Snub polyhedron

Last updated
Polyhedron
ClassNumber and properties
Platonic solids
(5, convex, regular)
Archimedean solids
(13, convex, uniform)
Kepler–Poinsot polyhedra
(4, regular, non-convex)
Uniform polyhedra
(75, uniform)
Prismatoid:
prisms, antiprisms etc.
(4 infinite uniform classes)
Polyhedra tilings (11 regular, in the plane)
Quasi-regular polyhedra
(8)
Johnson solids (92, convex, non-uniform)
Pyramids and Bipyramids (infinite)
Stellations Stellations
Polyhedral compounds (5 regular)
Deltahedra (Deltahedra,
equilateral triangle faces)
Snub polyhedra
(12 uniform, not mirror image)
Zonohedron (Zonohedra,
faces have 180°symmetry)
Dual polyhedron
Self-dual polyhedron (infinite)
Catalan solid (13, Archimedean dual)

In geometry, a snub polyhedron is a polyhedron obtained by performing a snub operation: alternating a corresponding omnitruncated or truncated polyhedron, depending on the definition. Some, but not all, authors include antiprisms as snub polyhedra, as they are obtained by this construction from a degenerate "polyhedron" with only two faces (a dihedron).

Contents

Chiral snub polyhedra do not always have reflection symmetry and hence sometimes have two enantiomorphous (left- and right-handed) forms which are reflections of each other. Their symmetry groups are all point groups.

For example, the snub cube:

Snubhexahedronccw.gif Snubhexahedroncw.gif

Snub polyhedra have Wythoff symbol | p q r and by extension, vertex configuration 3.p.3.q.3.r. Retrosnub polyhedra (a subset of the snub polyhedron, containing the great icosahedron, small retrosnub icosicosidodecahedron, and great retrosnub icosidodecahedron) still have this form of Wythoff symbol, but their vertex configurations are instead

List of snub polyhedra

Uniform

There are 12 uniform snub polyhedra, not including the antiprisms, the icosahedron as a snub tetrahedron, the great icosahedron as a retrosnub tetrahedron and the great disnub dirhombidodecahedron, also known as Skilling's figure.

When the Schwarz triangle of the snub polyhedron is isosceles, the snub polyhedron is not chiral. This is the case for the antiprisms, the icosahedron, the great icosahedron, the small snub icosicosidodecahedron, and the small retrosnub icosicosidodecahedron.

In the pictures of the snub derivation (showing a distorted snub polyhedron, topologically identical to the uniform version, arrived at from geometrically alternating the parent uniform omnitruncated polyhedron) where green is not present, the faces derived from alternation are coloured red and yellow, while the snub triangles are blue. Where green is present (only for the snub icosidodecadodecahedron and great snub dodecicosidodecahedron), the faces derived from alternation are red, yellow, and blue, while the snub triangles are green.

