Which of the following is not an electrophile ?

Options

A. `SO_(3)`
B. `overset(+)CH_(3)`
C. `CH_(3)overset(+)CO`
D. `(CH_(3))_(2)NH`

Explanation

To determine which of the following compounds is not an electrophile, we need to understand the characteristics of electrophiles. An electrophile is a species that is electron-deficient and can accept electrons. This typically includes compounds with incomplete octets, positive charges, or vacant d-orbitals.

Let's analyze each option provided:

1. **SO3 (Sulfur Trioxide)**:
- SO3 has a sulfur atom that can utilize its vacant d-orbitals to accept electrons. Therefore, SO3 is an electrophile.

2. **CS3+ (Methyl Cation)**:
- The CS3+ species has a positive charge, indicating it is electron-deficient. This makes it an electrophile.

3. **CS3CO+ (Acetyl Cation)**:
- Similar to the methyl cation, the acetyl cation (CS3CO+) also has a positive charge, making it electron-deficient and thus an electrophile.

4. **CS3NHCS3 (Dimethylamine)**:
- In this compound, the nitrogen atom has a lone pair of electrons. This makes the compound electron-rich, allowing it to donate electrons rather than accept them. Therefore, CS3NHCS3 behaves as a nucleophile.

Based on this analysis, the compound that is not an electrophile is **CS3NHCS3**.

### Final Answer:
The compound that is not an electrophile is **CS3NHCS3**.