What is point defect?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Point Defect**:
- A point defect refers to irregularities or deviations from the ideal arrangement of atoms in a crystalline solid. These defects occur at a single point or atom within the crystal lattice.

2. **Types of Point Defects**:
- Point defects can be classified into three main types:
1. **Stoichiometric Defect**:
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