Stoichiometric defect is also known as

Options

A. Intrinsic defect
B. Impurity defect
C. Thermodynamic defect
D. Both (1) & (3)

Answer

### Step-by-Step Solution

1. **Understanding Stoichiometric Defects**:
- Stoichiometric defects are types of defects in a crystal lattice where the stoichiometry (the ratio of the elements in a compound) remains unchanged. This means that while there may be some missing ions or atoms, the overall ratio of the different types of ions in the compound does not change.

2. **Identifying the Other Types of Defects**:
- There are various types of defects in solids, including:
- **Thermodynamic Defects**: These occur due to thermal agitation, where ions may vacate their lattice positions as temperature increases.
- **Impurity Defects**: These occur when foreign atoms or ions are introduced into the lattice, altering the composition.
- **Stretching Defects**: This term is less commonly used and may refer to defects caused by the presence of impurities or distortions in the lattice.

3. **Conclusion**:
- The question asks for another name for stoichiometric defects. The term "stoichiometric defect" is often referred to as "vacancy defect" because it involves the absence of ions from their lattice positions without changing the overall stoichiometry of the material.

### Final Answer:
Stoichiometric defect is also known as **vacancy defect**.

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