# 6.3.1: Unit Cells (Problems)

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PROBLEM $$\PageIndex{1}$$

Describe the crystal structure of iron, which crystallizes with two equivalent metal atoms in a cubic unit cell.

The structure of this low-temperature form of iron (below 910 °C) is body-centered cubic. There is one-eighth atom at each of the eight corners of the cube and one atom in the center of the cube.

PROBLEM $$\PageIndex{2}$$

Describe the crystal structure of Pt, which crystallizes with four equivalent metal atoms in a cubic unit cell.

This structure of platinum is a face-centered cubic. There is one-eighth atom at each of the eight corners of the cube and one-half atom on each of the six faces of the cube.

PROBLEM $$\PageIndex{3}$$

What is the coordination number of a chromium atom in the body-centered cubic structure of chromium?

eight

PROBLEM $$\PageIndex{4}$$

What is the coordination number of an aluminum atom in the face-centered cubic structure of aluminum?