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Tetrahedral-Octahedral Honeycomb


The tetrahedral-octahedral honeycomb, also called the alternated cubic honeycomb, is the quasiregular honeycomb of three-dimensional Euclidean space whose cells are regular tetrahedra and regular octahedra (Coxeter 1940, 1973).

Eight tetrahedra and six octahedra meet at every vertex, so the vertex figure is a cuboctahedron. Double-counting vertex-cell incidences in a periodic repeat unit shows that the numbers of tetrahedral and octahedral cells occur in the ratio 2:1. At every polyhedron edge, two tetrahedra and two octahedra meet. This is possible because their dihedral angles are cos^(-1)(1/3) and cos^(-1)(-1/3), whose sum is pi.

Its vertex set is the face-centered cubic lattice, and the corresponding Voronoi cells are rhombic dodecahedra. One regular octahedron together with the eight regular tetrahedra attached to its faces forms a stella octangula. Finite slabs of its 1-skeleton are used as octet trusses.


See also

Alternated Cubic Honeycomb, Cubic Close Packing, Cuboctahedron, Honeycomb, Octahedron, Octet Truss, Regular Tetrahedron, Rhombic Dodecahedron, Stella Octangula

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References

Coxeter, H. S. M. "Regular and Semi-Regular Polytopes I." Math. Z. 46, 380-407, 1940. https://doi.org/10.1007/BF01181449.Coxeter, H. S. M. "Other Honeycombs." §4.7 in Regular Polytopes, 3rd ed. New York: Dover, pp. 69-72, 1973.

Cite this as:

Weisstein, Eric W. "Tetrahedral-Octahedral Honeycomb." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Tetrahedral-OctahedralHoneycomb.html

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