NO2
– ion can coordinate either through
nitrogen or through oxygen to a central metal
atom/ion Similarly, SCN
– ion can coordinate through the
sulphur or nitrogen atom ( d ) Coordination number
The coordination number (CN) of a metal ion in a complex can be
defined as the number of ligand donor atoms to which the metal is
directly bonded For example, in the complex ions, [PtCl6]
2– and
[Ni(NH3)4]
2+, the coordination number of Pt and Ni are 6 and 4
respectively