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Octahedron


Octahedra

A (general) octahedron is a polyhedron having eight faces. Examples include the 4-trapezohedron, augmented triangular prism (Johnson solid J_(49)), bislit cube, Dürer solid, elongated gyrobifastigium, gyrobifastigium (Johnson solid J_(26)), heptagonal pyramid, hexagonal prism, regular octahedron, square dipyramid, triangular cupola (Johnson solid J_3), tridiminished icosahedron (Johnson solid J_(63)), tritetrahedron, and truncated tetrahedron.

There are 257 convex octahedra, corresponding to the duals of the octahedral graphs. The convex octahedra consisting of regular polygonal faces of equal edge lengths are summarized in the following table. They all have V-E=6, as required by the polyhedral formula.

polyhedrondegree sequenceVE
truncated tetrahedron3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 31218
heptagonal pyramid3, 3, 3, 3, 3, 3, 3, 7814
triangular cupola3, 3, 3, 3, 3, 3, 4, 4, 4915
tridiminished icosahedron3, 3, 3, 3, 3, 3, 4, 4, 4915
gyrobifastigium3, 3, 3, 3, 4, 4, 4, 4814
augmented triangular prism3, 3, 4, 4, 4, 4, 4713
octahedron4, 4, 4, 4, 4, 4612

The regular octahedron, often simply called "the" octahedron, is the Platonic solid P_4 with six polyhedron vertices, 12 polyhedron edges, and eight equivalent equilateral triangular faces, denoted 8{3}. It is also uniform polyhedron U_5 and Wenninger model W_2. It is given by the Schläfli symbol {3,4} and Wythoff symbol 4|23. The octahedron of unit side length is the antiprism of n=3 sides with height h=sqrt(6)/3. The octahedron is also a square dipyramid with equal edge lengths.


See also

Dürer's Solid, Escher's Solid, Icosahedron, Jumping Octahedron, Octahedral Graph, Octahedral Group, Regular Octahedron, Stella Octangula, Tritetrahedron, Truncated Octahedron Explore this topic in the MathWorld classroom

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Cite this as:

Weisstein, Eric W. "Octahedron." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Octahedron.html

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