Editing Crystal structure (section)

=== Lattice systems ===
Lattice systems are a grouping of crystal structures according to the point groups of their lattice. All crystals fall into one of seven lattice systems. They are related to, but not the same as the seven [[crystal system]]s. 
{| class="wikitable skin-invert-image"
|+Overview of common lattice systems
!scope="col" rowspan=2| Crystal family
!scope="col" rowspan=2| Lattice system
!scope="col" rowspan=2| Point group <br />([[Schoenflies notation|Schönflies notation]])
!scope="col" colspan=4| 14 Bravais lattices
|-
!scope="col"| Primitive (P)
!scope="col"| Base-centered (S)
!scope="col"| Body-centered (I)
!scope="col"| Face-centered (F)
|- align=center
!scope="row" colspan=2| [[Triclinic]] (a)
| C{{sub|i}}
| [[File:Triclinic.svg|80px|Triclinic]]
aP
|
|
|
|- align=center
!scope="row" colspan=2| [[Monoclinic]] (m)
| C{{sub|2h}}
| [[File:Monoclinic.svg|80px|Monoclinic, simple]]
mP
| [[File:Base-centered monoclinic.svg|80px|Monoclinic, centered]]
mS
|
|
|- align=center
!scope="row" colspan=2| [[Orthorhombic]] (o)
| D{{sub|2h}}
| [[File:Orthorhombic.svg|80px|Orthorhombic, simple]]
oP
| [[File:Orthorhombic-base-centered.svg|80px|Orthorhombic, base-centered]]
oS
| [[File:Orthorhombic-body-centered.svg|80px|Orthorhombic, body-centered]]
oI
| [[File:Orthorhombic-face-centered.svg|80px|Orthorhombic, face-centered]]
oF
|- align=center
!scope="row" colspan=2| [[Tetragonal]] (t)
| D{{sub|4h}}
| [[File:Tetragonal.svg|80px|Tetragonal, simple]]
tP
|
| [[File:Tetragonal-body-centered.svg|80px|Tetragonal, body-centered]]
tI
|
|- align=center
!scope="row" rowspan=2| [[Hexagonal crystal family|Hexagonal]] (h)
! Rhombohedral
| D{{sub|3d}}
| [[File:Rhombohedral.svg|80px|Rhombohedral]]
hR
|
|
|
|- align=center
!scope="row"| Hexagonal
| D{{sub|6h}}
| [[File:Hexagonal latticeFRONT.svg|80px|Hexagonal]]
hP
|
|
|
|- align=center
!scope="row" colspan=2| [[Cubic crystal system|Cubic]] (c)
| O{{sub|h}}
| [[File:Cubic.svg|80px|Cubic, simple]]
cP
|
| [[File:Cubic-body-centered.svg|80px|Cubic, body-centered]]
cI
| [[File:Cubic-face-centered.svg|80px|Cubic, face-centered]]
cF
|}
{{clear}}
The most symmetric, the [[cubic (crystal system)|cubic]] or isometric system, has the symmetry of a [[Cube (geometry)|cube]], that is, it exhibits four threefold rotational axes oriented at 109.5° (the [[tetrahedral angle]]) with respect to each other. These threefold axes lie along the body diagonals of the cube. The other six lattice systems, are [[Hexagonal lattice system|hexagonal]], [[tetragonal]], [[rhombohedral lattice system|rhombohedral]] (often confused with the [[trigonal crystal system]]), [[orthorhombic]], [[monoclinic]] and [[triclinic]].

==== Bravais lattices ====
[[Bravais lattice]]s, also referred to as ''space lattices'', describe the geometric arrangement of the lattice points,<ref name="Physics 1991"/> and therefore the translational symmetry of the crystal. The three dimensions of space afford 14 distinct Bravais lattices describing the translational symmetry. All crystalline materials recognized today, not including [[quasicrystal]]s, fit in one of these arrangements. The fourteen three-dimensional lattices, classified by lattice system, are shown above.

The crystal structure consists of the same group of atoms, the ''basis'', positioned around each and every lattice point. This group of atoms therefore repeats indefinitely in three dimensions according to the arrangement of one of the Bravais lattices. The characteristic rotation and mirror symmetries of the unit cell is described by its [[crystallographic point group]].