Pentagonal retroprism

The pentagonal retroprism, also called the pentagonal crossed antiprism, is a prismatic isogonal polyhedron. It consists of 2 base pentagons and 10 isosceles triangles. Each vertex joins one pentagon and three triangles. It is a crossed antiprism based on a pentagon, seen as a 5/4-gon rather than 5/1. It cannot be made uniform.

It is isomorphic to the pentagonal antiprism.

In vertex figures
Pentagonal retroprisms appear as vertex figures of four uniform polychora: the small pentagonal retroprismatoverted dishecatonicosachoron, great pentagonal retroprismatoverted dishecatonicosachoron, pentagonal retroprismatoverted hexacosihecatonicosachoron, and quasiprismatohecatonicosachoron.