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 Similarly, in the complex ions, [Fe(C2O4)3]
3– and
[Co(en)3]
3+, the coordination number of both, Fe and Co, is 6 because
C2O4
2– and en (ethane-1,2-diamine) are didentate ligands 5 2
5