Compound of eight octahedra with rotational freedom
From Wikipedia, the free encyclopedia
| Compound of eight octahedra with rotational freedom | |
|---|---|
 |
|
| Type | Uniform compound |
| Index | UC11 |
| Polyhedra | 8 octahedra |
| Faces | 16+48 triangles |
| Edges | 96 |
| Vertices | 48 |
| Symmetry group | octahedral (Oh) |
| Subgroup restricting to one constituent | 6-fold improper rotation (S6) |
This uniform polyhedron compound is a symmetric arrangement of 8 octahedra, considered as triangular antiprisms. It can be constructed by superimposing eight identical octahedra, and then rotating them in pairs about the four axes that pass through the centres of two opposite octahedral faces. Each octahedron is rotated by an equal (and opposite, within a pair) angle θ.
When θ = 0, all eight octahedra coincide. When θ is 60 degrees, the octahedra coincide in pairs yielding (two superimposed copies of) the compound of four octahedra.
[edit] Cartesian coordinates
Cartesian coordinates for the vertices of this compound are all the permutations of
- (±(1 − cosθ + (√3) sin θ), ±(1 − cosθ − (√3)sinθ), ±(1 + 2 cos θ))
[edit] References
- John Skilling, Uniform Compounds of Uniform Polyhedra, Mathematical Proceedings of the Cambridge Philosophical Society, Vol. 79, pp. 447-457, 1976.
