Among the following, which is not the `pi`-bonded organometallic compound

Options

A. `K[PtCl_(3)(eta^(2)-C_(2)H_(4))]`
B. `Fe(eta^(5)-C_(5)H_(5))_(2)`
C. `Cr(eta^(6)-C_(6)H_(6))_(2)`
D. `(CH_(3))_(4)Sn`

Explanation

To determine which of the given compounds is not a pi-bonded organometallic compound, we will analyze each option step by step.

### Step 1: Analyze the first compound
- **Compound:** K[PtCl3(C2H4)]
- **Structure:** This compound has potassium (K) as the cation and a platinum complex with three chloride ions and one ethene (C2H4) molecule.
- **Bonding:** The ethene molecule has a double bond (which consists of one sigma and one pi bond). The platinum is bonded to the ethene through the pi bond of the ethene, making this a pi-bonded organometallic compound.

### Step 2: Analyze the second compound
- **Compound:** Fe(C5H5)2
- **Structure:** This compound consists of iron (Fe) and two cyclopentadienyl (C5H5) rings.
- **Bonding:** The cyclopentadienyl rings are bonded to iron through their pi electrons, making this a pi-bonded organometallic compound.

### Step 3: Analyze the third compound
- **Compound:** Cr(C6H6)2
- **Structure:** This compound has chromium (Cr) bonded to two benzene (C6H6) rings.
- **Bonding:** The benzene rings are also bonded to chromium through their pi electrons, classifying this as a pi-bonded organometallic compound.

### Step 4: Analyze the fourth compound
- **Compound:** Sn(CH3)4
- **Structure:** This compound consists of tin (Sn) with four methyl (CH3) groups attached.
- **Bonding:** There are no pi bonds present in this compound; all the bonds are sigma bonds. Therefore, this is not a pi-bonded organometallic compound.

### Conclusion
After analyzing all the options, the compound that is not a pi-bonded organometallic compound is **Sn(CH3)4**.

### Final Answer
The correct answer is **Sn(CH3)4**.

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