An example of the tetragonal crystals, wulfenite

In crystallography, the tetragonal crystal system is one of the 7 lattice point groups. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base (a by a) and height (c, which is different from a).

There are two tetragonal Bravais lattices: the simple tetragonal (from stretching the simple-cubic lattice) and the centered tetragonal (from stretching either the face-centered or the body-centered cubic lattice).

Simple tetragonal

Body-centered tetragonal

The point groups that fall under this crystal system are listed below, followed by their representations in international notation and Schoenflies notation, and mineral examples.^[1][2]

Name	International	Schoenflies	Example
Ditetragonal dipyramidal		D4h	rutile, pyrolusite, zircon
Ditetragonal pyramidal	4mm	C4v	diaboleite
Tetragonal dipyramidal		C4h	scheelite, wulfenite, leucite
Tetragonal pyramidal	4	C4	pinnoite, richellite
Tetragonal scalenohedral		D2d	chalcopyrite, stannite
Tetragonal trapezohedral	422	D4	cristobalite, wardite
Tetragonal disphenoidal		S4	cahnite, tugtupite

[edit] See also

• Crystal structure
• point groups
• Bravais lattices

[edit] References