Problems 

Problems Based on Coordination Chemistry

Q1: Provide the formulas for the following coordination compounds.

(i) Hexaamminecobalt(II) chloride

(ii) Potassium trioxalatoferrate(III)

(iii) μ-Dihydroxido-bis{tetramminecobalt(III)} nitrate

(iv) Pentaammine(nitrito-кO) cobalt (III) chloride

(v) Dichlorido-bis-(ethane-1,2-diamine) rhodium (III) ion

(vi) Diamminediiodidocobaltate(III) ion

(vii) Potassium tetracyanidonickelate(II)

(viii) Potassium diaminetetrachloridochromate(III)

(ix) Hexaaminecobalt(III) hexacyanidochromate(III)

(x) Dibromido-bis-(ethane-1,2-diamine) cobalt (III) nitrate

Q 2: Determine the coordination numbers and write the chemical formulas for each of the following compounds, including all possible isomers where applicable

(a) tetrahydroxidozincate(II) ion;

 (b) hexacyanidopalladate(IV) ion;                        

(c) dichloridoaurate(I) ion (note that aurum is Latin for “gold”);                       

 (d) diamminedichloroplatinum(II);

 (e) potassium diamminetetrachloridochromate(III);

(f) hexaamminecobalt(III) hexacyanidochromate(III);

 (g) dibromide-bis-(ethane-1,2-diamine) cobalt(III) nitrate

Q 3: Identify the coordination number and calculate the  Effective Atomic Number (EAN) of the central metal atom in each of the following coordination compounds.

 (a) [Pt(H2O)2Br2];

 (b) [Pt(NH3)(py)(Cl)(Br)] (py = pyridine);                                 

 (c) [Zn(NH3)2Cl2];

 (d) [Zn(NH3)(py)(Cl)(Br)];

 (e) [Ni(H2O)4Cl2];                            

(f) [Fe(en)2(CN)2]+ (en = ethylenediamine, C2H8N2)

Q 4: Identify the types of isomerism in the following
    (a) [Co (NH3)4Cl2] +

    (b) [Cr(en)3]3+

    (c) [Co (NH3)5(NO2)]2+

    (d) [Co (NH3)5Br]SO4

    (e) [Co (NH3)6] [Cr (CN)6]

Q 5: Calculate the spin-only magnetic moment of the complex [Fe(H2O)6]2+ and determine whether it is paramagnetic or diamagnetic.

 Q 6: Determine whether the complex [Fe(CN)6]4− is a high- or low-spin complex. Justify your answer based on crystal field theory and calculate the number of unpaired electrons.

Q7: Compare the magnetic behaviour of [CoF6]3− and [Co(NH3)6]3+. Explain how the nature of ligands affects the number of unpaired electrons and magnetic moment.

Q8:  Write the electronic configuration of the central metal ion in the complex [Ni (CN)4]2− and predict whether the complex is paramagnetic or diamagnetic.

Q9: A coordination complex exhibits a magnetic moment corresponding to two unpaired electrons. Propose a possible formula for this cobalt complex and explain the reasoning behind your answer.