Question

If three elements X, Y & Z crystallized in cubic solid lattice with X atoms at corners, Y atoms at cube centre& Z -atoms at the edges, then the formula of the compound is:

• A. XYZ
• B. XY3Z
• C. XYZ3
• D. X3YZ

Answer 1

Answer: (C)

XYZ3

Answer 2

Atom X is shared by 8 corners

1 atoms of Z is shared by 4 unit cells

Atom Y is present at centre of the unit cell

Hence, effective number of atoms of X per unit cell = $8 \times \frac{1}{8} = 1$

Effective number of atoms of Z per unit cell = $\frac{12}{4} = 3$

Effective number of atoms of Y per unit cell = 1

Hence, the formula of the compound is XYZ3