List of Johnson solids

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In geometry, polyhedra are three-dimensional objects where points are connected by lines to form polygons. The points, lines, and polygons of a polyhedron are referred to as its vertices, edges, and faces respectively. [1] A polyhedron is considered to be convex if: [2]

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A polyhedron is said to be regular if each of its faces are both equilateral and equiangular. [3] Regular polyhedra with the additional property of vertex-transitivity are called uniform polyhedra. [4] A Johnson solid (or Johnson–Zalgaller solid) is any convex polyhedron with only regular polygons as its faces. Some authors exclude uniform polyhedra—which include the Platonic solids and Archimedean solids, as well as prisms and antiprisms—from their definition. [5]

The Johnson solids are named for the mathematician Norman Johnson (1930–2017), who published a list of 92 convex polyhedra conforming with the above definition in 1966. Moreover, Johnson conjectured that the list was complete, and there could not be any other examples. Johnson's conjecture was later proven by the Russian-Israeli mathematician Victor Zalgaller (1920–2020) in 1969. [6] The first six Johnson solids are the square pyramid, pentagonal pyramid, triangular cupola, square cupola, pentagonal cupola, and pentagonal rotunda. These solids may be applied to construct another polyhedron that has the same properties, a process known as augmentation; attaching prism or antiprism to those is known as elongation or gyroelongation, respectively. Some others may be constructed by diminishment, the removal of those from the component of polyhedra, or by snubification, a construction by cutting loose the edges, lifting the faces and rotate in certain angle, after which adding the equilateral triangles between them. [7]

Every polyhedra has own characteristics, including symmetry and measurement. An object is said to be symmetrical if there is such transformation preserving the immunity to change. All of those transformations may be composed in a concept of group, alongside the number of elements, known as order. In two-dimensional space, these transformations include rotating around the center of a polygon and reflecting an object around the perpendicular bisector of a polygon. A polygon that is rotated symmetrically in is denoted by , a cyclic group of order ; combining with the reflection symmetry results in the symmetry of dihedral group of order . [8] In three-dimensional symmetry point groups, the transformation of polyhedra's symmetry includes the rotation around the line passing through the base center, known as axis of symmetry, and reflection relative to perpendicular planes passing through the bisector of a base; this is known as the pyramidal symmetry of order . Relatedly, polyhedra that preserve their symmetry by reflecting it across a horizontal plane are known as prismatic symmetry of order . The antiprismatic symmetry of order preserves the symmetry by rotating its half bottom and reflection across the horizontal plane. [9] The symmetry group of order preserves the symmetry by rotation around the axis of symmetry and reflection on horizontal plane; one case that preserves the symmetry by one full rotation and one reflection horizontal plane is of order 2, or simply denoted as . [10] The mensuration of polyhedra includes the surface area and volume. An area is a two-dimensional measurement calculated by the product of length and width, and the surface area is the overall area of all faces of polyhedra that is measured by summing all of them. [11] A volume is a measurement of the region in three-dimensional space. [12]

The following table contains the 92 Johnson solids of the edge length . Each of the columns includes the enumeration of Johnson solid, denoted as , [13] the number of vertices, edges, and faces, symmetry, surface area and volume .

