Select the diamagnetic complex ion amongst the following complexes (At no. : Fe= 26,Co=27 )

Options

A. `K_(3) [Fe (CN)_(6) ]`
B. `[Co(NH_(3))_(6)]Cl_(3)`
C. `K_(3)) [FeF_(6)]`
D. `K_(3) [CoF_(6)]`

Answer

B

Explanation

Coordination compound/ion having unpaired electron is paramagnetic in nature while if it has all the electrons paired , it is diamagnetic .
`[Co (NH_(3))_(6)i.e., [Co(NH_(3))_(6)]^(3+)ion`
` ""_(27)Co=[Ar]3d^(7) 4S^(2)`
`implies Co ^(3+)=[Ar]3d^(6) 4s^(0)`

therefore , `[Co(NH_(3))_(6)]Cl_(3) ` is diamagnetic in nature .