Coordination Compounds · Question 7

Among the following complexes, the total number of diamagnetic species is . [Mn(NH3)6]3+, [MnCl6]3-, [FeF6]3-, [CoF6]3-, [Fe(NH3)6]3+, and [Co(en)3]3+ [Given, atomic number: Mn = 25, Fe = 26, Co = 27; en = H2NCH2CH2NH2]

Answer

1

Solution

[Mn(NH3)6]3+: Mn3+, d4 – even low spin t2g4 has 2 unpaired e⁻ → paramagnetic.

[MnCl6]3-: d4 high spin, 4 unpaired → paramagnetic.

[FeF6]3- and [Fe(NH3)6]3+: d5 – 5 or 1 unpaired → paramagnetic.

[CoF6]3-: d6 high spin (weak field F⁻), 4 unpaired → paramagnetic.

[Co(en)3]3+: d6 low spin t2g6 (strong field en) → diamagnetic.

Answer: 1