If a salt has a face-centered cubic (fcc) unit cell and a 1:2 cation:anion stoichiometry with cations occupying the fcc positions, then the anions fill all the ________ holes.
A)Cubic
B)octahedral
C)tetrahedral
D)octahedral and tetrahedral
E)cubic, octahedral, and tetrahedral

Question

Quizplus · Accepted Answer

In a face-centered cubic structure, there are tetrahedral holes between the close-packed layers. Since the anion-cation ratio is 2:1, all the tetrahedral holes will be filled by anions. Therefore, the correct answer is (C) tetrahedral.

If a Salt Has a Face-Centered Cubic (Fcc) Unit Cell