Question

What is the coordination number of Fe in the complex \([Fe(C_2O_4)_3]^{3-}\)?

• A. 3
• B. 4
• C. 6
• D. 9

Hint:

Coordination number = number of donor atoms attached to the central metal atom. For bidentate ligands, multiply the number of ligands by \(2\).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the coordination number of the central metal ion (Iron, \(Fe\)) within a specific coordination complex.
Step 2: Key Formula or Approach:
The coordination number is defined as the total number of coordinate covalent bonds formed between the central metal ion and its surrounding ligands.
It is calculated as the number of ligands multiplied by the denticity (number of donor atoms per ligand) of those ligands.
Step 3: Detailed Solution:
First, identify the ligand present in the complex \([Fe(C_2O_4)_3]^{3-}\).
The ligand is the oxalate ion (\(C_2O_4^{2-}\)).
The oxalate ion is a well-known bidentate ligand, meaning each single oxalate ion donates two pairs of electrons through its two oxygen atoms.
Next, count the number of ligands present:
There are \(3\) oxalate ligands attached to the iron atom.
Now, calculate the total coordination number:
\[ \text{Coordination Number} = (\text{Number of ligands}) \times (\text{Denticity}) \] \[ \text{Coordination Number} = 3 \times 2 = 6 \] Step 4: Final Answer:
The coordination number of Fe is \(6\).