Monoclinic System

The monoclinic system is defined by three axes of unequal length. In this geometry, two of the axes intersect at an oblique angle, while the third remains strictly perpendicular to the plane formed by the other two. Because of this specific inclination, the system exhibits relatively low symmetry—typically characterized by a single twofold rotation axis or a single mirror plane—and includes two Bravais lattices: simple monoclinic and base-centered monoclinic.

Lattice parameters: $a \neq b \neq c$, and angles $\alpha = \gamma = 90^\circ, \beta \neq 90^\circ$.

Examples: Gypsum, Orthoclase, Borax, and Sodium Sulfate.