Which one is not an organometallic compound ?

Options

A. Ethyl magnesium bromide
B. Tetraethyl lead
C. Sodium ethoxide
D. Trimethyl aluminium

Answer

To determine which of the given options is not an organometallic compound, we need to understand the definition of organometallic compounds. These are compounds in which a carbon atom is directly bonded to a metal atom.

### Step-by-Step Solution:

1. **Understand the Definition**:
Organometallic compounds are characterized by the presence of a direct bond between a carbon atom and a metal atom.

2. **Analyze Each Option**:
- **Option A: Ethyl Magnesium Bromide (C2H5MgBr)**
- Structure: CH3CH2MgBr
- Analysis: In this compound, magnesium (Mg) is directly bonded to a carbon atom (C). Therefore, this is an organometallic compound.

- **Option B: Tetraethyl Lead (Pb(C2H5)4)**
- Structure: CH3CH2Pb(CH2CH3)3
- Analysis: In this compound, lead (Pb) is directly bonded to carbon atoms. Thus, this is also an organometallic compound.

- **Option C: Sodium Ethoxide (C2H5ONa)**
- Structure: CH3CH2O-Na
- Analysis: Here, sodium (Na) is bonded to the oxygen atom (O) of the ethoxide group, not directly to a carbon atom. Therefore, this is NOT an organometallic compound.

- **Option D: Trimethyl Aluminium (Al(CH3)3)**
- Structure: Al(CH3)3
- Analysis: In this compound, aluminium (Al) is directly bonded to carbon atoms. Hence, this is an organometallic compound.

3. **Conclusion**:
Based on the analysis, the compound that is not an organometallic compound is **Sodium Ethoxide (Option C)**.

### Final Answer:
**C. Sodium Ethoxide is not an organometallic compound.**