Which complex of Co2+ will have the weakest crystal field splitting –...
Which complex of Co2+ will have the weakest crystal field splitting –...
Crystal Field Splitting in Complexes of Co2+
The crystal field splitting in transition metal complexes is determined by the ligands surrounding the central metal ion. The ligands create an electric field that interacts with the d-orbitals of the metal ion, causing a splitting of the energy levels. The magnitude of this splitting determines the color and magnetic properties of the complex.
In general, ligands can be divided into two categories: weak field ligands and strong field ligands. Weak field ligands cause a small splitting of the d-orbitals, resulting in a high-spin configuration, while strong field ligands cause a large splitting, leading to a low-spin configuration.
[CoCl6]4-
Chloride ions (Cl-) are weak field ligands. They have a small spatial extent and do not strongly interact with the d-orbitals of the metal ion. As a result, the crystal field splitting in [CoCl6]4- will be relatively small, leading to a high-spin configuration.
[Co(CN)6]4-
Cyanide ions (CN-) are strong field ligands. They have a large spatial extent and strongly interact with the d-orbitals of the metal ion. This results in a large crystal field splitting, leading to a low-spin configuration.
[Co(NH3)6]2+
Ammonia molecules (NH3) are weak field ligands. They have a small spatial extent and do not strongly interact with the d-orbitals of the metal ion. Therefore, the crystal field splitting in [Co(NH3)6]2+ will be relatively small, resulting in a high-spin configuration.
[Co(en)3]2+
Ethylenediamine molecules (en) are strong field ligands. They have a large spatial extent and strongly interact with the d-orbitals of the metal ion. This leads to a large crystal field splitting, resulting in a low-spin configuration.
Conclusion
Among the given complexes, [CoCl6]4- will have the weakest crystal field splitting. This is because chloride ions are weak field ligands and do not strongly interact with the d-orbitals of the Co2+ ion. As a result, the crystal field splitting will be relatively small, leading to a high-spin configuration.
To make sure you are not studying endlessly, EduRev has designed NEET study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in NEET.