Table of all 92 Johnson solids
Solid nameImageVerticesEdgesFaces Symmetry group and its order [14] Surface area and volume [15]
1 Equilateral
square
pyramid
Square pyramid.png 585 of order 8
2 Pentagonal
pyramid
Pentagonal pyramid.png 6106 of order 10
3 Triangular
cupola
Triangular cupola.png 9158 of order 6
4 Square
cupola
Square cupola.png 122010 of order 8
5 Pentagonal
cupola
Pentagonal cupola.png 152512 of order 10
6 Pentagonal
rotunda
Pentagonal rotunda.png 203517 of order 10
7 Elongated
triangular
pyramid
Elongated triangular pyramid.png 7127 of order 6
8 Elongated
square
pyramid
Elongated square pyramid.png 9169 of order 8
9 Elongated
pentagonal
pyramid
Elongated pentagonal pyramid.png 112011 of order 10
10 Gyroelongated
square
pyramid
Gyroelongated square pyramid.png 92013 of order 8
11 Gyroelongated
pentagonal
pyramid
Gyroelongated pentagonal pyramid.png 112516 of order 10
12 Triangular
bipyramid
Triangular dipyramid.png 596 of order 12
13 Pentagonal
bipyramid
Pentagonal dipyramid.png 71510 of order 20
14 Elongated
triangular
bipyramid
Elongated triangular dipyramid.png 8159 of order 12
15 Elongated
square
bipyramid
Elongated square dipyramid.png 102012 of order 16
16 Elongated
pentagonal
bipyramid
Elongated pentagonal dipyramid.png 122515 of order 20
17 Gyroelongated
square
bipyramid
Gyroelongated square dipyramid.png 102416 of order 16
18 Elongated
triangular
cupola
Elongated triangular cupola.png 152714 of order 6
19 Elongated
square
cupola
Elongated square cupola.png 203618 of order 8
20 Elongated
pentagonal
cupola
Elongated pentagonal cupola.svg 254522 of order 10
21 Elongated
pentagonal
rotunda
Elongated pentagonal rotunda.png 305527 of order 10
22 Gyroelongated
triangular
cupola
Gyroelongated triangular cupola.png 153320 of order 6
23 Gyroelongated
square
cupola
Gyroelongated square cupola.png 204426 of order 8
24 Gyroelongated
pentagonal
cupola
Gyroelongated pentagonal cupola.png 255532 of order 10
25 Gyroelongated
pentagonal
rotunda
Gyroelongated pentagonal rotunda.png 306537 of order 10
26 Gyrobifastigium Gyrobifastigium.png 8148 of order 8
27 Triangular
orthobicupola
Triangular orthobicupola.png 122414 of order 12
28 Square
orthobicupola
Square orthobicupola.png 163218 of order 16
29 Square
gyrobicupola
Square gyrobicupola.png 163218 of order 16
30 Pentagonal
orthobicupola
Pentagonal orthobicupola.png 204022 of order 20
31 Pentagonal
gyrobicupola
Pentagonal gyrobicupola.png 204022 of order 20
32 Pentagonal
orthocupolarotunda
Pentagonal orthocupolarotunda.png 255027 of order 10
33 Pentagonal
gyrocupolarotunda
Pentagonal gyrocupolarotunda.png 255027 of order 10
34 Pentagonal
orthobirotunda
Pentagonal orthobirotunda.png 306032 of order 20
35 Elongated
triangular
orthobicupola
Elongated triangular orthobicupola.png 183620 of order 12
36 Elongated
triangular
gyrobicupola
Elongated triangular gyrobicupola.png 183620 of order 12
37 Elongated
square
gyrobicupola
Elongated square gyrobicupola.png 244826 of order 16
38 Elongated
pentagonal
orthobicupola
Elongated pentagonal orthobicupola.png 306032 of order 20
39 Elongated
pentagonal
gyrobicupola
Elongated pentagonal gyrobicupola.png 306032 of order 20
40 Elongated
pentagonal
orthocupolarotunda
Elongated pentagonal orthocupolarotunda.png 357037 of order 10
41 Elongated
pentagonal
gyrocupolarotunda
Elongated pentagonal gyrocupolarotunda.png 357037 of order 10
42 Elongated
pentagonal
orthobirotunda
Elongated pentagonal orthobirotunda.png 408042 of order 20
43 Elongated
pentaognal
gyrobirotunda
Elongated pentagonal gyrobirotunda.png 408042 of order 20
44 Gyroelongated
triangular
bicupola
Gyroelongated triangular bicupola.png 184226 of order 6
45 Gyroelongated
square
bicupola
Gyroelongated square bicupola.png 245634 of order 8
46 Gyroelongated
pentagonal
bicupola
Gyroelongated pentagonal bicupola.png 307042 of order 10
47 Gyroelongated
pentagonal
cupolarotunda
Gyroelongated pentagonal cupolarotunda.png 358047 of order 5
