Question

Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereo – chemistry and magnetic moment of the complex. 

1. K[Cr(H₂O)₂(C₂O4)₂]. 3H₂O 

2. [CO(NH₃)₅Cl]Cl₂ 

3. CrCl₃(py)₃ 

4. Cs[FeCl₄] 

5. K₄[Min(CN)₆]

Answer 1

1. Potassium diaquabis (oxalato) chromate (III) trihydrate. 

Cordination no. = 6 

Shape = Octahedral 

Oxidation state of Cr = x + 0 + 2 (-2) = -1 

(or) 

x – 4 = – 1 

(or)

x = + 3 

Electronic configuration of Cr³⁺ = 3d³ = t_2g ³e_g⁰ 

No. of unpaired electrons (n) = 3 

Magnetic moment (µ) = g\(\sqrt{n(n+2)}\) = g\(\sqrt{3(5)}\) = g\(\sqrt{15}\) BM = 3.87BM

2. Pentaamminechloro cobalt (III) chloride Cordination no. of CO = 6 

Shape = Octahedral Oxidation state of CO = x + 0 -1 = +2 

(or) 

x = +3 

Electronic configuration of CO³⁺ = 3d⁶ = t_2g ⁶e_g⁰ 

n = 0 

Magnetic moment (p) = 0 

3. Trichlorotripyridine chromium (III), Cordination no, of Cr = 6 

Shape = Octahedral Oxidation state of Cr = x – 3 + 0 = 0 

x = +3 

Electronic configuration of Cr³⁺ = 3d³ = t_2g ³e_g⁰ 

n = 3

Magnetic moment (µ) = g\(\sqrt{n(n+2)}\) = g\(\sqrt{3(5)}\) = g\(\sqrt{15}\) BM = 3.87BM

4. Caesium tetrachloroferrate (III), Cordination no. of Fe = 4 

Shape = Tetrahedral Oxidation state of Fe = x – 4 = -1 x = + 3 

Electronic configuration of Fe³⁺ = 3d⁵ = e²t₂³

n = 5 

(µ) =  g\(\sqrt{5(5+2)}\) = g\(\sqrt{3(5)}\) = 5.92 BM

5. Potassium hexacyanomanganate (II), Cordination no. of Mn = 6 

Shape = Octahedral Oxidation state of Mn = x – 6 = -4 x = +2 

Electronic configuration of Mn²⁺ = 3d⁵ = t_2g ⁵e_g⁰ 

n =1 

(µ) = g\(\sqrt{1(1+2)}\)= g\(\sqrt{3}\) BM = 1.73 BM