Frenkel and Schottky defects are:

Options

A. Nucleus defects
B. Non-crystal defects
C. Crystal defects
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Types of Defects:**
- Frenkel and Schottky defects are types of defects found in crystalline solids. They fall under the category of crystal defects.

2. **Defining Frenkel Defect:**
- The Frenkel defect occurs when a cation (or anion) moves from its normal position in the crystal lattice to an interstitial site, creating a vacancy where it was originally located. This means that there is a dislocation of the particle but it remains within the crystal structure.

3. **Characteristics of Frenkel Defect:**
- In a Frenkel defect, there is no change in the overall density of the crystal because the mass remains the same; a particle has simply moved from one location to another within the crystal.

4. **Defining Schottky Defect:**
- The Schottky defect occurs when an equal number of cations and anions leave the crystal lattice, creating vacancies. This results in a loss of mass and a decrease in density as particles are missing from the lattice.

5. **Characteristics of Schottky Defect:**
- In a Schottky defect, the overall density of the crystal decreases because particles are missing from the lattice structure.

6. **Conclusion:**
- Both Frenkel and Schottky defects are classified as crystal defects. They are important in understanding the properties of ionic solids and their behavior under various conditions.

**Final Answer:**
Frenkel and Schottky defects are classified as **Crystal Defects**.

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