In a solid lattice the cation has left a lattice sirte and is located at an interstital position , the lattice defect is

Options

A. Interstitial defect
B. Schottky defect
C. Valency defect
D. Frenkel defect

Answer

To solve the question regarding the type of lattice defect when a cation leaves its lattice site and occupies an interstitial position, we can analyze the different types of defects in solid lattices. Here’s a step-by-step solution:

### Step 1: Understand the Types of Lattice Defects
Lattice defects can be classified into several categories:
1. **Interstitial Defect**: This occurs when atoms or ions occupy the interstitial spaces (vacant spaces) in the lattice.
2. **Schottky Defect**: This defect arises when there are vacancies created by the absence of ions or atoms from their lattice sites.
3. **Valency Defect**: This defect involves changes in the valency of ions, often leading to vacancies in the lattice.
4. **Frenkel Defect**: This defect occurs when an ion leaves its normal lattice position and occupies an interstitial site.

### Step 2: Analyze the Given Situation
The question states that a cation has left its lattice site and is now located at an interstitial position. This means that:
- The cation is no longer at its original position (which indicates a vacancy).
- The cation has moved to an interstitial site (which indicates it is occupying a space that is normally unoccupied).

### Step 3: Identify the Correct Type of Defect
From the definitions:
- The **Frenkel defect** is specifically characterized by an ion (in this case, a cation) leaving its normal lattice site and moving to an interstitial site.
- The **Schottky defect** involves missing ions creating vacancies but does not involve ions moving to interstitial sites.

### Conclusion
Since the cation has left its lattice site and is now in an interstitial position, this corresponds to a **Frenkel defect**.

### Final Answer
The lattice defect described in the question is a **Frenkel defect**.

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