Question

The coordination number of a central metal atom

in a complex is determined by :

• A. the number of ligands around a metal ion bonded by sigma bonds
• B. the number of ligands around a metal ion bonded by $\pi$ -bonds
• C. the number of ligands around a metal ion bounded by sigma and pi bonds both.
• D. the number of only anionic ligands bonded to the metal ion.

Answer 1

The correct option is A the number of ligands around a metal ion bonded by sigma bonds

To determine the coordination number, we count the number of sigma bonds to the metal atom.
Coordination number = the number of ligands around a metal ion bonded by sigma bonds
Pi bonds are not counted for determining the coordination number because 1 sigma bond means 1 ligand