Which of the following is not a resonance structure of the others ?

Options

A.
B.
C.
D.

Explanation

To determine which structure is not a resonance structure of the others, we will analyze the given structures one by one. Resonance structures are different ways of drawing the same molecule, where the arrangement of electrons differs, but the arrangement of atoms remains the same.

### Step-by-Step Solution:

1. **Identify the Structures**:
- First, we need to look at the structures provided in the question. Let's denote them as A, B, C, and D for simplicity.

2. **Analyze Resonance Structures**:
- **Structure A**: Check if you can move electrons (double bonds or lone pairs) to create a new structure that still maintains the same atoms.
- **Structure B**: Repeat the process. If you can shift electrons to form a new structure without changing the arrangement of atoms, it is a resonance structure.
- **Structure C**: Again, check for the possibility of moving electrons to create a new valid structure.
- **Structure D**: Analyze this structure carefully. If you find that moving electrons does not yield a structure that maintains the same atoms or leads to a significant change in charge distribution, it may not be a resonance structure.

3. **Compare the Structures**:
- After analyzing all four structures, compare them. The structures that can be transformed into one another by moving electrons are resonance structures.
- Look for the structure that does not fit this criterion.

4. **Conclusion**:
- Based on the analysis, if Structure D shows a significant difference in charge distribution or cannot be transformed into the other structures by simple electron movement, then Structure D is not a resonance structure of the others.

5. **Final Answer**:
- Therefore, the structure that is not a resonance structure of the others is **D**.