48 Gyroelongated
pentagonal
birotunda
Gyroelongated pentagonal birotunda.png 409052 of order 10
49 Augmented
triangular
prism
Augmented triangular prism.png 7138 of order 4
50 Biaugmented
triangular
prism
Biaugmented triangular prism.png 81711 of order 4
51 Triaugmented
triangular
prism
Triaugmented triangular prism.png 92114 of order 12
52 Augmented
pentagonal
prism
Augmented pentagonal prism.png 111910 of order 4
53 Biaugmented
pentagonal
prism
Biaugmented pentagonal prism.png 122313 of order 4
54 Augmented
hexagonal
prism
Augmented hexagonal prism.png 132211 of order 4
55 Parabiaugmented
hexagonal
prism
Parabiaugmented hexagonal prism.png 142614 of order 8
56 Metabiaugmented
hexagonal
prism
Metabiaugmented hexagonal prism.png 142614 of order 4
57 Triaugmented
hexagonal
prism
Triaugmented hexagonal prism.png 153017 of order 12
58 Augmented
dodecahedron
Augmented dodecahedron.png 213516 of order 10
59 Parabiaugmented
dodecahedron
Parabiaugmented dodecahedron.png 224020 of order 20
60 Metabiaugmented
dodecahedron
Metabiaugmented dodecahedron.png 224020 of order 4
61 Triaugmented
dodecahedron
Triaugmented dodecahedron.png 234524 of order 6
62 Metabidiminished
icosahedron
Metabidiminished icosahedron.png 102012 of order 4
63 Tridiminished
icosahedron
Tridiminished icosahedron.png 9158 of order 6
64 Augmented
tridiminished
icosahedron
Augmented tridiminished icosahedron.png 101810 of order 6
65 Augmented
truncated
tetrahedron
Augmented truncated tetrahedron.png 152714 of order 6
66 Augmented
truncated
cube
Augmented truncated cube.png 284822 of order 8
67 Biaugmented
truncated
cube
Biaugmented truncated cube.png 326030 of order 16
68 Augmented
truncated
dodecahedron
Augmented truncated dodecahedron.png 6510542 of order 10
69 Parabiaugmented
truncated
dodecahedron
Parabiaugmented truncated dodecahedron.png 7012052 of order 20
70 Metabiaugmented
truncated
dodecahedron
Metabiaugmented truncated dodecahedron.png 7012052 of order 4
71 Triaugmented
truncated
dodecahedron
Triaugmented truncated dodecahedron.png 7513562 of order 6
72 Gyrate
rhombicosidodecahedron
Gyrate rhombicosidodecahedron.png 6012062 of order 10
73 Parabigyrate
rhombicosidodecahedron
Parabigyrate rhombicosidodecahedron.png 6012062 of order 20
74 Metabigyrate
rhombicosidodecahedron
Metabigyrate rhombicosidodecahedron.png 6012062 of order 4
75 Trigyrate
rhombicosidodecahedron
Trigyrate rhombicosidodecahedron.png 6012062 of order 6
76 Diminished
rhombicosidodecahedron
Diminished rhombicosidodecahedron.png 5510552 of order 10
77 Paragyrate
diminished
rhombicosidodecahedron
Paragyrate diminished rhombicosidodecahedron.png 5510552 of order 10
78 Metagyrate
diminished
rhombicosidodecahedron
Metagyrate diminished rhombicosidodecahedron.png 5510552 of order 2
79 Bigyrate
diminished
rhombicosidodecahedron
Bigyrate diminished rhombicosidodecahedron.png 5510552 of order 2
80 Parabidiminished
rhombicosidodecahedron
Parabidiminished rhombicosidodecahedron.png 509042 of order 20
81 Metabidiminished
rhombicosidodecahedron
Metabidiminished rhombicosidodecahedron.png 509042 of order 4
82 Gyrate
bidiminished
rhombicosidodecahedron
Gyrate bidiminished rhombicosidodecahedron.png 509042 of order 2
83 Tridiminished
rhombicosidodecahedron
Tridiminished rhombicosidodecahedron.png 457532 of order 6
84 Snub
disphenoid
Snub disphenoid.png 81812 of order 8
85 Snub
square
antiprism
Snub square antiprism.png 164026 of order 16
86 Sphenocorona Sphenocorona.png 102214 of order 4
87 Augmented
sphenocorona
Augmented sphenocorona.png 112617 of order 2
88 Sphenomegacorona Sphenomegacorona.png 122818 of order 4
89 Hebesphenomegacorona Hebesphenomegacorona.png 143321 of order 4
90 Disphenocingulum Disphenocingulum.png 163824 of order 8
91 Bilunabirotunda Bilunabirotunda.png 142614 of order 8
92 Triangular
hebespenorotunda
Triangular hebesphenorotunda.png 183620 of order 6
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Notes

