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Cube 5-Compound


Cube5Compounds

There are a number of attractive polyhedron compounds consisting of five cubes. The first of these (left figures) consists of the arrangement of five cubes in the polyhedron vertices of a dodecahedron (or the centers of the faces of the icosahedron). The first 5-compound compound can be generated by starting with an initial cube centered at the origin and oriented along the axes, then adding four more cubes obtained from the initial cube by rotations through angles -2npi/5 about the axis (1,phi,0) for n=1, 2, 3, 4. The cube 5-compound is the dual of the octahedron 5-compound, and is one of the rhombic triacontahedron stellations (Kabai 2002, p. 185).

A second compound (right figures) can be constructed from the vertices of the first cube 4-compound (E. Weisstein, Sep. 19, 2023).

Cube5CompoundsAndDuals

These cube 5-compounds are illustrated above together with their octahedron 5-compound duals and common midspheres.

The cube 5-compounds are implemented in the Wolfram Language as PolyhedronData[{"CubeFiveCompound", n}] for n=1, 2.

Cube5CompoundsIntersectionsAndConvexHulls

For the first compound, the common solid is a rhombic triacontahedron (Steinhaus 1999, pp. 199 and 209; Ball and Coxeter 1987) and the convex hull is a regular dodecahedron. For the second, the common solid is an unnamed solid illustrated above and the convex hull is a chamfered cube.

Cube5-CompoundStellations

The beautiful figures above show the results of starting with the interior of the compound and including successively larger portions of the space enclosed by its stellations (M. Trott, pers. comm., Feb. 10, 2006). They are therefore rhombic triacontahedron stellations.

The first cube 5-compound can be inscribed on the vertices of an augmented dodecahedron, (first) cube 4-compound, cube-octahedron 5-compound, augmented dodecahedron, deltoidal hexecontahedron, disdyakis triacontahedron, dodecahedron, echidnahedron, great rhombic triacontahedron, great stellated dodecahedron, metabiaugmented dodecahedron, parabiaugmented dodecahedron, pentagonal hexecontahedron, pentakis dodecahedron, rhombic enneacontahedron, rhombic hexecontahedron, rhombic triacontahedron, small triambic icosahedron, spikey, triakis icosahedron, and triaugmented dodecahedron (E. Weisstein, Dec. 25-28, 2009).

The vertices of the first five-cube compound are included among those of the dodecahedron-icosahedron compound, ditrigonal dodecadodecahedron, great ditrigonal icosidodecahedron, and great stellated dodecahedron.

Cube5-CompoundNetCundy

In the above figure, let a=1 be the length of a cube polyhedron edge. Then

x=1/2(3-sqrt(5))
(1)
theta=tan^(-1)((3-sqrt(5))/2) approx 20 degrees54^'
(2)
phi=tan^(-1)((sqrt(5)-1)/2) approx 31 degrees43^'
(3)
psi=90 degrees-phi approx 58 degrees17^'
(4)
alpha=90 degrees-theta approx 69 degrees06^'.
(5)

The compound can be constructed using pieces like those illustrated above (Cundy and Rollett 1989).

Cube5-CompoundNet

Nets are shown above for constructing the first compound such that each cube can be made a different color. For cubes of unit edge lengths, the resulting edge lengths are

s_1=1/4sqrt(130-58sqrt(5))
(6)
s_2=1/2sqrt(27-12sqrt(5))
(7)
s_3=1/4sqrt(50-22sqrt(5))
(8)
s_4=sqrt(5)-2
(9)
s_5=1/4sqrt(42-18sqrt(5))
(10)
s_6=1/2sqrt(5-2sqrt(5))
(11)
s_7=1/2(3-sqrt(5)).
(12)

The surface area of the compound is

 S=165sqrt(5)-360 approx 8.95,
(13)

compared to S=6 for each of the five constituent cubes.

The circumradius for the first compound composed of unit cubes is

 R=1/2sqrt(3),
(14)

and the surface area and volume are

S=165sqrt(5)-360
(15)
V=1/2(55sqrt(5)-120).
(16)

See also

Cube, Ditrigonal Dodecadodecahedron, Dodecahedron, Octahedron 5-Compound, Polyhedron Compound, Rhombic Triacontahedron, Rhombic Triacontahedron Stellations

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References

Ball, W. W. R. and Coxeter, H. S. M. Mathematical Recreations and Essays, 13th ed. New York: Dover, pp. 135 and 137, 1987.Cundy, H. and Rollett, A. "Five Cubes in a Dodecahedron." §3.10.6 in Mathematical Models, 3rd ed. Stradbroke, England: Tarquin Pub., pp. 135-136, 1989.Hart, G. "Standard Compound of Five Cubes." http://www.georgehart.com/virtual-polyhedra/vrml/compound_of_5_cubes_(5_colors).wrl.Hart, G. "Standard Compound of Five Cubes." http://www.georgehart.com/virtual-polyhedra/vrml/cubes_A5_A4.wrl.Kabai, S. Mathematical Graphics I: Lessons in Computer Graphics Using Mathematica. Püspökladány, Hungary: Uniconstant, pp. 161 and 185, 2002.Steinhaus, H. Mathematical Snapshots, 3rd ed. New York: Dover, 1999.Verheyen, H. F. Symmetry Orbits. Boston, MA: Birkhäuser, 2007.

Cite this as:

Weisstein, Eric W. "Cube 5-Compound." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Cube5-Compound.html

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