The magnitude of `Delta_(0)` will be highest in which of the following complex.

Options

A. `[Cr (CN _(6)) ] ^(3-)`
B. `[ Cr ( H _(2) O ) _(6) ] ^(3-)`
C. `[Cr ( NH _(3)) _(6) ] ^(3+)`
D. `[Cr ( C _(2) O _(4)) _(3) ] ^(3-)`

Answer

A

Explanation

The crystal field splitting, `Delta _(0)` depends upon the field produced by the ligand and change on the metal ion. In all these complexes of chromium, charge acquired by metal ion is +3. Therefore `Delta _(0)` depends upon the field produced by the ligand. In accordance with the spectrochemical series, the increasing order of field strength is `C _(2) O _(4) ^( 2-) lt H _(2) O lt NH _(3) lt CN ^(-)`
Thus,` CN ^(-)` is the strong field ligand and will produce highest magnitude of `Delta _(0).`