Which of the following lighands leads to minimum value of `Delta_(@)` ?

Options

A. `NO_(2)^(-)`
B. `CN^(-)`
C. `F^(-)`
D. `OH^(-)`

Answer

C

Explanation

The octahedral crystal field splitting `(Delta_(o))` depends upon the field produced by the lignds and charge on the metal ion. For given metal ion, some ligands are able to produce strong fields in which case the splitting will be larger whereas other produces weak fields and consequently result in small splitting of d orbitals. In general, ligands can be arranged in a series in a series in the order of increasing field strength. A spectrochemical series, is a list of ligands arranged in increasing field strength. A spectrochemical series, is a list of ligands arranged in increasing of their abilities to split the d orbital energies. `I^(-) lt Br^(-) lt C1^(-) lt F^(-) lt OH^(-) lt H_(2)O lt NH_(3) lt en lt NO_(2)^(-) lt CN^(-) lt CO` Note that the order in the spectrochemical series is the same regardless of what metal atom (or ion) is present. `NO_(2)^(-)` , `CN^(-)` and CO are strong called strong field ligands, because they cause a large splitting of the d orbital energy levels. On the other hand, the halide ions and hydroxide ion are week field ligands because they split the d orbitals to a lesser extent.