Study the colour and magnetic properties of coordination compounds. Includes practice questions to test your understanding of these key concepts in coordination chemistry.
[Co(en)3]3+ contains 3 ethane-1,2-diamine (en) ligands, a bidentate ligand denoted as H₂NCH₂CH₂NH₂.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
In [Co(en)2Cl₂]NO₃, [Co(en)2Cl₂]+ balances NO₃−. Each en is neutral, each Cl− is −1. Thus, x + 0 + 2(−1) = +1, so x = +3.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
[Mn(H₂O)6]2+ (Mn₂+, d5) with weak field H₂O is high spin (t2g3 eg2), 5 unpaired electrons, matching a free d5 ion’s magnetic moment.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Fe₃+ (d5) in [Fe(H₂O)6]3+ (octahedral) with weak field H₂O is high spin (5 unpaired electrons). Magnetic moment = √[5(5+2)] = √35 ≈ 5.92 BM.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Coordination number = 6 (6 H₂O), counter ions = 3 (3 Cl−). Difference = 6 − 3 = 3.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
[Ni(H₂O)6]2+ (Ni₂+, d8) is colored (green) due to d-d transitions with weak field H₂O. With strong field CN− (e.g., [Ni(CN)6]4−), it becomes low spin (diamagnetic), no d-d transitions, colorless.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Fe₃+ (d5) in [FeF₆]3− (octahedral) with weak field F− is high spin (5 unpaired electrons). Magnetic moment = √[5(5+2)] = √35 ≈ 5.92 BM.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
[CoCl₄]2− (Co₂+, d7) with weak field Cl− is tetrahedral and high spin (3 unpaired electrons), making it paramagnetic.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Cr is in 0 oxidation state with 6 CO ligands. EAN = 24 − 0 + 2 × 6 = 36.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Ni₂+ (d8) in a tetrahedral field (e.g., [NiCl₄]2−) with weak field Cl− has e4 t24, 2 unpaired electrons, making it paramagnetic.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
[Fe(CN)6]4− (Fe₂+, d6) with strong field CN− is low spin (t2g6), 0 unpaired electrons. [Co(H₂O)6]3+ (Co₃+, d6) with weaker H₂O is high spin, but [Fe(H₂O)6]2+ fits better contextually.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
Ni₂+ (d8) in [Ni(H₂O)6]2+ (octahedral) with weak field H₂O is high spin (t2g6 eg2), 2 unpaired electrons. Magnetic moment = √[2(2+2)] = √8 ≈ 2.83 BM.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Colour and Magnetic Properties and Stability and Importance
