SmY3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form SmY12 cuboctahedra that share corners with four equivalent Sm(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Sm4Y8 cuboctahedra, edges with eight equivalent Sm(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Sm4Y8 cuboctahedra, faces with four equivalent Sm(1)Y12 cuboctahedra, faces with six equivalent Y(2)Sm4Y8 cuboctahedra, and faces with eight equivalent Y(1)Sm4Y8 cuboctahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Sm(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YSm4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Sm4Y8 cuboctahedra, edges with eight equivalent Sm(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Sm4Y8 cuboctahedra, edges with eight equivalent Y(2)Sm4Y8 cuboctahedra, faces with four equivalent Sm(1)Y12 cuboctahedra, faces with four equivalent Y(2)Sm4Y8 cuboctahedra, and faces with ten equivalent Y(1)Sm4Y8 cuboctahedra. In the second Y site, Y(2) is bonded to four equivalent Sm(1) and eight equivalent Y(1) atoms to form YSm4Y8 cuboctahedra that share corners with four equivalent Y(2)Sm4Y8 cuboctahedra, corners with eight equivalent Sm(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Sm4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Sm4Y8 cuboctahedra, faces with four equivalent Y(2)Sm4Y8 cuboctahedra, faces with six equivalent Sm(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Sm4Y8 cuboctahedra.
SmY3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form SmY12 cuboctahedra that share corners with four equivalent Sm(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Sm4Y8 cuboctahedra, edges with eight equivalent Sm(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Sm4Y8 cuboctahedra, faces with four equivalent Sm(1)Y12 cuboctahedra, faces with six equivalent Y(2)Sm4Y8 cuboctahedra, and faces with eight equivalent Y(1)Sm4Y8 cuboctahedra. All Sm(1)-Y(2) bond lengths are 3.63 Å. All Sm(1)-Y(1) bond lengths are 3.61 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Sm(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YSm4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Sm4Y8 cuboctahedra, edges with eight equivalent Sm(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Sm4Y8 cuboctahedra, edges with eight equivalent Y(2)Sm4Y8 cuboctahedra, faces with four equivalent Sm(1)Y12 cuboctahedra, faces with four equivalent Y(2)Sm4Y8 cuboctahedra, and faces with ten equivalent Y(1)Sm4Y8 cuboctahedra. All Y(1)-Y(1) bond lengths are 3.63 Å. All Y(1)-Y(2) bond lengths are 3.61 Å. In the second Y site, Y(2) is bonded to four equivalent Sm(1) and eight equivalent Y(1) atoms to form YSm4Y8 cuboctahedra that share corners with four equivalent Y(2)Sm4Y8 cuboctahedra, corners with eight equivalent Sm(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Sm4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Sm4Y8 cuboctahedra, faces with four equivalent Y(2)Sm4Y8 cuboctahedra, faces with six equivalent Sm(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Sm4Y8 cuboctahedra.