Q. In the face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is
A) $A_{2}B$
B) $AB_{2}$
C) $A_{2}B_{2}$
D) $A_{2}B_{5}$
Explanation
(d)
Number of atoms $(A)$ per unit cell $= 8 \times \frac{1}{8} = 1$
Number of atoms $(B)$ per unit cell $= (6 - 1) \times \frac{1}{2} = \frac{5}{2}$
(One atom B is missing)
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Thus, formula is $A_{1}B_{5/2} = A_{2}B_{5}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.