JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ss043
Anions X form a ccp lattice containing N anions. Cations A occupy some of the voids. Which of the following formula assignments are correct?
AAll tetrahedral voids occupied: AX2X
BHalf of the octahedral voids occupied: AX
COne-third of the tetrahedral voids occupied: AX2XX3
DOne-quarter of the octahedral voids occupied: AX4X
Answer: A, C
There are N octahedral and 2N tetrahedral voids. All tetrahedral voids: A=2N, formula AX2X. Half of octahedral: A=N/2, giving AXX2. One-third of tetrahedral: A=2N/3, giving AX2XX3. One-quarter of octahedral: A=N/4, giving AXX4.