Which of the following is not an organo - metallic compound ?

Options

A. `(C_2H_5)_4Pb`
B. `C_2H_5-O-Na`
C. `C_4H_9Li`
D. `[(C_5H_5)_2Fe]`

Answer

To determine which of the following compounds is not an organometallic compound, we need to understand the definition of organometallic compounds. Organometallic compounds are defined as compounds that contain at least one carbon-metal bond.

Let's analyze the given options step by step:

1. **Tetraethyl Lead (Pb(C2H5)4)**:
- Tetraethyl lead contains lead (Pb), which is a metal, bonded to carbon atoms from the ethyl groups (C2H5).
- There are carbon-lead bonds present.
- Therefore, tetraethyl lead is an organometallic compound.

2. **Sodium Ethoxide (C2H5ONA)**:
- In sodium ethoxide, the ethyl group (C2H5) is bonded to oxygen (O), and sodium (Na) is a metal.
- There is no direct carbon-metal bond present because the carbon is bonded to oxygen, not directly to sodium.
- Therefore, sodium ethoxide is not an organometallic compound.

3. **Butyllithium (C4H9Li)**:
- Butyllithium contains lithium (Li), which is a metal, bonded to the butyl group (C4H9).
- There is a carbon-lithium bond present.
- Therefore, butyllithium is an organometallic compound.

4. **Ferrocene (C10H10Fe)**:
- Ferrocene consists of an iron (Fe) atom sandwiched between two cyclopentadienyl anions (C5H5).
- There are carbon-iron bonds present.
- Therefore, ferrocene is an organometallic compound.

After analyzing all the options, we conclude that the compound that is not an organometallic compound is **Sodium Ethoxide (C2H5ONA)**.

### Final Answer:
**Sodium Ethoxide (C2H5ONA) is not an organometallic compound.**