Iron crystallizes in a body-centered cubic pattern. How many iron atoms are in each unit cell?
A)1
B)2
C)4
D)8
E)9

Question

Quizplus · Accepted Answer

In a body-centered cubic (BCC) structure, 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 the unit cell, for a total of 1 atom from the corners (8 corners * 1/8 = 1). The atom in the center is not shared and contributes fully to the unit cell. Therefore, the total number of atoms per unit cell in a BCC structure is 2 (1 from the corners + 1 from the center).

Iron Crystallizes in a Body-Centered Cubic Pattern