The Silicon Molecule. Large numbers of silicon atoms, through their valence electrons, can bond together to form a crystal. In a crystalline solid, each silicon atom normally shares one of its four valence electrons in a "covalent" bond with each of four neighboring silicon atoms. The solid, then, consists of basic units of five silicon atoms: the original atom plus the four other atoms with which it shares its valence electrons.

In the basic unit of a crystalline silicon solid, a silicon atom shares each of its four valence electrons with each of four neighboring atoms.

The solid silicon crystal, then, is composed of a regular series of units of five silicon atoms. This regular, fixed arrangement of silicon atoms is known as the "crystal lattice."

More:

• An Atomic Description of Silicon
• The Silicon Molecule
• Introducing Phosphorous
• Introducing Boron
• Other Semiconductor Materials
• Absorption and Conduction