Snub polyhedronImageOriginal omnitruncated polyhedronImageSnub derivationSymmetry groupWythoff symbol
Vertex description
Icosahedron (snub tetrahedron) Snub tetrahedron.png Truncated octahedron Omnitruncated tetrahedron.png Snub-polyhedron-icosahedron.png Ih (Th)| 3 3 2
3.3.3.3.3
Great icosahedron (retrosnub tetrahedron) Retrosnub tetrahedron.png Truncated octahedron Omnitruncated tetrahedron.png Snub-polyhedron-great-icosahedron.png Ih (Th)| 2 3/23/2
(3.3.3.3.3)/2
Snub cube
or snub cuboctahedron
Snub hexahedron.png Truncated cuboctahedron Great rhombicuboctahedron.png Snub-polyhedron-snub-cube.png O| 4 3 2
3.3.3.3.4
Snub dodecahedron
or snub icosidodecahedron
Snub dodecahedron ccw.png Truncated icosidodecahedron Great rhombicosidodecahedron.png Snub-polyhedron-snub-dodecahedron.png I| 5 3 2
3.3.3.3.5
Small snub icosicosidodecahedron Small snub icosicosidodecahedron.png Doubly covered truncated icosahedron Truncated icosahedron.png Snub-polyhedron-small-snub-icosicosidodecahedron.png Ih| 3 3 5/2
3.3.3.3.3.5/2
Snub dodecadodecahedron Snub dodecadodecahedron.png Small rhombidodecahedron with extra 12{10/2} faces Omnitruncated great dodecahedron with blue decagon and yellow square.svg Snub-polyhedron-snub-dodecadodecahedron.png I| 5 5/2 2
3.3.5/2.3.5
Snub icosidodecadodecahedron Snub icosidodecadodecahedron.png Icositruncated dodecadodecahedron Icositruncated dodecadodecahedron.png Snub-polyhedron-snub-icosidodecadodecahedron.png I| 5 3 5/3
3.5/3.3.3.3.5
Great snub icosidodecahedron Great snub icosidodecahedron.png Rhombicosahedron with extra 12{10/2} faces Omnitruncated great icosahedron with blue hexagon and yellow square.svg Snub-polyhedron-great-snub-icosidodecahedron.png I| 3 5/2 2
3.3.5/2.3.3
Inverted snub dodecadodecahedron Inverted snub dodecadodecahedron.png Truncated dodecadodecahedron Truncated dodecadodecahedron.png Snub-polyhedron-inverted-snub-dodecadodecahedron.png I| 5 2 5/3
3.5/3.3.3.3.5
Great snub dodecicosidodecahedron Great snub dodecicosidodecahedron.png Great dodecicosahedron with extra 12{10/2} faces Great dodecicosahedron.png no image yetI| 3 5/25/3
3.5/3.3.5/2.3.3
Great inverted snub icosidodecahedron Great inverted snub icosidodecahedron.png Great truncated icosidodecahedron Great truncated icosidodecahedron.png Snub-polyhedron-great-inverted-snub-icosidodecahedron.png I| 3 2 5/3
3.5/3.3.3.3
Small retrosnub icosicosidodecahedron Small retrosnub icosicosidodecahedron.png Doubly covered truncated icosahedron Truncated icosahedron.png no image yetIh|5/23/23/2
(3.3.3.3.3.5/2)/2
Great retrosnub icosidodecahedron Great retrosnub icosidodecahedron.png Great rhombidodecahedron with extra 20{6/2} faces Great rhombidodecahedron.png no image yetI| 2 5/33/2
(3.3.3.5/2.3)/2
Great dirhombicosidodecahedron Great dirhombicosidodecahedron.png Ih|3/25/3 3 5/2
(4.3/2.4.5/3.4.3.4.5/2)/2
Great disnub dirhombidodecahedron Great disnub dirhombidodecahedron.png Ih| (3/2) 5/3 (3) 5/2
(3/2.3/2.3/2.4.5/3.4.3.3.3.4.5/2.4)/2

Notes:

There is also the infinite set of antiprisms. They are formed from prisms, which are truncated hosohedra, degenerate regular polyhedra. Those up to hexagonal are listed below. In the pictures showing the snub derivation, the faces derived from alternation (of the prism bases) are coloured red, and the snub triangles are coloured yellow. The exception is the tetrahedron, for which all the faces are derived as red snub triangles, as alternating the square bases of the cube results in degenerate digons as faces.

Snub polyhedronImageOriginal omnitruncated polyhedronImageSnub derivationSymmetry groupWythoff symbol
Vertex description
Tetrahedron Linear antiprism.png Cube Uniform polyhedron 222-t012.png Snub-polyhedron-tetrahedron.png Td (D2d)| 2 2 2
3.3.3
Octahedron Trigonal antiprism.png Hexagonal prism Uniform polyhedron-23-t012.png Snub-polyhedron-octahedron.png Oh (D3d)| 3 2 2
3.3.3.3
Square antiprism Square antiprism.png Octagonal prism Octagonal prism.png Snub-polyhedron-square-antiprism.png D4d| 4 2 2
3.4.3.3
Pentagonal antiprism Pentagonal antiprism.png Decagonal prism Decagonal prism.png Snub-polyhedron-pentagonal-antiprism.png D5d| 5 2 2
3.5.3.3
Pentagrammic antiprism Pentagrammic antiprism.png Doubly covered pentagonal prism Pentagonal prism.png Snub-polyhedron-pentagrammic-antiprism.png D5h|5/2 2 2
3.5/2.3.3
Pentagrammic crossed-antiprism Pentagrammic crossed antiprism.png Decagrammic prism Prism 10-3.png Snub-polyhedron-pentagrammic-crossed-antiprism.png D5d| 2 2 5/3
3.5/3.3.3
Hexagonal antiprism Hexagonal antiprism.png Dodecagonal prism Dodecagonal prism.png Snub-polyhedron-hexagonal-antiprism.png D6d| 6 2 2
3.6.3.3

