monoclinisk

Monoclinisk, or monoclinic, is one of the seven crystal systems in crystallography. It describes crystals whose unit cell is defined by three vectors a, b, and c with a ≠ b ≠ c and with two right angles, α = γ = 90°, while the third angle, β, is not equal to 90°. In standard conventions, the unique axis is commonly chosen as b, making the angle β between a and c the oblique angle of the cell.

Bravais lattices for the monoclinic system are primitive (P) and base-centered (C). The symmetry of monoclinic crystals is relatively low, with possible point groups 2, m, and 2/m. This corresponds to one twofold rotation axis and, in some cases, a mirror plane or glide plane.

Physical properties of monoclinic crystals reflect anisotropy in both optical and mechanical behavior. Crystals typically form elongated prisms or tabular shapes, and the lattice geometry produces directional variation in properties such as refractive indices and hardness.

Minerals commonly crystallizing in the monoclinic system include gypsum and many mica group minerals, among others. Monoclinic crystals are less symmetric than orthorhombic crystals but more structured than triclinic crystals, occupying an intermediate position in the hierarchy of crystal systems.

In crystallography and materials science, monoclinisk structures are analyzed through unit-cell parameters, symmetry operations, and space groups to determine material properties and crystal behavior.