Q. Structure of a mixed oxide is cubic close-packed (c.c.p.). The cubic unit cell of mixed oxide is composed of oxide ions. One fourth of the tetrahedral voids are occupied by divalent metal A and the octahedral voids are occupied by a monovalent metal B. The formula of the oxide is
A) ABO₂
B) A₂BO₂
C) A₂B₃O₄
D) AB₂O₂
Explanation
[Solution from source] A ccp unit cell has 4 oxide ions, 8 tetrahedral voids and 4 octahedral voids. A occupies 1/4 of the tetrahedral voids (2 per cell) and B all octahedral voids (4 per cell), giving A₂B₄O₄ = AB₂O₂; the charges balance (2 × 2 + 4 × 1 = 8 = 4 × 2). Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.