
The compounds of ten octahedra UC
15 and UC
16 are two
uniform polyhedron compounds. They are composed of a symmetric arrangement of 10
octahedra, considered as triangular
antiprisms, aligned with the axes of three-fold rotational symmetry of an
icosahedron
In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes and . The plural can be either "icosahedra" () or "icosahedrons".
There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrica ...
. The two compounds differ in the orientation of their octahedra: each compound may be transformed into the other by rotating each octahedron by 60 degrees.
Cartesian coordinates
Cartesian coordinates
A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in t ...
for the vertices of this compound are all the cyclic permutations of
: (0, ±(τ
−1 + 2''s''τ), ±(τ − 2sτ
−1))
: (±( − ''s''τ
2), ±( + ''s''(2τ − 1)), ±( + ''s''τ
−2))
: (±(τ
−1 − ''s''τ), ±(τ + ''s''τ
−1), ±3''s'')
where τ = (1 + )/2 is the
golden ratio (sometimes written φ) and ''s'' is either +1 or −1. Setting ''s'' = −1 gives UC
15, while ''s'' = +1 gives UC
16.
See also
*
Compound of three octahedra
*
Compound of four octahedra
*
Compound of five octahedra
*
Compound of twenty octahedra
References
*.
Polyhedral compounds
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