TETRAGONAL CRYSTAL SYSTEM

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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).

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.
{| class="wikitable"
!Name!!International!!Schoenflies!!Example
|-
|ditetragonal bipyramidal
|
|''D_4h''
|rutile
|-
|ditetragonal pyramidal
|$4mm$
| ''C_4v''
|diaboleite
|-
|tetragonal bipyramidal
|
|''C_4h''
|scheelite
|-
|tetragonal pyramidal
|4
|''C₄''
|wulfenite
|-
|ditetragonal alternating
|$overline\{4\}2m$
|''D_2d''
|chalcopyrite
|-
|tetragonal trapezohedral
|422
|''D₄''
|phosgenite
|-
|tetragonal alternating
|$overline\{4\}$
|''S₄''
|cahnite
|}

Contents

References

References

★ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed., pp. 73 - 78, ISBN 0-471-80580-7