In crystallography, the orthorhombic crystal system is one of the 7 lattice point groups. Orthorhombic lattices result from stretching a cubic lattice along two of its lattice vectors by two different factors, resulting in a rectangular prism with a rectangular base (a by b, which is different from a) and height (c, which is different from a and b). All three bases intersect at 90° angles. The three lattice vectors remain mutually orthogonal.

There are four orthorhombic Bravais lattices: simple orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic.

The point groups (or crystal classes) that fall under this crystal system are listed below, followed by their representations in international notation and Schoenflies notation, and mineral examples.

Crystallography

Orthorhombisches Kristallsystem | Rombiline süngoonia | 사방정계 | Ortorrômbico | Ромбическая сингония | 斜方晶系