Triangular bipyramid

Triangular bipyramid
Type	Bipyramid Deltahedra Johnson J11 – J12 – J13
Faces	6 triangles
Edges	9
Vertices	5
Vertex configuration	${\displaystyle 3\times 3^{2}+6\times 3^{2}}$
Symmetry group	${\displaystyle D_{3\mathrm {h} }}$
Dual polyhedron	triangular prism
Properties	convex
Net

In geometry, the triangular bipyramid is the hexahedron with six triangular faces, constructed by attaching two tetrahedra face-to-face. The same shape is also called the triangular dipyramid^[1][2] or trigonal bipyramid.^[3] If these tetrahedra are regular, all faces of triangular bipyramid are equilateral. It is an example of a deltahedron and of a Johnson solid.

Many polyhedra are related to the triangular bipyramid, such as new similar shapes derived in different approaches, and the triangular prism as its dual polyhedron. The many applications of triangular bipyramid include the trigonal bipyramid molecular geometry that describes its atom cluster, a solution of the Thomson problem, and the representation of color order systems by the eighteenth century.