In which of the following coordination entites the magnitude of `Delta_(0)` (CFSE in octehedral field) will be maximum.
`(At. No .Co = 27)`

Options

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

Answer

C

Explanation

As in all the given complex the central metal atom is same and contains same number of d electrons, thus CFSE is decided by ligands. In case of strong field ligand, CFSE is maximum. `CN^(-)` is a strong field ligand, Hence, in `[Co(CN)_(6)]^(3-)` magnitude of CFSE i.e. `Delta_(0)` is maximum.