A crystal is made of particles A and B. A forms FCC packing and B occupies all the octahedral voids. If all the particles along the plane as shown in figure are removed, then the formula of the crystal would be :

Options

A. AB
B. `A_(5)B_(7)`
C. `A_(7)B_(5)`
D. None of these

Explanation

To solve the problem, we need to determine the formula of the crystal after removing all the particles along a specified plane. The crystal is made up of particles A and B, where A forms a face-centered cubic (FCC) packing and B occupies all the octahedral voids.

### Step-by-Step Solution:

1. **Understanding FCC Packing**:
- In a face-centered cubic (FCC) structure, there are particles at the corners and at the face centers of the cube.
- There are 8 corner atoms, each contributing \( \frac{1}{8} \) of an atom (total contribution from corners = \( 8 \times \frac{1}{8} = 1 \)).
- There are 6 face-centered atoms, each contributing \( \frac{1}{2} \) of an atom (total contribution from face centers = \( 6 \times \frac{1}{2} = 3 \)).
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