Which one of the following is an outer orbital complex and exhibits paramagnetic behaviour ?

Options

A. (a) `[Cr(NH_3)_6]^(3+)`
B. (b) `[Co(NH_3)_6]^(3+)`
C. (c) `[Ni(NH_3)_6]^(2+)`
D. (d) `[Zn(NH_3)_6]^(2+)`

Answer

C

Explanation

`._(28)Ni^(2+)` in `[Ni(NH_3)_6]^(2+)` has `1s^2, 2s^2 2p^6, 3s^2 3p^6 3d^8` configuration. It uses 4th orbital to show `sp^3d^2`-hybridizaation to form outer complex with 2 unpaired electrons in 3d-orbital.