Orthorhombic crystal system
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, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic.
Orthorhombic Bravais lattices
Primitive |
Body-centered |
Base-centered |
Face-centered |
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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, type, and space groups are listed in the table below.
# |
Point group |
Example |
Type |
Space groups |
Name |
Schönflies |
Intl |
Orbifold |
Coxeter |
16-24 |
sphenoidal [2] |
D2 |
222 |
222 |
[2,2]+ |
epsomite |
enantiomorphic |
P222, P2221, P21212, P212121, C2221, C222, F222, I222, I212121 |
25-46 |
pyramidal [2] |
C2v |
mm2 |
*22 |
[2] |
hemimorphite, bertrandite |
polar |
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] |
olivine, aragonite, marcasite |
centrosymmetric |
Pmmm, Pnnn, Pccm, Pban, Pmma, Pnna, Pmna, Pcca, Pbam, Pccn, Pbcm, Pnnm, Pmmn, Pbcn, Pbca, Pnma, Cmcm, Cmce, Cmmm, Cccm, Cmme, Ccce, Fmmm, Fddd, Immm, Ibam, Ibca, Imma |
See also
References
- Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., pp. 69 – 73, ISBN 0-471-80580-7