The type of void present at the centre of the ccp unit cell is

Options

A. Trigonal void
B. Tetrahedral void
C. Octahedral void
D. All of these

Answer

To determine the type of void present at the center of the cubic close-packed (ccp) unit cell, we need to analyze the structure of the ccp unit cell, which is also known as face-centered cubic (fcc).

### Step-by-Step Solution:

1. **Understanding the ccp Structure**:
- The ccp structure consists of atoms located at each of the corners of the cube and at the centers of each face of the cube.

2. **Identifying the Types of Voids**:
- In a ccp unit cell, there are two main types of voids: octahedral voids and tetrahedral voids.
- Octahedral voids are formed when six atoms surround a central void, while tetrahedral voids are formed when four atoms surround a central void.

3. **Location of Voids**:
- In the ccp unit cell, octahedral voids are located at the center of the cube (body center) and at the midpoints of the edges of the cube.
- Tetrahedral voids are located within the cube, specifically in the spaces formed by the arrangement of the atoms.

4. **Void at the Center of the ccp Unit Cell**:
- The void located at the center of the ccp unit cell is an **octahedral void**. This is because it is surrounded by six atoms (the atoms at the face centers and the corners of the cube).

5. **Conclusion**:
- Therefore, the type of void present at the center of the ccp unit cell is an **octahedral void**.