Arrange the three common cubic unit cells in order from least dense to most dense packing.
A) Face-centered cubic

Question

Arrange the three common cubic unit cells in order from least dense to most dense packing.
A) Face-centered cubic < body-centered cubic < primitive cubic
B) Primitive cubic < body-centered cubic < face-centered cubic
C) Primitive cubic < face-centered cubic < body-centered cubic
D) Body-centered cubic < primitive cubic < face-centered cubic
E) Body-centered cubic < face-centered cubic < primitive cubic

Quizplus · Accepted Answer

The primitive cubic has the least dense packing because it has the smallest number of atoms per unit cell, only one. The body-centered cubic has a higher density than the primitive cubic because it has two atoms per unit cell, but the atoms are not as closely packed as in the face-centered cubic. The face-centered cubic has the most dense packing because it has four atoms per unit cell and they are situated at the corners and the center of each face of a cube, resulting in a tightly packed structure. Therefore, the order from least to most dense packing is primitive cubic < body-centered cubic < face-centered cubic.

Arrange the Three Common Cubic Unit Cells in Order from Least