Which one is not an organometallic compound

Options

A. `RMgX`
B. `C_2H_5ONa`
C. `(CH_3)_4Sn`
D. `KC_4H_9`

Explanation

To determine which compound is not an organometallic compound, we first need to understand what an organometallic compound is. Organometallic compounds are defined as compounds that contain at least one bond between a carbon atom of an organic molecule and a metal (which can be a transition metal, main group metal, or even metalloid).

### Step-by-Step Solution:

1. **Identify the Definition**:
- An organometallic compound must contain a metal-carbon bond.

2. **List the Given Compounds**:
- The question provides several compounds: Rmg, C2H5, ONA, CH3, G4, SNK, C4H9.

3. **Analyze Each Compound**:
- **Rmg**: This is likely referring to a compound like RMgX (Grignard reagent), which is organometallic as it contains a carbon-metal bond.
- **C2H5**: This is ethyl, which does not contain a metal, so it is not organometallic.
- **ONA**: This appears to be a representation of a compound that may contain a metal, but without further clarification, it is not clearly organometallic.
- **CH3**: This is methyl, which does not contain a metal, so it is not organometallic.
- **G4**: This is ambiguous without context, but if it refers to a group of atoms without a metal, it is not organometallic.
- **SNK**: Without context, this could refer to a compound that may or may not be organometallic.
- **C4H9**: This is butyl, which does not contain a metal, so it is not organometallic.

4. **Determine Which is Not Organometallic**:
- From the analysis, **C2H5 (ethyl)**, **CH3 (methyl)**, and **C4H9 (butyl)** do not contain metals. Therefore, they are not organometallic compounds.

5. **Final Conclusion**:
- The compound that is definitively not an organometallic compound is **C2H5 (ethyl)**.