Question

For the complex

[Fe(en)₂Cl₂]Cl (en = ethylene diamine), identify The complex is [Fe(en)₂Cl₂]Cl.

(i) The oxidation number of Fe.

(ii) The hybrid orbital and shape of the complex.

(iii) The magnetic behaviour of the complex.

(iv) The number of geometrical isomers.

(v) Whether there is an optical isomer also.

(vi) The name of the complex (At. No of Fe 26)

Answer 1

(i) Oxidation number of Fe

= x + 2 x 0 + 2(-1)

= +1

x – 2 = +1

⇒ x = 3

(ii) Orbitals in Fe⁺³(d⁵)

In the presence of a strong ligand (en), the electrons in 3d orbital get paired.
Fe⁺³ excited state

Thus, Fe⁺³ ion undergoes d²sp³ hybridisation therefore the shape is octahedral.

(iii) The complex is paramagnetic due to the presence of one unpaired electron.

(iv) It exhibits cis-trans isomerism

(v) Cis isomer will show optical isomerism.

(vi) Dichlorido bis(ethane 1, 2, diamine) iron, (III) chloride.