Rhombohedron
In Géométrie, a rhombohedron a polyhedron with three dimensions resembling the Cube, except its faces are not square but in form of Losange S. It is a particular case of a Parallélépipède where all the edges are same length. The rhombohedron is besides the result of the deformation of the cube in the direction of a large diagonal.
In general, the rhombohedron can have three types of rhombic faces by adequate opposite faces.
If all the interior angles not-blunt of the faces are equal, it can be called a trigonal Trapèzoèdre.
These properties are important in Cristallographie, and in particular make it possible to explain the relationship between the crystalline systems trigonal, hexagonal and cubic.
Another particular case is the following: there exists a symmetry plane through four tops (with the Groupe of symmetry '' C '' '' 2h '' ), and a special case where there exists another symmetry plane through four other tops (with the group of symmetry '' D '' '' 2h '' ).
The Cube combines these particular properties, and thus is a particular case of rhombohedron.
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