Sphenocorona | |
---|---|
![]() | |
Type |
Johnson J85 – J86 – J87 |
Faces | 12
triangles 2 squares |
Edges | 22 |
Vertices | 10 |
Vertex configuration | 4(33.4) 2(32.42) 2x2(35) |
Symmetry group | C2v |
Dual polyhedron | - |
Properties | convex |
Net | |
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In geometry, the sphenocorona is a Johnson solid with 12 equilateral triangles and 2 squares as its faces.
The sphenocorona was named by Johnson (1966) in which he used the prefix spheno- referring to a wedge-like complex formed by two adjacent lunes—a square with equilateral triangles attached on its opposite sides. The suffix -corona refers to a crownlike complex of 8 equilateral triangles. [1] By joining both complexes together, the resulting polyhedron has 12 equilateral triangles and 2 squares, making 14 faces. [2] A convex polyhedron in which all faces are regular polygons is called a Johnson solid. The sphenocorona is among them, enumerated as the 86th Johnson solid . [3] It is elementary, meaning it cannot be separated by a plane into two small regular-faced polyhedra. [4]
The surface area of a sphenocorona with edge length can be calculated as: [2] and its volume as: [2]
Let be the smallest positive root of the quartic polynomial . Then, Cartesian coordinates of a sphenocorona with edge length 2 are given by the union of the orbits of the points under the action of the group generated by reflections about the xz-plane and the yz-plane. [5]
The sphenocorona is also the vertex figure of the isogonal n-gonal double antiprismoid where n is an odd number greater than one, including the grand antiprism with pairs of trapezoid rather than square faces.
Sphenocorona | |
---|---|
![]() | |
Type |
Johnson J85 – J86 – J87 |
Faces | 12
triangles 2 squares |
Edges | 22 |
Vertices | 10 |
Vertex configuration | 4(33.4) 2(32.42) 2x2(35) |
Symmetry group | C2v |
Dual polyhedron | - |
Properties | convex |
Net | |
![]() |
In geometry, the sphenocorona is a Johnson solid with 12 equilateral triangles and 2 squares as its faces.
The sphenocorona was named by Johnson (1966) in which he used the prefix spheno- referring to a wedge-like complex formed by two adjacent lunes—a square with equilateral triangles attached on its opposite sides. The suffix -corona refers to a crownlike complex of 8 equilateral triangles. [1] By joining both complexes together, the resulting polyhedron has 12 equilateral triangles and 2 squares, making 14 faces. [2] A convex polyhedron in which all faces are regular polygons is called a Johnson solid. The sphenocorona is among them, enumerated as the 86th Johnson solid . [3] It is elementary, meaning it cannot be separated by a plane into two small regular-faced polyhedra. [4]
The surface area of a sphenocorona with edge length can be calculated as: [2] and its volume as: [2]
Let be the smallest positive root of the quartic polynomial . Then, Cartesian coordinates of a sphenocorona with edge length 2 are given by the union of the orbits of the points under the action of the group generated by reflections about the xz-plane and the yz-plane. [5]
The sphenocorona is also the vertex figure of the isogonal n-gonal double antiprismoid where n is an odd number greater than one, including the grand antiprism with pairs of trapezoid rather than square faces.