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 convex polyhedron whose faces are regular polygons is known as a Johnson solid , or sometimes as a Johnson–Zalgaller solid. Some authors exclude uniform polyhedra from the definition. A uniform polyhedron is a polyhedron in which the faces are regular and they are isogonal; examples include Platonic and Archimedean solids as well as prisms and antiprisms. [3] The Johnson solids are named after American mathematician Norman Johnson (1930–2017), who published a list of 92 such polyhedra in 1966. His conjecture that the list was complete and no other examples existed was proven by Russian-Israeli mathematician Victor Zalgaller (1920–2020) in 1969. [4]

Some of the Johnson solids may be categorized as elementary polyhedra, meaning they cannot be separated by a plane to create two small convex polyhedra with regular faces. The Johnson solids satisfying this criteria are the first six—equilateral square pyramid, pentagonal pyramid, triangular cupola, square cupola, pentagonal cupola, and pentagonal rotunda. The criteria is also satisfied by eleven other Johnson solids, specifically the tridiminished icosahedron, parabidiminished rhombicosidodecahedron, tridiminished rhombicosidodecahedron, snub disphenoid, snub square antiprism, sphenocorona, sphenomegacorona, hebesphenomegacorona, disphenocingulum, bilunabirotunda, and triangular hebesphenorotunda. [5] The rest of the Johnson solids are not elementary, and they are constructed using the first six Johnson solids together with Platonic and Archimedean solids in various processes. Augmentation involves attaching the Johnson solids onto one or more faces of polyhedra, while elongation or gyroelongation involve joining them onto the bases of a prism or antiprism, respectively. Some others are constructed by diminishment, the removal of one of the first six solids from one or more of a polyhedron's faces. [6]

The following table contains the 92 Johnson solids, with edge length . The table includes the solid's enumeration (denoted as ). [7] It also includes the number of vertices, edges, and faces of each solid, as well as its symmetry group, surface area , and volume . Every polyhedron has its own characteristics, including symmetry and measurement. An object is said to have symmetry if there is a transformation that maps it to itself. All of those transformations may be composed in a group, alongside the group's number of elements, known as the 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 by is denoted by , a cyclic group of order ; combining this with the reflection symmetry results in the symmetry of dihedral group of order . [8] In three-dimensional symmetry point groups, the transformations preserving a polyhedron's symmetry include the rotation around the line passing through the base center, known as the axis of symmetry, and the reflection relative to perpendicular planes passing through the bisector of a base, which is known as the pyramidal symmetry of order . The transformation that preserves a polyhedron's symmetry by reflecting it across a horizontal plane is known as the 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 the horizontal plane; the specific case preserving the symmetry by one full rotation is of order 2, often 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; for a polyhedron, the surface area is the sum of the areas of all of its faces. [11] A volume is a measurement of a region in three-dimensional space. [12] The volume of a polyhedron may be ascertained in different ways: either through its base and height (like for pyramids and prisms), by slicing it off into pieces and summing their individual volumes, or by finding the root of a polynomial representing the polyhedron. [13]

The 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 pentagonal 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 hebesphenorotunda Triangular hebesphenorotunda.png 183620 of order 6

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<span class="mw-page-title-main">Cube</span> Solid object with six equal square faces

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<span class="mw-page-title-main">Regular icosahedron</span> Convex polyhedron with 20 triangular faces

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In geometry, a Johnson solid, sometimes also known as a Johnson–Zalgaller solid, is a strictly convex polyhedron whose faces are regular polygons. They are sometimes defined to exclude the uniform polyhedrons. There are ninety-two solids with such a property: the first solids are the pyramids, cupolas. and a rotunda; some of the solids may be constructed by attaching with those previous solids, whereas others may not. These solids are named after mathematicians Norman Johnson and Victor Zalgaller.

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<span class="mw-page-title-main">Truncated tetrahedron</span> Archimedean solid with 8 faces

In geometry, the truncated tetrahedron is an Archimedean solid. It has 4 regular hexagonal faces, 4 equilateral triangle faces, 12 vertices and 18 edges. It can be constructed by truncating all 4 vertices of a regular tetrahedron.

