AskDefine | Define rhombohedral

Dictionary Definition

rhombohedral adj : having three-fold symmetry [syn: trigonal]

User Contributed Dictionary

English

Adjective

rhombohedral
  1. Having three equal axes and oblique angles.

Extensive Definition

In crystallography, the rhombohedral (or trigonal) crystal system is one of the seven lattice point groups, named after the two-dimensional rhombus. A crystal system is described by three basis vectors. In the rhombohedral system, the crystal is described by vectors of equal length, of which all three are not mutually orthogonal. The rhombohedral system can be thought of as the cubic system stretched diagonal along a body. a = b = c; \alpha = \beta = \gamma \neq 90^\circ. In some classification schemes, the rhombohedral system is grouped into a larger hexagonal system.
There exists only one rhombohedral Bravais lattice.

List of particulars

The point groups which fall under this crystal system are listed below, followed by their representations in international notation (Hermann-Mauguin notation) and Schoenflies notation, and example crystals.

References

  • Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., pp. 78 - 89, ISBN 0-471-80580-7
rhombohedral in German: Trigonales Kristallsystem
rhombohedral in Basque: Kristal-sistema erronboedriko
rhombohedral in Korean: 삼방정계
rhombohedral in Latvian: Trigonālā singonija
rhombohedral in Norwegian: Trigonal
rhombohedral in Polish: Układ trygonalny
rhombohedral in Russian: Тригональная сингония
rhombohedral in Slovak: Trigonálna sústava
rhombohedral in Serbian: Ромбоедарска кристална система
rhombohedral in Serbo-Croatian: Romboedarska kristalna sistema
rhombohedral in Swedish: Trigonala kristallsystemet
rhombohedral in Ukrainian: Тригональна сингонія
rhombohedral in Chinese: 三方晶系
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