Hydrocarbons that have the same molecular geometry as the five Platonic solids, i.e. the tetrahedron, the cube, the octahedron, the dodecahedron and the icosahedron. These hydrocarbons have carbon atoms at the vertices of the polyhedra and single bonds along the edges. In fact, there are only two known Platonic hydrocarbons: cubane (C8H8) and dodecahedrane (C20H20). The hydrocarbon based on a tetrahedron (C4H4) does not exist because of angle strain, but substituted derivatives C4X4 are known. Angle strain is also the reason for the nonexistence of octahedrane (C6H6) and icosahedrane (C12H12).