SmCe4 is alpha La-derived structured and crystallizes in the trigonal R-3m space group. Sm(1) is bonded to six equivalent Sm(1) and six equivalent Ce(1) atoms to form SmCe6Sm6 cuboctahedra that share corners with six equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with six Ce(2,2)Ce12 cuboctahedra; edges with six equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with six Ce(2,2)Ce12 cuboctahedra; edges with twelve equivalent Ce(1)Ce9Sm3 cuboctahedra; faces with six equivalent Sm(1)Ce6Sm6 cuboctahedra; and faces with twelve equivalent Ce(1)Ce9Sm3 cuboctahedra. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to three equivalent Sm(1), three equivalent Ce(2), and six equivalent Ce(1) atoms to form CeCe9Sm3 cuboctahedra that share corners with three equivalent Ce(2)Ce12 cuboctahedra, corners with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, edges with six equivalent Sm(1)Ce6Sm6 cuboctahedra, edges with nine equivalent Ce(2)Ce12 cuboctahedra, edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, faces with six equivalent Sm(1)Ce6Sm6 cuboctahedra, faces with six equivalent Ce(2)Ce12 cuboctahedra, and faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra. In the second Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine equivalent Ce(2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra, corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra, corners with six equivalent Ce(2)Ce12 cuboctahedra, edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra, edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, edges with twelve equivalent Ce(2)Ce12 cuboctahedra, faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra, and faces with twelve equivalent Ce(2)Ce12 cuboctahedra. In the third Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine Ce(2,2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra; corners with six equivalent Ce(2)Ce12 cuboctahedra; edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra; edges with twelve Ce(2,2)Ce12 cuboctahedra; faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra; and faces with twelve Ce(2,2)Ce12 cuboctahedra. In the fourth Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine Ce(2,2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra; corners with six equivalent Ce(2)Ce12 cuboctahedra; edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra; edges with twelve Ce(2,2)Ce12 cuboctahedra; faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra; and faces with twelve Ce(2,2)Ce12 cuboctahedra.
SmCe4 is alpha La-derived structured and crystallizes in the trigonal R-3m space group. Sm(1) is bonded to six equivalent Sm(1) and six equivalent Ce(1) atoms to form SmCe6Sm6 cuboctahedra that share corners with six equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with six Ce(2,2)Ce12 cuboctahedra; edges with six equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with six Ce(2,2)Ce12 cuboctahedra; edges with twelve equivalent Ce(1)Ce9Sm3 cuboctahedra; faces with six equivalent Sm(1)Ce6Sm6 cuboctahedra; and faces with twelve equivalent Ce(1)Ce9Sm3 cuboctahedra. All Sm(1)-Sm(1) bond lengths are 3.39 Å. All Sm(1)-Ce(1) bond lengths are 3.51 Å. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to three equivalent Sm(1), three equivalent Ce(2), and six equivalent Ce(1) atoms to form CeCe9Sm3 cuboctahedra that share corners with three equivalent Ce(2)Ce12 cuboctahedra, corners with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, edges with six equivalent Sm(1)Ce6Sm6 cuboctahedra, edges with nine equivalent Ce(2)Ce12 cuboctahedra, edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, faces with six equivalent Sm(1)Ce6Sm6 cuboctahedra, faces with six equivalent Ce(2)Ce12 cuboctahedra, and faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra. All Ce(1)-Ce(2) bond lengths are 3.32 Å. All Ce(1)-Ce(1) bond lengths are 3.39 Å. In the second Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine equivalent Ce(2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra, corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra, corners with six equivalent Ce(2)Ce12 cuboctahedra, edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra, edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra, edges with twelve equivalent Ce(2)Ce12 cuboctahedra, faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra, and faces with twelve equivalent Ce(2)Ce12 cuboctahedra. There are three shorter (3.35 Å) and six longer (3.39 Å) Ce(2)-Ce(2) bond lengths. In the third Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine Ce(2,2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra; corners with six equivalent Ce(2)Ce12 cuboctahedra; edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra; edges with twelve Ce(2,2)Ce12 cuboctahedra; faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra; and faces with twelve Ce(2,2)Ce12 cuboctahedra. All Ce(2)-Ce(1) bond lengths are 3.32 Å. There are three shorter (3.35 Å) and six longer (3.39 Å) Ce(2)-Ce(2,2) bond lengths. In the fourth Ce site, Ce(2) is bonded to three equivalent Ce(1) and nine Ce(2,2) atoms to form CeCe12 cuboctahedra that share corners with three equivalent Sm(1)Ce6Sm6 cuboctahedra; corners with three equivalent Ce(1)Ce9Sm3 cuboctahedra; corners with six equivalent Ce(2)Ce12 cuboctahedra; edges with three equivalent Sm(1)Ce6Sm6 cuboctahedra; edges with nine equivalent Ce(1)Ce9Sm3 cuboctahedra; edges with twelve Ce(2,2)Ce12 cuboctahedra; faces with six equivalent Ce(1)Ce9Sm3 cuboctahedra; and faces with twelve Ce(2,2)Ce12 cuboctahedra. All Ce(2)-Ce(1) bond lengths are 3.32 Å. There are three shorter (3.35 Å) and six longer (3.39 Å) Ce(2)-Ce(2,2) bond lengths.