View source for Crystal symmetry

{| align="center" style="border: 1px solid #999; background-color:#FFFFFF"
|-
! colspan="4" bgcolor="#EFEFEF" | '''Crystal Systems'''
|-align="center" style="background-color:#1188ee; color:#ffffff;"
!System
!Minimum symmetry
!Dimensional requirements for unit cell
|--bgcolor="#eeeeee"
| [[wikipedia:Triclinic|Triclinic]]
|| none
|| none
|-----
| [[wikipedia:Monoclinic|Monoclinic]]
|| Twofold axis (parallel to '''b''')
|| '''a''' and '''c''' are both perpendicular to '''b''' (but not to each other)
|--bgcolor="#eeeeee"
| [[wikipedia:Orthorhombic|Orthorhombic]]
|| Three mutually perpendicular twofold axes
|| '''a''', '''b''', and '''c''' all perpendicular
|-----
| [[wikipedia:Tetragonal|Tetragonal]]
|| Fourfold axis (parallel to '''c''')
|| '''a''', '''b''', and '''c''' all perpendicular; '''a''' and '''b''' equal in length
|--bgcolor="#eeeeee"
| [[wikipedia:Rhombohedral|Rhombohedral]] (or Trigonal)
|| Threefold axis (parallel to '''c''')
|| '''a''', '''b''' perpendicular to '''c''' and at 120° to each other; '''a''' and '''b''' equal
|-----
| [[wikipedia:Hexagonal_%28crystal_system%29|Hexagonal]]
|| Sixfold axis (parallel to '''c''')
|| Same as trigonal
|--bgcolor="#eeeeee"
| [[wikipedia:Cubic_crystal_system|Cubic]]
|| Threefold axes along cube diagonals
|| '''a''', '''b''', and '''c''' perpendicular and equal in length
|}

== Bravais lattices ==
 see: [[wikipedia:Bravais lattice|Bravais lattice]]

== Space groups ==
 see: [[wikipedia:Space groups|Space groups]], [http://fr.wikipedia.org/wiki/Syst%C3%A8me_cristallin#Les_230_groupes_d.27espace Overview of all space groups] (in French)

[[Category:Crystallography]]