Learn how to name coordination compounds following IUPAC rules, including ligands, central atoms, and oxidation states. Covers common naming conventions and practice problems for exams.
In [Fe(NH₃)4Cl₂]NO₃, [Fe(NH₃)4Cl₂]+ balances NO₃−. Fe is +3, 2 Cl− = −2, 4 NH₃ = 0. Charge = +3 − 2 = +1.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Ligands are named alphabetically: ammine (NH₃), aqua (H₂O), chlorido (Cl). There are 4 NH₃, 1 H₂O, and 1 Cl in the complex. Co’s oxidation state is +3 (since [Co(NH₃)4(H₂O)Cl]2+ balances 2 Cl−). Name: tetraammineaquachloridocobalt(III) chloride.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
[MnCl₄]2− (Mn₂+, d5) in a tetrahedral field with weak field Cl− is high spin (e2 t23), with 5 unpaired electrons.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
In [Ni(NH₃)4]2+, Ni is +2 (oxidation state), and the coordination number is 4. None match here, but [Ni(NH₃)4]2+ fits better conceptually.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Ligands: ammine (NH₃), aqua (H₂O), chlorido (Cl), alphabetically ordered. Co is +3 (balancing 3 Cl−). Name: diamminediaquadichloridocobalt(III) chloride.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
[CoCl₂(en)2]+ has 2 bidentate en (4 donor atoms) and 2 Cl−, totaling 6 ligands. It is octahedral (Co₃+, d6).
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Ligands: ammine (NH₃), nitro (NO₂−), alphabetically ordered. Cr is +3 (balancing 2 Cl− and 1 NO₂−). Name: pentaamminenitrochromium(III) chloride.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
In [Cr(NH₃)4Cl₂]Cl, 1 Cl− outside the coordination sphere is ionizable, forming 1 mole of AgCl.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
[Co(en)2Cl₂]+ (Co₃+, d6) with 2 en and 2 Cl− is octahedral, and the trans isomer has Cl− ligands opposite each other.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Ligands: ammine (NH₃), chlorido (Cl), thiocyanato (SCN), alphabetically ordered. Co is +3 (balancing 2 Cl− and 1 SCN−). Name: tetraamminethiocyanatochloridocobalt(III) chloride.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Co₃+ (d6) in [Co(H₂O)6]3+ (octahedral) with weak field H₂O is high spin: t2g4 eg2, giving 4 unpaired electrons.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
Chelating ligands are polydentate. Oxalate (C₂O₄₂−) is bidentate, forming a 5-membered ring, unlike unidentate ligands like F− or NH₃.
Ref: NCERT Class 12 Chemistry > Chapter 5: Coordination Compounds > Topic: Nomenclature of Coordination Compounds
