(Redirected from Triclinic)
In
crystallography, the 'triclinic'
crystal system is one of the 7 lattice
point groups. A crystal system is described by three basis
vectors. In the triclinic system, the
crystal is described by vectors of unequal length, as in the
orthorhombic system. In addition, all three vectors are not mutually
orthogonal.
The triclinic lattice is the least symmetric of the 14 three-dimensional
Bravais lattices. It has (itself) the minimum symmetry all lattices have: points of inversion at each lattice point and at 7 more points for each lattice point: at the midpoints of the edges and the faces, and at the center points. It is the only lattice type that itself has no mirror planes.
The
point groups that fall under this crystal system are listed below, followed by their representations in international notation and
Schoenflies notation.
{| class="wiktable"
!Name!!International!!Schoenflies
|-
|triclinic normal
|
| ''C
i'' (also denoted by ''S
2'')
|-
|triclinic hemihedral
|1
| ''C
1''
|}
With each only one space group is associated.
Mineral examples include
plagioclase,
microcline,
rhodonite,
turquoise,
wollastonite and
amblygonite, all in triclinic normal (bar 1).
References
★ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed., pp. 64 - 65, ISBN 0-471-80580-7