SmPm3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Pm(2) and eight equivalent Pm(1) atoms to form SmPm12 cuboctahedra that share corners with four equivalent Sm(1)Pm12 cuboctahedra, corners with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pm12 cuboctahedra, edges with sixteen equivalent Pm(1)Pm8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pm12 cuboctahedra, faces with six equivalent Pm(2)Pm8Sm4 cuboctahedra, and faces with eight equivalent Pm(1)Pm8Sm4 cuboctahedra. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to four equivalent Sm(1), four equivalent Pm(1), and four equivalent Pm(2) atoms to form PmPm8Sm4 cuboctahedra that share corners with twelve equivalent Pm(1)Pm8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pm12 cuboctahedra, edges with eight equivalent Pm(1)Pm8Sm4 cuboctahedra, edges with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pm12 cuboctahedra, faces with four equivalent Pm(2)Pm8Sm4 cuboctahedra, and faces with ten equivalent Pm(1)Pm8Sm4 cuboctahedra. In the second Pm site, Pm(2) is bonded to four equivalent Sm(1) and eight equivalent Pm(1) atoms to form PmPm8Sm4 cuboctahedra that share corners with four equivalent Pm(2)Pm8Sm4 cuboctahedra, corners with eight equivalent Sm(1)Pm12 cuboctahedra, edges with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, edges with sixteen equivalent Pm(1)Pm8Sm4 cuboctahedra, faces with four equivalent Pm(2)Pm8Sm4 cuboctahedra, faces with six equivalent Sm(1)Pm12 cuboctahedra, and faces with eight equivalent Pm(1)Pm8Sm4 cuboctahedra.
SmPm3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Pm(2) and eight equivalent Pm(1) atoms to form SmPm12 cuboctahedra that share corners with four equivalent Sm(1)Pm12 cuboctahedra, corners with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pm12 cuboctahedra, edges with sixteen equivalent Pm(1)Pm8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pm12 cuboctahedra, faces with six equivalent Pm(2)Pm8Sm4 cuboctahedra, and faces with eight equivalent Pm(1)Pm8Sm4 cuboctahedra. All Sm(1)-Pm(2) bond lengths are 3.65 Å. All Sm(1)-Pm(1) bond lengths are 3.65 Å. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to four equivalent Sm(1), four equivalent Pm(1), and four equivalent Pm(2) atoms to form PmPm8Sm4 cuboctahedra that share corners with twelve equivalent Pm(1)Pm8Sm4 cuboctahedra, edges with eight equivalent Sm(1)Pm12 cuboctahedra, edges with eight equivalent Pm(1)Pm8Sm4 cuboctahedra, edges with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, faces with four equivalent Sm(1)Pm12 cuboctahedra, faces with four equivalent Pm(2)Pm8Sm4 cuboctahedra, and faces with ten equivalent Pm(1)Pm8Sm4 cuboctahedra. All Pm(1)-Pm(1) bond lengths are 3.65 Å. All Pm(1)-Pm(2) bond lengths are 3.65 Å. In the second Pm site, Pm(2) is bonded to four equivalent Sm(1) and eight equivalent Pm(1) atoms to form PmPm8Sm4 cuboctahedra that share corners with four equivalent Pm(2)Pm8Sm4 cuboctahedra, corners with eight equivalent Sm(1)Pm12 cuboctahedra, edges with eight equivalent Pm(2)Pm8Sm4 cuboctahedra, edges with sixteen equivalent Pm(1)Pm8Sm4 cuboctahedra, faces with four equivalent Pm(2)Pm8Sm4 cuboctahedra, faces with six equivalent Sm(1)Pm12 cuboctahedra, and faces with eight equivalent Pm(1)Pm8Sm4 cuboctahedra.