# Orthorhombic crystal system

(Redirected from Orthorhombic)

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

## Bravais lattices

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

Orthorhombic Bravais lattices
Name Primitive
(P)
Body-centered
(I)
Base-centered
(A, B or C)
Face-centered
(F)
Pearson symbol oP oI oS oF
Unit cell

## Crystal classes

The orthorhombic crystal system class names, examples, Schönflies notation, Hermann-Mauguin notation, point groups, International Tables for Crystallography space group number,1 orbifold notation, type, and space groups are listed in the table below.

# Point group Type
(Example)
Space groups
Name Schön. Intl Orb. Cox.
16-24 sphenoidal 2 D2 222 222 [2,2]+ enantiomorphic
(epsomite)
P222, P2221, P21212, P212121
C2221, C222
F222
I222, I212121
25-46 pyramidal 2 C2v mm2 *22 [2] polar
(hemimorphite, bertrandite)
Pmm2, Pmc21, Pcc2, Pma2, Pca21, Pnc2, Pmn21, Pba2, Pna21, Pnn2
Cmm2, Cmc21, Ccc2
Amm2, Aem2, Ama2, Aea2
Fmm2, Fdd2
Imm2, Iba2, Ima2
47-74 bipyramidal 2 D2h mmm *222 [2,2] centrosymmetric
(olivine, aragonite, marcasite)
Pmmm, Pnnn, Pccm, Pban, Pmma, Pnna, Pmna, Pcca, Pbam, Pccn, Pbcm, Pnnm, Pmmn, Pbcn, Pbca, Pnma
Cmcm, Cmca, Cmmm, Cccm, Cmme, Ccce
Fmmm, Fddd
Immm, Ibam, Ibca, Imma