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However, the rhombohedral axes are often shown (for the rhombohedral lattice) in textbooks because this cell reveals the 3 m symmetry of the crystal lattice. The rhombohedral unit cell for the hexagonal Bravais lattice is the D-centered [ 1 ] cell, consisting of two additional lattice points which occupy one body diagonal of the unit cell with ...
It can be used to define the rhombohedral lattice system, a honeycomb with rhombohedral cells. A rhombohedron has two opposite apices at which all face angles are equal; a prolate rhombohedron has this common angle acute, and an oblate rhombohedron has an obtuse angle at these vertices.
In monoclinic, trigonal, tetragonal, and hexagonal systems there is one unique axis (sometimes called the principal axis) which has higher rotational symmetry than the other two axes. The basal plane is the plane perpendicular to the principal axis in these crystal systems.
This category lists every crystal element that exists in a rhombohedral structure at STP. Pages in category "Chemical elements with rhombohedral structure" The following 6 pages are in this category, out of 6 total.
carbon-nonmetal (e.g. CO 2, CS 2) [n 17] or organic (e.g. CH 4, C 6 H 12 O 6) compounds With hydrogen ( hydrides ) ionic, with alkali metals , alkaline earth metals
Tricalcium phosphate has three recognised polymorphs, the rhombohedral β form (shown above), and two high temperature forms, monoclinic α and hexagonal α′. β-Tricalcium phosphate has a crystallographic density of 3.066 g cm −3 while the high temperature forms are less dense, α-tricalcium phosphate has a density of 2.866 g cm −3 and ...
Phase transitions (phase changes) that help describe polymorphism include polymorphic transitions as well as melting and vaporization transitions. According to IUPAC, a polymorphic transition is "A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point) to another phase of the same chemical composition with a different crystal structure."
Germanium telluride exists in three major crystalline forms, room-temperature α (rhombohedral) and γ (orthorhombic) structures and high-temperature β (cubic, rocksalt-type) phase; α phase being most phase for pure GeTe below the ferroelectric Curie temperature of approximately 670 K (746 °F; 397 °C).