Triclinic crystal system

A crystal system with three unequal axes all intersecting at oblique angles

Overview

The triclinic crystal system is one of the seven crystal systems in crystallography. It is characterized by having three axes of unequal length, all of which intersect at oblique angles. This means that none of the axes are perpendicular to each other, and the angles between them are not 90 degrees.

Characteristics

In the triclinic system, the unit cell is defined by three vectors of unequal length, denoted as a, b, and c. The angles between these vectors, denoted as _, _, and _, are all different and none of them are 90 degrees. This results in the least symmetrical of all the crystal systems.

Symmetry

The triclinic system has the lowest symmetry of all the crystal systems. It has only one point group: the identity group, which is denoted as 1, and the inversion group, denoted as \(\bar{1}\). This means that triclinic crystals have no rotational symmetry axes.

Examples

A common example of a mineral that crystallizes in the triclinic system is microcline, a type of feldspar. Microcline is often found in granite and is known for its distinctive grid-like twinning pattern.

Microcline, a mineral that crystallizes in the triclinic system

Related pages

• Crystal system
• Crystallography
• Mineral
• Symmetry in crystallography

References

• Klein, Cornelis and Cornelius S. Hurlbut, Jr. (1985). Manual of Mineralogy (20th ed.). John Wiley & Sons.
• "Triclinic crystal system." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited October 2023.