What is the coordination number for each of the following complexes? A) [Fe (gly) 2 (H2O) 2]+B) [Pb (EDTA) ]2-C) [Pt (NH3) 4]2+D) Na[Au (CN) 2]

A) 6

B) 6

C) 4

E) 1

Explanation:

Coordination number, also called Ligancy, the number of atoms, ions, or molecules bound to the metal atom in a complex ion

A) [Fe (gly) 2 (H2O) 2]

Gly = the aminoacid glycin, and works as a bidentate ligand, Bidentate ligands bind through two donor sites. Bidentate means "two-toothed". It can bind to a metal via two donor atoms at once.

This makes the coordination number = 6

B) [Pb (EDTA) ]2

EDTA is a hexadentate ligand and forms very stable complexes.

EDTA forms 6 bonds to the Pb atom (2 Pb-N bonds and 4 Pb-O bonds). The coordination number = 6.

C) [Pt (NH3) 4]2+

It's a squareplanar complex with coordination number = 4 because 4 bindings with NH3

D) Na[Au (CN) 2]

Cyanide binds only to 1 Au - atom. The coordination number = 1