Potassium crystallizes in a body-centered cubic lattice. How many atoms are there per unit cell
A) 1
B) 2
C) 4
D) 6
E) 8

Question

Quizplus · Accepted Answer

In a body-centered cubic (bcc) lattice, there is one atom at each corner of the cube and one atom in the center of the cube. Each corner atom is shared among eight unit cells, contributing 1/8 of an atom per corner to a single unit cell. Since there are eight corners, this adds up to one whole atom from the corners. The atom in the center of the cube belongs entirely to the unit cell. Therefore, the total number of atoms per unit cell in a bcc lattice is 1 (from the corners) + 1 (from the center) = 2.

Potassium Crystallizes in a Body-Centered Cubic Lattice