Question

Give the electronic configuration of the following complexes on the basis of crystal field splitting theory. `[CoF_(6)]^(3-), [Fe(CN)_(6)]^(4-)` and `[Cu(NH_(3))_(6)]^(2+)`.

Answer 1

According to spectrochemical series, ligands can be arranged in a series in the order of increasing field strength i.e., `F^(-) lt NH_(3) lt CN^(-)`.
Hence, `CN^(-)` and `NH_(3)` being strong field ligand pair up the `t_(2g)` electrons before filling `e_(g)` set. `[CoF_(6)]^(3-), Co^(3+)=(d^(6))t_(2g)^(4)e_(g)^(2)`