The arrangement of`CI^(-)` ions in `CsCI` structure is

Options

A. hcp
B. fcc
C. bcc
D. Simple cubic

Answer

To determine the arrangement of \( \text{Cl}^- \) ions in the \( \text{CsCl} \) structure, we need to analyze the crystal structure of cesium chloride. Here’s a step-by-step solution:

### Step 1: Identify the Crystal Structure
The \( \text{CsCl} \) structure is known to have a body-centered cubic (BCC) arrangement.

### Step 2: Visualize the Unit Cell
In a BCC unit cell, there are atoms located at the corners of the cube and one atom at the center of the cube.

### Step 3: Count the Corner Atoms
In the BCC structure of \( \text{CsCl} \):
- There are 8 corners in the cube.
- Each corner atom contributes \( \frac{1}{8} \) of an atom to the unit cell.

Thus, the total contribution from the corner chloride ions is:
\[ 8 \text{ corners} \times \frac{1}{8} = 1 \text{ Cl}^- \text{ ion} \]

### Step 4: Identify the Center Atom
In the center of the BCC unit cell, there is one \( \text{Cs}^+ \) ion.

### Step 5: Total Number of Ions in the Unit Cell
Now, we can summarize the total number of ions in the unit cell:
- \( 1 \text{ Cl}^- \) ion from the corners
- \( 1 \text{ Cs}^+ \) ion at the center

Thus, there are a total of 2 ions in the unit cell.

### Step 6: Arrangement of Ions
In the \( \text{CsCl} \) structure:
- The \( \text{Cl}^- \) ions are located at the corners of the cube.
- The \( \text{Cs}^+ \) ion is located at the center of the cube.

### Conclusion
The arrangement of \( \text{Cl}^- \) ions in the \( \text{CsCl} \) structure is that they occupy the corners of the body-centered cubic unit cell.

### Final Answer
The arrangement of \( \text{Cl}^- \) ions in \( \text{CsCl} \) structure is at the corners of the BCC unit cell.

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