The atoms in crystals are all located the same distance apart along a specific line. This distance is known as the period, and how much the crystal stays in this consistent shape is its periodicity.

1D

*	*	*	*	*	*

______

period

2D

*	*	*	*	*	*|period

*	*	*	*	*	*|

_______

period

3D

(similar image)

Amorphous materials tend not to have long term periodicity. The degree of crystallinity depends on how much the periodicity continues.

The atoms in crystals are all located the same distance apart a

Stephanie Silberstein

2004-10-24T18:12:00