Cubic crystal system
Crystallographic system where the unit cell is in the shape of a cube / From Wikipedia, the free encyclopedia
In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3b/Kubisches_Kristallsystem.jpg/640px-Kubisches_Kristallsystem.jpg)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/8/86/FCC_primative-cubic_cells.svg/320px-FCC_primative-cubic_cells.svg.png)
There are three main varieties of these crystals:
- Primitive cubic (abbreviated cP and alternatively called simple cubic)
- Body-centered cubic (abbreviated cI or bcc)
- Face-centered cubic (abbreviated cF or fcc)
Note: the term fcc is often used in synonym for the cubic close-packed or ccp structure occurring in metals. However, fcc stands for a face-centered-cubic Bravais lattice, which is not necessarily close-packed when a motif is set onto the lattice points. E.g. the diamond and the zincblende lattices are fcc but not close-packed. Each is subdivided into other variants listed below. Although the unit cells in these crystals are conventionally taken to be cubes, the primitive unit cells often are not.