Question

What is the coordination number of Cobalt in $[Co(en)_3]^{3+}$?

• A. 3
• B. 4
• C. 6
• D. 2

Hint:

Bidentate ligands like \(en\) contribute two bonds each. Multiply number of ligands by their denticity to find coordination number.

Answer 1

The Correct Option is C

Concept: The coordination number of a complex is the total number of coordinate bonds formed between the central metal atom and the ligands. Ethylenediamine (\(en\)) is a bidentate ligand, meaning each ligand forms two coordinate bonds with the central metal atom.

Step 1: Identify number of ligands and their denticity. Number of ligands \(= 3\), and each ligand forms \(2\) bonds.

Step 2: Calculate coordination number. \[ \text{Coordination number} = 3 \times 2 = 6 \] \[ \boxed{6} \]