Monoclinikus

Monoclinikus, in crystallography often translated as monoclinic in English, refers to one of the seven crystal systems. A monoclinic crystal lattice is defined by three axes a, b, and c with two angles at 90 degrees (alpha = gamma = 90°) and the third angle beta typically different from 90°. As a result, the unit cell is oblique along one axis, usually taken as the b-axis, which is considered the unique axis.

The monoclinic system has lower symmetry than the orthorhombic system. Its possible symmetry elements include either a single twofold rotation axis along the b direction or a mirror plane perpendicular to b, or both in higher-symmetry variants. Consequently, there are multiple monoclinic space groups that describe the arrangement of atoms within the lattice.

Crystals of monoclinic systems commonly form prismatic, elongate, or tabular habits, reflecting the constraints imposed by the lattice angles. The appearance of faces and the refractive properties are influenced by the beta angle and the overall lattice parameters.

Minerals that crystallize in the monoclinic system include gypsum (CaSO4·2H2O), augite (a clinopyroxene), and several sheet silicates such as some micas. In practice, monoclinic crystals exhibit a range of optical and physical properties, often showing distinct cleavage and symmetry consistent with their lower-dimensional rotational or mirror symmetries.

In summary, monoclinikus describes a crystal system characterized by alpha and gamma equal to 90 degrees, beta different from 90 degrees, and a lattice symmetry that is intermediate between orthorhombic and triclinic.