In the complex `Fe(CO)_(x)`, the value of x is if its EAN is 36.

Explanation

To solve the problem of determining the value of \( x \) in the complex \( \text{Fe(CO)}_x \) given that its Effective Atomic Number (EAN) is 36, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number of Iron**:
- The atomic number of iron (Fe) is 26.

2. **Determine the Oxidation State of Iron**:
- In the complex \( \text{Fe(CO)}_x \), carbon monoxide (CO) is a neutral ligand. Therefore, the oxidation state of iron in this complex is 0.

3. **Use the EAN Formula**:
- The formula for calculating the Effective Atomic Number (EAN) is:
\[ \text{EAN} = \text{Atomic Number of Central Atom} + \text{Oxidation State} + \text{Electrons Donated by Ligands} \]
- Substituting the known values:
\[ \text{EAN} = 26 + 0 + \text{Electrons Donated by Ligands} \]

4. **Calculate Electrons Donated by Ligands**:
- Each CO ligand donates 2 electrons. If there are \( x \) CO ligands, the total number of electrons donated is \( 2x \).
- Thus, we can rewrite the EAN equation as:
\[ \text{EAN} = 26 + 0 + 2x = 26 + 2x \]

5. **Set the EAN Equal to 36**:
- According to the problem, the EAN is 36. Therefore, we set up the equation:
\[ 26 + 2x = 36 \]

6. **Solve for \( x \)**:
- Rearranging the equation gives:
\[ 2x = 36 - 26 \]
\[ 2x = 10 \]
\[ x = \frac{10}{2} = 5 \]

7. **Conclusion**:
- The value of \( x \) in the complex \( \text{Fe(CO)}_x \) is 5.

### Final Answer:
The value of \( x \) is 5.