  1. Meyer (2006), p.  418.
  2. Cromwell (1997), p.  77.
  3. Diudea (2018), p.  40.
  4. Flusser, Suk & Zitofa (2017), p.  126.
  5. Walsh (2014), p.  284.
  6. Parker (1997), p.  264.
  7. Uehara (2020), p.  62.
  8. Johnson (1966).
  9. Berman (1971).

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<span class="mw-page-title-main">Gyroelongated square bipyramid</span> 17th Johnson solid

In geometry, the gyroelongated square bipyramid is a polyhedron with 16 triangular faces. it can be constructed from a square antiprism by attaching two equilateral square pyramids to each of its square faces. The same shape is also called hexakaidecadeltahedron, heccaidecadeltahedron, or tetrakis square antiprism; these last names mean a polyhedron with 16 triangular faces. It is an example of deltahedron, and of a Johnson solid.

<span class="mw-page-title-main">Gyroelongated square pyramid</span> 10th Johnson solid (13 faces)

In geometry, the gyroelongated square pyramid is the Johnson solid that can be constructed by attaching an equilateral square pyramid to a square antiprism. It occurs in the chemistry such as square antiprismatic molecular geometry.

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In geometry, a square pyramid is a pyramid with a square base, having a total of five faces. If the apex of the pyramid is directly above the center of the square, it is a right square pyramid with four isosceles triangles; otherwise, it is an oblique square pyramid. When all of the pyramid's edges are equal in length, its triangles are all equilateral, and it is called an equilateral square pyramid.

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In geometry, the triangular cupola is the cupola with hexagon as its base and triangle as its top. If the edges are equal in length, the triangular cupola is the Johnson solid. It can be seen as half a cuboctahedron. Many polyhedrons can be constructed involving the attachment of the base of a triangular cupola.

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In geometry, the snub disphenoid, Siamese dodecahedron, triangular dodecahedron, trigonal dodecahedron, or dodecadeltahedron is a convex polyhedron with twelve equilateral triangles as its faces. It is not a regular polyhedron because some vertices have four faces and others have five. It is a dodecahedron, one of the eight convex deltahedra, and is the 84th Johnson solid. It can be thought of as a square antiprism where both squares are replaced with two equilateral triangles.

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In geometry, a polytope or a tiling is isotoxal or edge-transitive if its symmetries act transitively on its edges. Informally, this means that there is only one type of edge to the object: given two edges, there is a translation, rotation, and/or reflection that will move one edge to the other while leaving the region occupied by the object unchanged.

<span class="mw-page-title-main">Gyroelongated cupola</span>

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