In a solid lattice the cation and anion both have left a lattive site. The lattice defect is known as

Options

A. intestitial defect
B. vancancy defect
C. Frenkel defect
D. schottky defect

Answer

To solve the question regarding the type of lattice defect that occurs when both cation and anion leave their lattice sites, we can analyze the options provided and determine the correct answer step by step.

### Step 1: Understand the Types of Lattice Defects
Lattice defects in solids can be classified into several types, including:
- Interstitial defects
- Vacancy defects
- Frenkel defects
- Schottky defects

### Step 2: Analyze Each Option
1. **Interstitial Defect**: This defect occurs when some particles occupy vacant interstitial positions within the lattice. Since the question specifies that both cation and anion have left their lattice sites, this option is not correct.

2. **Vacancy Defect**: This defect arises when some lattice sites are vacant, meaning that some ions are missing from their positions. However, it does not specify that both cation and anion are missing, so this option is also not correct.

3. **Frenkel Defect**: This defect occurs when an ion is missing from its normal position and occupies an interstitial site. In this case, only one type of ion is displaced, so this option does not apply to the question.

4. **Schottky Defect**: This defect arises when both cation and anion are missing from their normal lattice sites. This matches the condition described in the question, where both ions have left their lattice sites.

### Step 3: Conclusion
Based on the analysis of the options, the correct answer to the question is **Schottky defect**. This defect is characterized by the absence of both cations and anions from their respective lattice sites.

### Final Answer
The lattice defect is known as **Schottky defect**.

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