In a body centred cubic cell an atom at the body of centre is shared by-

Options

A. 1 unit cell
B. 4 unit cells
C. 3 unit cells
D. 2 unit cells

Answer

To solve the question regarding how many unit cells share the atom located at the body center of a body-centered cubic (BCC) cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of BCC**:
- In a body-centered cubic (BCC) unit cell, there are atoms located at each of the eight corners of the cube and one atom at the center of the cube.

2. **Determine Atom Contribution at Corners**:
- Each corner atom is shared among eight adjacent unit cells. Therefore, the contribution of each corner atom to a single unit cell is \( \frac{1}{8} \).

3. **Focus on the Body-Centered Atom**:
- The atom located at the center of the BCC unit cell is not shared with any other unit cell. It is entirely contained within that specific unit cell.

4. **Conclusion**:
- Since the body-centered atom is not shared with any other unit cell, it contributes fully to only one unit cell.

### Final Answer:
- The atom at the body center of a BCC unit cell is shared by **1 unit cell**.

---