Indicate the coordination number for the central metal atom in each of the following coordination compounds:

(a) [Pt (H2O) 2Br2]

(b) [Pt (NH3) (py) (Cl) (Br) ] (py = pyridine, C5H5N)

(c) [Zn (NH3) 2Cl2]

(d) [Zn (NH3) (py) (Cl) (Br) ]

(e) [Ni (H2O) 4Cl2]

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

Answer: A. 4, since all 4 ligands (2 H2O&2Br) are monodentate hence 4x1=4

B. 4, (4x1=4)

C. 4 (4x1=4)

D. 4 (4x1=4)

E. 6 (6x1=6)

F. 6 (2 (2) + 2 (1) = 4+2=6) en is bidentate ligand

Explanation:

Coordination number is equal to number of ligands surrounded the metal atom.

Coordination number = No of ligands X denticity

Denticity is nothing but nature of ligands like mono, bi dentate, or tetrads rate etc.