Which of the following molecules does not show any resonating structures?

Options

A. `NH_(3)`
B. `CO_(3)^(2-)`
C. `O_(3)`
D. `SO_(3)`

Explanation

To determine which of the following molecules does not show any resonating structures, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Resonating Structures**:
Resonating structures occur when there are multiple valid Lewis structures for a molecule that differ only in the arrangement of electrons. This typically involves the movement of pi electrons or lone pairs to form different structures.

2. **Analyzing Option A: Ammonia (NH3)**:
- Ammonia has the structure: H-N-H with a lone pair on nitrogen.
- There are no pi bonds or conjugated systems present in NH3.
- Since there are no alternate positions for electrons to move into, NH3 does not have any resonating structures.

3. **Analyzing Option B: Carbonyl (C=O)**:
- The carbonyl group (C=O) can participate in resonance.
- The lone pair on oxygen can be delocalized to form a double bond with carbon, while the pi bond can shift to oxygen.
- Therefore, C=O does show resonating structures.

4. **Analyzing Option C: Ozone (O3)**:
- Ozone has a structure where one of the oxygen atoms has a double bond with another oxygen and a single bond with the third oxygen.
- The lone pairs on the oxygen atoms can be rearranged, allowing for resonance.
- Thus, ozone does exhibit resonating structures.

5. **Analyzing Option D: Sulfur Trioxide (SO3)**:
- SO3 has a structure where sulfur is bonded to three oxygen atoms, with double bonds present.
- The pi electrons can be delocalized among the oxygen atoms, allowing for resonance.
- Therefore, SO3 also shows resonating structures.

6. **Conclusion**:
Based on the analysis, the molecule that does not show any resonating structures is **Option A: Ammonia (NH3)**.

### Final Answer:
**Ammonia (NH3) does not show any resonating structures.**