 Hexagonal bipyramid

Hexagonal bipyramid Type bipyramid Faces 12 triangles Edges 18 Vertices 8 Face configuration V4.4.6 Symmetry group D_{6h}, [6,2], (*226) Dual hexagonal prism Properties convex, facetransitive A hexagonal bipyramid is a polyhedron formed from two hexagonal pyramids joined at their bases. The resulting solid has 12 triangular faces, 8 vertices and 18 edges. The 12 faces are identical isosceles triangles.
It is one of an infinite set of bipyramids. Having twelve faces, it is a type of dodecahedron, although that name is usually associated with the regular polyhedral form with pentagonal faces. The term dodecadeltahedron is sometimes used to distinguish the bipyramid from the Platonic solid.
The hexagonal bipyramid has a plane of symmetry (which is horizontal in the figure to the right) where the bases of the two pyramids are joined. This plane is a regular hexagon. There are also six planes of symmetry crossing through the two apices. These planes are rhombic and lie at 30° angles to each other, perpendicular to the horizontal plane.
See also
 hexagonal trapezohedron A similar 12sided polyhedron with a twist and kite faces.
 Snub disphenoid Another 12sided polyhedron with 2fold symmetry and only triangular faces.
External links
 Weisstein, Eric W., "Dipyramid" from MathWorld.
 Olshevsky, George, Bipyramid at Glossary for Hyperspace.
 Virtual Reality Polyhedra The Encyclopedia of Polyhedra
 VRML model hexagonal dipyramid
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