Part II: Unit Cells of Metals discusses how to use a unit cell to describe a two-dimensional structure, then extends the concept to metals using the four basic unit cells of the metals: the simple cubic, body-centered cubic, face-centered cubic, and hexagonal cells. The relationships between radii of the metal atoms in the cubic structures and the cell dimensions are developed. Students are also introduced to counting the number of atoms in a unit cell. Pseudo-animation is particularly effective in illustrating the fractions of atoms that lie in the various unit cells.

Illustration showing the number of atoms occupying a body-centered cubic unit cell from A Window on the Solid State.

Two versions of each part are provided. One is a student tutorial that allows a student to work through the material at her/his own pace. This version requires students to identify or predict structural features and includes pop-up boxes that confirm or correct choices. Hot words are used to link ideas and provide definitions. The other version is designed to be used in lecture demonstration; it contains all graphics and summary statements from the tutorial program, but is less interactive.

Comparison of layers in hexagonal close-packed and cubic close-packed structures from A Window on the Solid State.

Both the lecture and tutorial versions are intended as supplements to an introductory presentation, either at the general chemistry level or at the first introduction of the structures of metals at the undergraduate level. These programs emphasize the qualitative and geometric aspects of the structures presented. Although no numerical calculations are requested in these programs, students will be well prepared to tackle quantitative exercises by the information presented.