A compound formed by elements `X` and `Y` has a cubic structure in which `X` atoms are at the corner of the cube and `Y` atoms are at the face centres. One atoms `X` is misssing from the corner.
a. Calculate (i). `Z_(eff')` (ii). total number of the atoms in the cube, and (iii). formula of the compound.
b. If alll the atoms are removed from one of the faces of the cube containing atoms at corners, as in (a) above, calculate (i) `Z_(eff')` (ii) total number of atoms in a cube, and (iii) formula of the compound.

Explanation

To solve the problem step by step, we will break down the calculations for both cases (a and b) as described in the question.

### Part (a)

**Given:**
- `X` atoms are at the corners of the cube.
- `Y` atoms are at the face centers.
- One `X` atom is missing from the corner.
...