Materials. V2.01 17-Jun-2004 1.
Essential Documents. Assignment 1. Assignment 2. Assignment 3. Assignment 4. Assignment: Materials Testing. Further reading/ useful sites. Sara McCaslin. Heat treatment of steel. Phase Diagrams Part 1. Phase Diagrams Part 2. 12.2: The Arrangement of Atoms in Crystalline Solids. Because a crystalline solid consists of repeating patterns of its components in three dimensions (a crystal lattice), we can represent the entire crystal by drawing the structure of the smallest identical units that, when stacked together, form the crystal.
This basic repeating unit is called a unit cell. For example, the unit cell of a sheet of identical postage stamps is a single stamp, and the unit cell of a stack of bricks is a single brick. In this section, we describe the arrangements of atoms in various unit cells. Unit cells are easiest to visualize in two dimensions. In many cases, more than one unit cell can be used to represent a given structure, as shown for the Escher drawing in the chapter opener and for a two-dimensional crystal lattice in Figure 12.2.