Orthorombisk

Orthorhombic is a crystal system used in mineralogy and crystallography to describe the geometry of a crystal lattice. It is defined by three mutually perpendicular axes, a, b, and c, which meet at right angles (α = β = γ = 90°) but have unequal lengths (a ≠ b ≠ c). This distinction sets it apart from cubic (a = b = c) and tetragonal (a = b ≠ c) systems.

There are four Bravais lattices in the orthorhombic system: primitive (P), base-centered (C), body-centered (I), and face-centered (F). Each lattice type accommodates the orthorhombic symmetry while preserving the condition of right angles between the axes. The combination of lattice type and symmetry operations gives rise to the characteristic orthorhombic crystal forms, often appearing as rectangular prisms or tabular crystals with distinct faces.

In practice, orthorhombic crystals exhibit a range of optical and physical properties dependent on composition and defect structure. The system supports many minerals and compounds, including olivine group minerals (such as forsterite and fayalite), enstatite, aragonite, and barite, which crystallize with orthorhombic unit cells. In X-ray and electron diffraction, patterns reflect the three unequal axis lengths and 90° angles, enabling discrimination from other crystal systems.

Overall, the orthorhombic system is a foundational category in crystallography, capturing a broad class of minerals and materials whose structural regularity is defined by three perpendicular, differently-sized axes.