Monoclinicmuodossa

Monoclinicmuodossa, or monoclinic form, refers to crystals or materials that crystallize in the monoclinic crystal system. In this system, the unit cell is defined by three unequal axes a, b, c with two angles of 90 degrees (α = γ = 90°) and one oblique angle (β ≠ 90°). Consequently, the ab plane is rectangular while the angle between a and c is β. The lattice can be primitive (P) or base-centered (C), with symmetry typically supporting a single unique axis, usually b.

The monoclinic system exhibits limited symmetry compared to higher-symmetry systems. Common point groups include 2, m, and 2/m. Many monoclinic crystals have a unique axis along b, and their symmetry may arise from a twofold rotation axis or a mirror plane parallel to that axis. Space groups in this system reflect these constraints, and the overall crystal habit often appears as prisms or tabular forms elongated along the unique axis.

Occurrences and properties: Monoclinic minerals are widespread and include gypsum and clinopyroxenes, as well as several micas such as muscovite and biotite. Monoclinic crystals typically display anisotropic physical properties and biaxial optical behavior, with refractive indices that differ along the three principal directions. In crystallography and materials science, determining the lattice parameters a, b, c and the angle β is essential for indexing diffraction data and understanding phase relationships and polymorphism in monoclinic materials.