SmOs4Sb12 crystallizes in the cubic Im-3 space group. Sm(1) is bonded to twelve equivalent Sb(1) atoms to form SmSb12 cuboctahedra that share faces with eight equivalent Os(1)Sb6 octahedra. Os(1) is bonded to six equivalent Sb(1) atoms to form OsSb6 octahedra that share corners with six equivalent Os(1)Sb6 octahedra and faces with two equivalent Sm(1)Sb12 cuboctahedra. The corner-sharing octahedral tilt angles are 55°. Sb(1) is bonded in a 5-coordinate geometry to one Sm(1), two equivalent Os(1), and two equivalent Sb(1) atoms.
SmOs4Sb12 crystallizes in the cubic Im-3 space group. Sm(1) is bonded to twelve equivalent Sb(1) atoms to form SmSb12 cuboctahedra that share faces with eight equivalent Os(1)Sb6 octahedra. All Sm(1)-Sb(1) bond lengths are 3.49 Å. Os(1) is bonded to six equivalent Sb(1) atoms to form OsSb6 octahedra that share corners with six equivalent Os(1)Sb6 octahedra and faces with two equivalent Sm(1)Sb12 cuboctahedra. The corner-sharing octahedral tilt angles are 55°. All Os(1)-Sb(1) bond lengths are 2.63 Å. Sb(1) is bonded in a 5-coordinate geometry to one Sm(1), two equivalent Os(1), and two equivalent Sb(1) atoms. There is one shorter (2.93 Å) and one longer (3.01 Å) Sb(1)-Sb(1) bond length.