [Ni(H2O)6]2+ is green, but a solution of [Ni(CO)4] is colourless. Explain.
[Atomic number: Ni = 28]
Aqueous copper sulphate solution (blue in colour) gives a bright green solution with aqueous potassium chloride. Explain this experimental result.
Explain the violet colour of the complex [Ti(H2O)6]3+ on the basis of crystal field theory.
