The crystal showing Frenkel defect is :

Options

A.
B.
C.
D.

Answer

To determine which crystal shows a Frenkel defect, we need to understand what a Frenkel defect is and how it manifests in a crystal structure.

### Step-by-Step Solution:

1. **Definition of Frenkel Defect**:
- A Frenkel defect occurs when an atom or ion is displaced from its normal lattice position to an interstitial site, creating a vacancy at the original site and an interstitial defect where the atom is now located.

2. **Understanding the Crystal Structure**:
- In a crystal lattice, atoms are arranged in a specific pattern. A Frenkel defect involves the movement of an atom from its original position to a space that is not normally occupied (interstitial site).

3. **Identifying Suitable Crystals**:
- Frenkel defects are commonly found in ionic crystals, particularly those with smaller cations and larger anions. Examples include silver halides (like AgBr, AgCl) and some alkali metal halides.

4. **Analyzing the Options**:
- If provided with options, we need to look for a crystal that allows for the displacement of an ion to an interstitial site while maintaining the overall structure.

5. **Conclusion**:
- Based on the characteristics of Frenkel defects, the correct answer would be the crystal that allows for such dislocation and presence of interstitial atoms.

### Final Answer:
- The crystal showing a Frenkel defect is typically **AgBr (Silver Bromide)** or similar ionic compounds.