What is the coordination number of the central metal ion in the complex [Co(en)3]3+?

💡 Solution & Explanation

The coordination number represents the total number of ligand donor atoms bonded directly to the central metal ion. In the complex ion [Co(en)3]3+, ethylenediamine acts as a bidentate ligand, meaning each molecule donates two electron pairs. With three ethylenediamine molecules coordinated to the cobalt ion, the overall coordination number equals 3 multiplied by 2, which gives 6.