Notes:

Non-uniform

Two Johnson solids are snub polyhedra: the snub disphenoid and the snub square antiprism. Neither is chiral.

Snub polyhedronImageOriginal polyhedronImageSymmetry group
Snub disphenoid Snub disphenoid.png Disphenoid Disphenoid tetrahedron.png D2d
Snub square antiprism Snub square antiprism.png Square antiprism Square antiprism.png D4d

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Truncated icosidodecahedron Archimedean solid

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Uniform polyhedron Isogonal polyhedron with regular faces

In geometry, a uniform polyhedron has regular polygons as faces and is vertex-transitive. It follows that all vertices are congruent.

Pentagonal antiprism Antiprism with a 5-sided base

In geometry, the pentagonal antiprism is the third in an infinite set of antiprisms formed by an even-numbered sequence of triangle sides closed by two polygon caps. It consists of two pentagons joined to each other by a ring of 10 triangles for a total of 12 faces. Hence, it is a non-regular dodecahedron.

Great icosahedron Kepler-Poinsot polyhedron with 20 faces

In geometry, the great icosahedron is one of four Kepler-Poinsot polyhedra, with Schläfli symbol {3,52} and Coxeter-Dynkin diagram of . It is composed of 20 intersecting triangular faces, having five triangles meeting at each vertex in a pentagrammic sequence.

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Small snub icosicosidodecahedron Geometric figure

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Small retrosnub icosicosidodecahedron Uniform star polyhedron with 112 faces

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Uniform star polyhedron Self-intersecting uniform polyhedron

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Snub (geometry) Geometric operation applied to a polyhedron

In geometry, a snub is an operation applied to a polyhedron. The term originates from Kepler's names of two Archimedean solids, for the snub cube and snub dodecahedron. In general, snubs have chiral symmetry with two forms: with clockwise or counterclockwise orientation. By Kepler's names, a snub can be seen as an expansion of a regular polyhedron: moving the faces apart, twisting them about their centers, adding new polygons centered on the original vertices, and adding pairs of triangles fitting between the original edges.

Icosahedron Polyhedron with 20 faces

In geometry, an icosahedron is a polyhedron with 20 faces. The name comes from Ancient Greek εἴκοσι (eíkosi) 'twenty' and from Ancient Greek ἕδρα (hédra) ' seat'. The plural can be either "icosahedra" or "icosahedrons".

References

Polyhedron operators
Seed Truncation Rectification Bitruncation Dual Expansion Omnitruncation Alternations
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Uniform polyhedron-43-t0.svg Uniform polyhedron-43-t01.svg Uniform polyhedron-43-t1.svg Uniform polyhedron-43-t12.svg Uniform polyhedron-43-t2.svg Uniform polyhedron-43-t02.png Uniform polyhedron-43-t012.png Uniform polyhedron-33-t0.png Uniform polyhedron-43-h01.svg Uniform polyhedron-43-s012.png
t0{p,q}
{p,q}
t01{p,q}
t{p,q}
t1{p,q}
r{p,q}
t12{p,q}
2t{p,q}
t2{p,q}
2r{p,q}
t02{p,q}
rr{p,q}
t012{p,q}
tr{p,q}
ht0{p,q}
h{q,p}
ht12{p,q}
s{q,p}
ht012{p,q}
sr{p,q}