<span class="mw-page-title-main">Triangular bipyramid</span> Two tetrahedra joined by one face

A triangular bipyramid is a hexahedron with six triangular faces constructed by attaching two tetrahedra face-to-face. The same shape is also known as a triangular dipyramid or trigonal bipyramid. If these tetrahedra are regular, all faces of a triangular bipyramid are equilateral. It is an example of a deltahedron, composite polyhedron, and Johnson solid.

<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">Pentagonal bipyramid</span> Two pentagonal pyramids joined at the bases

The pentagonal bipyramid is a polyhedron with ten triangular faces. It is constructed by attaching two pentagonal pyramids to each of their bases. If the triangular faces are equilateral, the pentagonal bipyramid is an example of deltahedra, composite polyhedron, and 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 chemistry; for example, the square antiprismatic molecular geometry.

<span class="mw-page-title-main">Gyroelongated pentagonal pyramid</span> 11th Johnson solid (16 faces)

In geometry, the gyroelongated pentagonal pyramid is a polyhedron constructed by attaching a pentagonal antiprism to the base of a pentagonal pyramid. An alternative name is diminished icosahedron because it can be constructed by removing a pentagonal pyramid from a regular icosahedron.

<span class="mw-page-title-main">Square pyramid</span> Pyramid with a square base

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. It is called an equilateral square pyramid, an example of a Johnson solid.

<span class="mw-page-title-main">Pentagonal pyramid</span> Pyramid with a pentagon base

In geometry, pentagonal pyramid is a pyramid with a pentagon base and five triangular faces, having a total of six faces. It is categorized as a Johnson solid if all of the edges are equal in length, forming equilateral triangular faces and a regular pentagonal base. The pentagonal pyramid can be found in many polyhedrons, including their construction. It also occurs in stereochemistry in pentagonal pyramidal molecular geometry.

<span class="mw-page-title-main">Triangular cupola</span> Cupola with hexagonal base

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<span class="mw-page-title-main">Square cupola</span> Cupola with octagonal base

In geometry, the square cupola is the cupola with octagonal base. In the case of edges are equal in length, it is the Johnson solid, a convex polyhedron with faces are regular. It can be used to construct many polyhedrons, particularly in other Johnson solids.

<span class="mw-page-title-main">Elongated square gyrobicupola</span> 37th Johnson solid

In geometry, the elongated square gyrobicupola is a polyhedron constructed by two square cupolas attaching onto the bases of octagonal prism, with one of them rotated. It was once mistakenly considered a rhombicuboctahedron by many mathematicians. It is not considered to be an Archimedean solid because it lacks a set of global symmetries that map every vertex to every other vertex, unlike the 13 Archimedean solids. It is also a canonical polyhedron. For this reason, it is also known as pseudo-rhombicuboctahedron, Miller solid, or Miller–Askinuze solid.

<span class="mw-page-title-main">Snub disphenoid</span> Convex polyhedron with 12 triangular faces

In geometry, the snub disphenoid is a convex polyhedron with 12 equilateral triangles as its faces. It is an example of deltahedron and Johnson solid. It can be constructed in different approaches. This shape also has alternative names called Siamese dodecahedron, triangular dodecahedron, trigonal dodecahedron, or dodecadeltahedron.

<span class="mw-page-title-main">Triangular prism</span> Prism with a 3-sided base

In geometry, a triangular prism or trigonal prism is a prism with 2 triangular bases. If the edges pair with each triangle's vertex and if they are perpendicular to the base, it is a right triangular prism. A right triangular prism may be both semiregular and uniform.

In geometry, a pyramid is a polyhedron formed by connecting a polygonal base and a point, called the apex. Each base edge and apex form a triangle, called a lateral face. A pyramid is a conic solid with a polygonal base. Many types of pyramids can be found by determining the shape of bases, either by based on a regular polygon or by cutting off the apex. It can be generalized into higher dimensions, known as hyperpyramid. All pyramids are self-dual.

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