Which one of the following complex has the highest magnitude of Crystal Field Splitting Energy `(Delta_0)` ?

Options

A. `[Co(H_(2)O)_(6)]^(3+)`
B. `[Co (NH_(3))_(6)]^(3+)`
C. `[Co(C_(2)O_(4))_(3)]^(3-)`
D. `[CoF_(6)]^(3-)`

Answer

B

Explanation

The crystal field splitting, i.e., `Delta_(0)`, depends upon the field produced by the ligand and charge on the metal ion.
So, ligands can be arranged in a series in the order of increasing field strength. This series is known as spectrochemical series.
e.g., `I^(Θ) lt Br^(Θ) lt SCN^(Θ) lt Cl^(Θ) lt F^(Θ) lt OH^(Θ) lt C_(2)O_(4)^(2-) lt H_(2)O lt NCS^(Θ) lt EDTA^(4-) lt NH_(3) lt en lt CN^(Θ) lt CO :'`
Among the given options, ligand `(NH_(3))` has highest magnetic field therefore, it has maximum value for `Delta_(0)`. Hence option (b) is the correct answer.