The runcinated 5-cell is constructed by expanding the cells of a 5-cell radially and filling in the gaps with triangular prisms (which are the face prisms and edge figures) and tetrahedra (cells of the dual pentachoron). It consists of 10 tetrahedra and 20 triangular prisms. The 10 tetrahedra correspond with the cells of a 5-cell and its dual.
Read more about Runcinated 5-cell: Runcitruncated 5-cell, Omnitruncated 5-cell, Related Polytopes