Compound of three tetrahedra

In geometry, a compound of three tetrahedra can be constructed by three tetrahedra rotated by 60 degree turns along an axis of the middle of an edge. It has dihedral symmetry, D3d, order 12. It is a uniform prismatic compound of antiprisms, UC23.

Compound of 3 digonal antiprisms
TypeUniform
compound
Uniform indexUC23 (n=3, p=2, q=1)
Polyhedra3 digonal antiprisms
(tetrahedra)
Faces12 triangles
Edges24
Vertices12
Symmetry groupD6d, order 12
Subgroup restricting
to one constituent
D2d, order 4

It is similar to the compound of two tetrahedra with 90 degree turns. It has the same vertex arrangement as the convex hexagonal antiprism.

A subset of edges of this compound polyhedron can generate a compound regular skew polygon, with 3 skew squares. Each tetrahedron contains one skew square. This regular compound polygon containing the same symmetry as the uniform polyhedral compound.

References

  • Skilling, John (1976), "Uniform Compounds of Uniform Polyhedra", Mathematical Proceedings of the Cambridge Philosophical Society, 79: 447–457, doi:10.1017/S0305004100052440, MR 0397554.
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