triklinisk

Triklinisk, in English triclinic, refers to one of the seven crystal systems in crystallography. It describes crystals whose lattice is defined by three unequal axes that are not perpendicular to each other, with all interaxial angles α, β and γ also unequal and not equal to 90 degrees.

In the triclinic system, the symmetry is the lowest of all crystal systems. The unit cell is defined by a ≠ b ≠ c and α ≠ β ≠ γ ≠ 90°, and there are no symmetry elements beyond translations in the most general form. Consequently, only two crystallographic classes occur: 1 (no symmetry) and 1̄ (center of symmetry). Corresponding space groups are P1 and P-1.

Crystals of this system often appear with irregular, sometimes prismatic or tabular shapes, and their external form may not reveal internal symmetry. Because of the low symmetry, triclinic structures can accommodate a wide range of atomic arrangements, which is useful in mineralogy and materials science for describing complex compounds.

Occurrence and examples: many minerals crystallize in the triclinic system. Notable examples include plagioclase feldspars and the mineral kyanite, among others. The triclinic system is less common than some other systems (such as orthorhombic or monoclinic) but plays an important role in representing certain natural and synthetic materials.

Relation to broader crystallography: triclinic is one of the seven crystal systems used to classify crystal lattices by symmetry and geometry. It provides the most general description of lattice parameters, and its study often relies on techniques such as X-ray diffraction to determine atomic positions within the unit cell.