Which of the following is the correct order of stability of allotropes of carbon?

Options

A. `"Diamond" lt" graphite"lt"fullerene"`
B. `"Fullerene"lt"graphite"lt"diamond"`
C. `"Graphite"lt"fullerene"lt"diamond"`
D. `"Fullerene"lt"diamond"lt"graphite"`

Answer

To determine the correct order of stability of the allotropes of carbon, we need to analyze the stability of each allotrope based on their structures and properties. The allotropes of carbon we will consider are diamond, graphite, and fullerene.

### Step-by-Step Solution:

1. **Understanding Allotropes of Carbon**:
- Carbon exists in several allotropes, the most common being diamond, graphite, and fullerene (C60).
- Each allotrope has a distinct structure and bonding characteristics which influence its stability.

2. **Analyzing Diamond**:
- Diamond has a tetrahedral structure where each carbon atom is bonded to four other carbon atoms through strong covalent bonds.
- This structure makes diamond extremely hard but does not necessarily make it the most stable allotrope in terms of energy.

3. **Analyzing Graphite**:
- Graphite consists of layers of carbon atoms arranged in a hexagonal lattice. The layers are held together by weak van der Waals forces.
- Graphite is known to be thermodynamically stable due to its lower enthalpy of formation compared to diamond.

4. **Analyzing Fullerene**:
- Fullerene, specifically C60, has a spherical structure that is highly strained.
- The strain in the structure makes fullerene less stable than both diamond and graphite.

5. **Comparing Stability**:
- Stability of an allotrope can be assessed by its enthalpy of formation. The more negative the enthalpy change (ΔH), the more stable the allotrope.
- Graphite has the most negative ΔH, indicating it is the most stable allotrope.
- Diamond has a less negative ΔH than graphite, making it the second most stable.
- Fullerene has the least negative ΔH, indicating it is the least stable allotrope.

6. **Conclusion**:
- Based on the analysis, the correct order of stability of the allotropes of carbon is:
- **Graphite > Diamond > Fullerene**

### Final Answer:
The correct order of stability of allotropes of carbon is:
**Graphite > Diamond > Fullerene**