The d-electron.configurations of `Mn^(2+), Fe^(2+),Co^(3+)` and `Ni^(2+)` are `3d^5, 3d^6, 3d^6, 3d^8` respectively. Which of the following aqua complexes will exhibit the minimum paramagnetic behaviour?

Options

A. `[Fe(H_2O)_6]^(2+)`
B. `[Co(H_2O)_6]^(3+)`
C. `[Mn(H_2O)_6]^(2+)`
D. `[Ni (H_2O)_6]^(2+)`

Answer

B

Explanation

`[Co(H_2O)_6]^(3+) = d^2 sp^3`, low spin, diamagnetic, magnetic moment = zero BM