Decahedral bipyramid
Ortogonal projection The 20 central dodecahedron vertices are shown in red, with 2 apex vertices in yellow.
Type	Polyhedral bipyramid
Schläfli symbol	{5,3} + { } dt{2,3,5}
Coxeter-Dynkin
Cells	24 {5}∨{ }
Faces	60 Isosceles triangles 12 pentagons
Edges	70 (30+20+20)
Vertices	22
Dual	Icosahedral prism
Symmetry group	[2,5,3], order 240
Properties	convex, isochoric

In 4-dimensional geometry, the dodecahedral bipyramid is the direct sum of a dodecahedron and a segment, {5,3} + { }. Each face of a central dodecahedron is attached with two pentagonal pyramids, creating 24 pentagonal pyramidal cells, 72 isosceles triangular faces, 70 edges, and 22 vertices. A dodecahedral bipyramid can be seen as two dodecahedral pyramids augmented together at their base.

It is the dual of a icosahedral prism.