Question

Give the coordination number of the central metal ion in the following complex ions.

Answer 1

Answer:

a). Coordination no. of $[Ni(en)_2(NH_3)_2]^2+$ = 6

b). Coordination no. of $[Fe(en)(ox)Cl_2]^2-$ = 6

Explanation:

Coordination number is defined as number of donar atoms bonded to the central atom of the complex ion.

a). Coordination no. of $[Ni(en)_2(NH_3)_2]^2+$ = 6

en or ethylenediamine is a bidentate ligand.

In bidentate ligand, two atoms directly bonded to the central atom.

NH3 is a unidentate ligand.

So, coordination no.= No. of bidentate ligand x 2 + No. of unidentate ligand

                                = $2\times 2 + 2 = 6$

b). Coordination no. of $[Fe(en)(ox)Cl_2]^2-$ = 6

Ethylenediamine (en) is a bidentate ligand.

oxalate ion (ox) is also a bidentate ligand.

Cl is a unidentate ligand

So, coordination no.= No. of bidentate ligand x 2 + No. of unidentate ligand

                                = $2\times 2 + 2 = 6$