Question

1. How can the character and the reactivity of a ligand be affected by complexation?

2. Discuss trends in metal complexes based on the position of the metal element in the same row of the periodic table, and in the same column but different rows.

Answer 1

1. The ligand which can donate electrons for sigma bond with metal and which can accept electro pair for pi bonding can form more stable complexes.

Simply sigma donor and pi acceptor ligands can form strong complexes with metals.

Example CO and CN^-

2. Generally transition metals and metal ions form complexes with ligands.

From left to right in a row stability of complexes increases.

In the same column stability of complexes increases. But 4d and 5d row transition metals form complexes with coordination number four where as 3d transition metals form complexes with coordination number six.