Name any one solid in which both Frenkel and Schottky defects occur.

Explanation

To solve the question, "Name any one solid in which both Frenkel and Schottky defects occur," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Defects**:
- **Frenkel Defect**: This defect occurs when a cation (or anion) leaves its lattice position and occupies an interstitial site. This typically happens in solids where there is a significant size difference between the cation and anion. The density of the solid remains the same because the total number of ions does not change.
- **Schottky Defect**: This defect occurs when an equal number of cations and anions are missing from the lattice, creating vacancies. This leads to a decrease in density since there are fewer ions in the lattice.

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