Select the correct statement for CsCI crystal :-

Options

A. `Cs^(+)` forms simple cubic lattice, `CI^(-)` forms simple cubic lattice
B. `CI^(-)` occupies the body center of `Cs^(+)`
C. `Cs^(+)` occupies the body center of `CI^(-)`
D. All are correct

Answer

To solve the question regarding the correct statement for CsCl (Cesium Chloride) crystal, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of CsCl**:
- CsCl crystallizes in a simple cubic structure. In this lattice, the cesium ions (Cs⁺) and chloride ions (Cl⁻) are arranged in a specific manner.

2. **Identify the Coordination Number**:
- In the CsCl structure, each cesium ion is surrounded by 8 chloride ions, and each chloride ion is surrounded by 8 cesium ions. This leads to a coordination number of 8 for both ions.

3. **Analyze the Options**:
- We need to evaluate the given statements about the CsCl crystal structure.
- **Option 1**: States that Cs⁺ forms a simple cubic lattice and Cl⁻ also forms a simple cubic lattice. This is true.
- **Option 2**: States that the chloride ion occupies the body center of the cesium ion. This is also true.
- **Option 3**: States that the cesium ion occupies the body center of the chloride ion. This is also true.
- **Option 4**: States that all the above statements are correct.

4. **Conclusion**:
- Since all the statements regarding the CsCl crystal structure are true, we conclude that the correct answer is **Option 4**, which states that all the statements are correct.

### Final Answer:
The correct statement for CsCl crystal is **Option 4**: All statements are true.